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Association of apolipoprotein B and nuclear magnetic resonance spectroscopy--derived LDL particle number with outcomes in 25 clinical studies: assessment by the AACC lipoprotein and vascular diseases division working group on best practices.

LDL cholesterol (LDL-C), [7] a key cardiovascular biomarker, is recommended by National Cholesterol Education Program Adult Treatment Panel-III (NCEP-ATP III) guidelines (1) for assessing cardiovascular disease (CVD) risk and for monitoring lipid-lowering therapy. These guidelines are over 10 years old, and there are now numerous studies demonstrating that alternative measures of LDL are superior to LDL-C for CVD risk assessment (2). In addition, the heterogeneity of LDL particles and the difficulty in standardizing assays for LDL-C, an analyte that cannot be chemically well defined, has also made it difficult to develop accurate and robust assays. For example, direct assays for LDL-C from dyslipidemic samples have been shown to differ considerably from values obtained by reference method procedures (3, 4), thus potentially limiting the effectiveness of the assay in the very patients requiring accurate values. Recent recommendations from the National Lipid Association described several alternative biomarkers that may be useful for managing CVD patients, including LDL particle number (5). LDL particle number has been found to be a stronger predictor of CVD than LDL-C concentration (2).

The focus of this special report is the comparison between the 2 main diagnostic tests for LDL particle number, namely concentration of apolipoprotein B (apo B) and nuclear magnetic resonance (NMR)-derived LDL particle number (LDL-P), in their association with CVD and related conditions as outcome measures.

apo B is the main protein component of LDL and, because each LDL particle has 1 molecule of apo B, it is considered to be a direct measure of LDL particle number (2). The full-length form of apo B, called apo B-100, is found on VLDL, intermediate density lipoprotein (IDL), LDL, and lipoprotein(a) [Lp(a)], whereas a truncated form, called apo B-48, is found on chylomicrons and chylomicron remnants. Because of its relatively high abundance, apo B is readily measured in the clinical laboratory by several methods. The most common commercial assays are the immunoturbidimetric assay(ITA) and the immunonephelometric assay (INA). Typically, these methods measure both apo B-100 and apo B-48, but in fasting samples greater than 95% of apo Bin plasma is apo B-100 and almost all of it is associated with LDL (6). Therefore, the measurement of plasma apo B concentration is essentially an estimate of LDL-apo B concentration or LDL particle number (7). Calibration of these assays is attained through the use of calibrators provided by the assay kit manufacturer, which may now have set points established by the CDC Lipid Standardization Program (LSP) using the WHO-IFCC reference material SP3-08 as secondary reference material and the designated comparison method (DCM). In many studies, apo B has been shown to be superior or at least equivalent to LDL-C for assessing patients for CVD risk (2).

LDL particle number can also be estimated by NMR of plasma (8), a proprietary method that has been available since 1997 as part of the NMR LipoProfile[R] from LipoScience, a specialty lipid reference laboratory. The terminal methyl groups on lipoprotein associated lipids emit a characteristic NMR spectrum, which varies depending on the size of the lipoprotein particle, allowing NMR to estimate the different size LDL and other lipoprotein subfractions (9). A specific spectral region captures the NMR signal emitted by the total number of terminal methyl group protons of phospholipids, cholesterol, cholesteryl esters, and triglycerides of the different lipoprotein particle subclasses (10). A least squares deconvolution process is used to calculate the individual subclass signal amplitudes. The deconvolution algorithm was developed using a library of different lipoprotein size subclasses, obtained from a diverse donor population, containing isolated VLDL, LDL, and HDL. Total LDL-P is determined by summing the concentrations of the individual LDL subfractions, including IDL and Lp(a). Numerous studies have shown the superiority of LDL-P over LDL-C for both identifying patients at CVD risk and in monitoring patients on lipid-lowering therapy (2).

Ion mobility analysis has been proposed as another method to measure LDL particle number directly (11), although the accuracy of the method has been disputed (12). This assay currently is available only at Quest Diagnostics Nichols Institute. Ion mobility analysis has been reported for only one clinical study (13) and has not been compared to other LDL-P assays.

Non-HDL-C has also been shown in several studies to be a predictor of CVD events (5, 14) and serves as a secondary treatment goal by the NCEP for those patients with hypertriglyceridemia who have met LDL-C treatment goals. Non-HDL-C is readily calculated from standard lipid panels as the difference between total cholesterol and HDL-C and, similar to apo B, encompasses all putative atherogenic lipoproteins. Although non-HDL-C reflects total atherogenic particle number better than LDL-C, unlike apo B, non-HDL-C does not accurately reflect atherogenic particle number and may leave residual CVD risk after treatment goals are met, due to the variability of the composition of the constituent lipoproteins.

In this study, we reviewed the literature on apo B and LDL-P and examined 25 clinical studies that included both parameters to compare their utility as biomarkers for CVD risk, as well as other related conditions and parameters, such as carotid intima media thickening (CIMT), diabetes and metabolic syndrome (MetSyn).

Methods

A PubMed survey of the medical literature, using the key terms apo B, LDL-P, and the name Otvos, was performed to find clinical trials of the association of both apo B and LDL-P with specific outcomes, such as CVD, the presence of carotid atherosclerosis, or metabolic diseases or conditions, including diabetes mellitus and MetSyn. A total of 26 publications was found through June 2012. One publication with an outcome of newborn body weight (15) was excluded from our analysis. The relevant data for each clinical study is summarized in Table 1. Each study was identified with an order number, study acronym, and year of publication, e.g., 1 Veterans Affairs High-Density Lipoprotein Intervention Trial (VA-HIT) 2006. An assessment was made for each clinical study or relevant portion thereof whether apo B or LDL-P was statistically related to the outcome (Table 2). The study or subpart was then assigned to 1 of 4 outcome categories: 1. apo B statistically significant, LDL-P not significant; 2. LDL-P statistically significant, apo B not significant; 3. both statistically significant; or 4. neither statistically significant.

Results

REVIEW OF SURVEYED PUBLICATIONS

Comprehensive summaries of the 25 surveyed clinical studies are presented in the Data Supplement that accompanies the online version of this report at http:// www.clinchem.org/content/vol59/issue5. The associations of apo B and LDL-P to clinical outcomes are shown in Table 1. Depending on the study design and statistical analyses, associations are indicated by odds ratio (OR), hazard ratio (HR), relative risk (RR), regression analysis, or comparison of means. ORs, HRs, and RRs are also illustrated as a forest plot in Figure 1, providing the risk estimate [+ or -] 95% CI for a 1 mean (SD) increment in the biomarker concentration. Intervals which fall below 1.0 are considered statistically not significant. The comparisons of apo B and LDL-P are shown in Table 2, based on the 4 outcome categories described in Methods, using data shown in Table 1 and Figure 1. A brief summary of findings for various outcomes follows.

[FIGURE 1 OMITTED]

Prediction of CVD or events. In 15 of 19 comparisons, apo B and LDL-P both were associated (n = 12) or neither was associated (n = 3) with study outcomes, giving a high concordance between the 2 biomarkers (78.9%), particularly with regard to prediction of future CVD events (16-22). On the basis of risk ratios, LDL-P was more strongly associated with events in the 1 VA-HIT 2006 and 2 Women's Health Study (WHS) 2002 studies, whereas apo B was a stronger predictor in the 3 WHS 2009, 4 Framingham Offspring Study (FOS) 2007, and 5 FOS 2007a studies. In 4 Heart Protection Study (HPS) 2012, both biomarkers were essentially identically associated with the occurrence of major occlusive coronary events (MOCEs) and the need for revascularization.

Because of the lack of data for non-HDL-C, a meaningful 4-way comparison with apo B and LDL-P was possible for only the 6 studies in this prediction category (see online Supplemental Table 1). In this limited data set, apo B, LDL-P, and non-HDL-C were comparable in the number of comparisons which were significant (13 to 15 of 19 total comparisons), whereas LDL-C was significant in only 9 comparisons.

Presence of carotid atherosclerosis. Both apo B and LDL-P were strongly predictive of carotid atherosclerosis (23-27). For most outcomes LDL-P was a stronger predictor than apo B. Both apo B and LDL-P agreed in 17 of 24 outcomes, for a concurrence rate of 70.8%.

Prediction of MetSyn. In 8 of 9 clinical outcomes (88%), apo B and LDL-C were equivalently associated with the presence of MetSyn or with the effect of statin therapy on patients with MetSyn (28-30).

Association with diabetes mellitus or diabetic complications. In general, both apo B and LDL-P were equally associated with diabetic nephropathy and distribution by sex and glycemic control in individuals with type 1 diabetes (31-34). In addition, the strengths of the associations were similar. Similar reductions of both apo B and LDL-P were observed as a result of treatment of individuals with type 2 diabetes with colesevelam. Overall, 14 of 16 outcomes were in agreement between apo B and LDL-P (87.5%).

Association with plasma lipids and lipoproteins. A consistent role of apo B or LDL-P in this grouping is not evident because of the number of outcomes in which both parameters were not statistically significant; however, in instances in which both were significant, both were generally affected to the same extent (35-39).

Prediction of miscellaneous associations. In the 1 small study reported for venous thromboembolic disease (VTE) [24 Venous Thromboembolic Disease Study (VTES) 2005], LDL-P was superior to apo B in predicting VTE in men; LDL-P alone was statistically significant for all outcomes (n = 4) (40-41). Both apo B and LDL-P predicted incident hypertension (HTN) in initially healthy women, but the ORs were larger for LDL-P than for apo B.

ASSESSMENT OF OVERALL CONCORDANCE BETWEEN apo B AND LDL-P ACROSS STUDIES

The comparisons were grouped into 1 of 4 distinct outcome categories as described in Methods. For the 25 studies reported here, both apo B and LDL-P were significant for at least 1 outcome in 21 (84.0%) of the 25 studies. Neither was significant for any outcomes in only 1 study. In 2 studies, LDL-P was significant for at least 1 outcome whereas apo B was not, and in 1 study apo B was significant for at least 1 outcome whereas LDL-P was not. In the 25 studies, there were a total of 85 outcome measures compared. Table 2 shows that, of a total of 85 observed comparisons of various types, 50 fell into the "both statistically significant" category (58.8%), 13 fell into the "LDL-P statistically significant, apo B not significant" category (15.3%), and 5 fell into the "apo B statistically significant, LDL-P not significant" category (5.9%). These data indicate that both apo B and LDL-P were generally in agreement in their association with diverse clinical outcomes (58.8%), but with a substantial amount of discordance (21.2%) in which one biomarker was statistically significant whereas the other was not. The "neither statistically significant" category (20.0%) is considered noninformative because it does not allow a comparison of one biomarker to the other. Although several comparisons showed equivalent strength of association with the outcome measures for apo B and LDL-P, in some cases one or the other biomarker appeared to be more strongly associated with the outcome variable. In these cases, LDL-P showed a significant association with a clinical outcome more often than apo B alone, and the level of statistical significance, as indicated by the P value, and the strength of association, as indicated by the OR, RR, and HR, was more often higher for LDL-P than it was for apo B (Table 1, Figure 1).

Discussion

At present, LDL-C is used as the primary lipoprotein indicator of cardiovascular risk in the US and serves as the primary treatment goal in the NCEP-ATP III guidelines. As new clinical studies emerge, the relative utility of biomarkers for assessment of CVD should be reevaluated and treatment guidelines revised accordingly. This occurred in Canada, where apo B measurements were incorporated into the clinical guidelines for the assessment of CVD in 2003 (42). Similar recommendations have recently been made in the US (5).

As reviewed recently, LDL particle number, as either apo B or LDL-P, has been shown to be a better predictor of future CVD events than LDL-C and a better monitor of therapy in many (2), but not all, studies (18,21,43). Although the clinical utility of the measurement of LDL particle number is currently debated, the recent report from an expert panel of lipid specialists presents a reasonable use of these biomarkers for diagnostic and monitoring purposes in selected groups of patients (5). Given that both apo B and LDL-P measure the same atherogenic indicators, primarily LDL particle number, their association with various disease states or conditions would be expected to be strongly related. To determine their relative utility, we chose to review all publications that allow direct comparison of the association of apo B and LDL-P to clinical outcomes. Our review of 25 relevant publications shows that neither was consistently superior to the other (Table 2). Less clear is the lack of equivalency that is observed in some studies, which, as discussed below, may be due to differences in the analytical methods used to measure these biomarkers.

As observed in our limited comparison of 4 biomarkers (see online Supplemental Table 1), both non-HDL-C and apo B are superior to LDL-C in predicting CVD risk. Conventional wisdom is that non-HDL-C is better than LDL-C because it includes the cholesterol in VLDL. However, it has been clearly shown that the amount of cholesterol in VLDL particles cannot explain the increased RR seen with non-HDL-C versus LDL-C (44). The better explanation is that non-HDL-C more accurately reflects the number of LDL particles (44). In a metaanalysis of LDL-C, non-HDL-C, and apo B as risk factors for CVD, Sniderman et al. demonstrated the superiority of apo B over non-HDL-C and LDL-C, with RRs in the order apo B > non-HDL-C > LDL-C (45). These data suggest that treating to goal with non-HDL-C leaves residual risk.

COMPARISON OF apo B ITA/INA AND LDL-P METHODS

The reliable application of risk cutpoints and treatment goals, which are based on data derived from epidemiologic trials, requires precise and accurate analytical measurements to be medically useful (Table 3). Relatively small errors in measurement can lead to the misclassification of individuals with regard to risk, with potentially serious consequences (4). The accuracy of a method is established by standardization, a process involving a reference system of primary and secondary reference measurement procedures and reference materials, which assures that reported results for an analyte will agree with other laboratories over time, independent of methodology (46). Bias, the measure of inaccuracy, is the difference of a measured value from the true value of an analyte. Bias among laboratories in the measurement of apo B would be minimized if they all used standardized methods, but for most of the studies reported here, it is not possible to determine whether standardized assays were used or used in the format under which they were standardized (see online Supplemental Table 2). None of the 25 publications reviewed provided a measure of bias to a reference method. Precision is a measure of the reproducibility of measurement and is expressed as % CV. An imprecise method, even though on average free of bias, will still result in excessive error on individual measurements. Together, accuracy and precision define the total error associated with a measurement process. Performance goals for accuracy and precision for an analyte are set so that the requisite medical usefulness of a biomarker is attained. At this time, no performance goals have been established by the NCEP or any other expert panel for either apo B or LDL-P (46, 47). However, a 6.0% maximum bias, based on biological variation and analytical imprecision, has been suggested for apo B, which is similar to the one for LDL-C (6.8%) (48). No such information is available for LDL-P. A standardization program for apo B is provided by the Northwest Lipid Metabolism and Diabetes Research Laboratories (NWLMDRL) in Seattle, WA, which determines precision and bias relative to an in-house method, accepted as a DCM for apo B by the CDC LSP (47). Thus, apo B is standardized using the same CDC LSP which is used for the standardization of cholesterol, LDL-C, and HDL-C. The strategy of the LSP is to work directly with manufacturers to standardize their commercial assays, which are then used by clinical laboratories. Although there is no formal standardization program for LDL-P, it could conceivably conform to the apo B LSP, by adding the VLDL particle number to the LDL-P and converting nanomoles per liter (nmol/L) to mass units (mg/dL) based on the molecular weight of apo B (550 000 Da) (49). This conversion recognizes that both total plasma apo B and LDL-P measurements presumably include IDL and Lp(a), in addition to LDL.

The methods for only 4 studies listed in online Supplemental Table 2 were stated to be standardized for apo B, and that was by verification of calibration to the apo B assay kit manufacturer, Incstar, which had taken part in the WHO-IFCC standardization program using SP3-07 as reference material (50, 51). Presumably, a single laboratory performed the apo B measurements for these studies. Three other laboratories were described as standardized through the LSP for lipids, but it is not clear that they were also standardized for apo B (see online Supplemental Table 2). Standardization was not claimed for any of the remaining 17 methods. As noted by several authors, a major concern about the use of apo B for assessment and treatment of CVD is the lack of rigorous standardization among methods and laboratories (49, 52). Interestingly, this concern has not been shared for LDL-P, which is not standardized to any reference system, because it is measured in only one laboratory, thereby eliminating the problems of among-method and among-laboratory variability. In fact, standardization is not a prerequisite for the establishment of an association of a biomarker with a clinical outcome within any single laboratory and study, but it is critical for comparison between laboratories and studies or if data from several laboratories will be pooled for the establishment of disease risk assessments or treatment cutpoints.

A major advantage of the NMR method vs apo B is the determination not only of LDL-P but also LDL subclasses and other major lipoprotein classes; thus NMR provides considerably more information with the analysis than does the measurement of apo B. Although additional information may contribute to the value of an assay, only that information which has been shown to provide proven clinical significance should be reported to the patient. Also, the NMR measurement of LDL-P appears to be generally more precise than that of apo B. For the few laboratories that reported % CV for the measurement of apo B, it is assumed to be a measure of between-run precision, with CVs ranging from 5% to 11%, whereas the same measure for LDL-P was from 2% to 4% (8). This disparity in precision may give LDL-P an advantage over apo B in discerning small differences between groups in a clinical study. According to the College of American Pathologist's proficiency testing reports [2011 Accuracy-Based Lipid Surveys, ABL-A and ABL-B (http://www.cap.org/apps/cap.portal)] for apo B, the within-method, between-laboratory precision averaged about 5.96% for all the methods tested and the overall precision (between method/between laboratory) precision averaged about 6.75% for all methods in their program. In contrast, LDL-P has no between-laboratory precision value because it is measured in only one laboratory. In addition, the measurement of LDL-P in a single laboratory would also be expected to benefit from the long-term stability of measurement, although the deconvolution algorithm used by LipoScience has evolved over time (53). In contrast, the stability of apo B measurements requires the assay kit providers to reassess the calibrator accuracy with each change in the lots of antisera and calibrators. The lack of between-laboratory variability and extended long-term stability would allow pooling of LDL-P data collected in different clinical studies over long periods of time with less variability than for apo B data, which may be impacted by the assay antibody and method as well as laboratory and assay bias issues.

Several other factors may also impact the use of apo B and LDL-P measurements (Table 3).

Samples. For both methods, serum or plasma from either fed or fasted individuals may be used. Samples have been reported to be stable for at least 10 years for NMR analysis when frozen at -70[degrees]C, allowing the analysis of reserved study samples (8), whereas apo B changes that occur upon freezing and storage appear to be method dependent (54). The NMR-based LDL-P assay uses 200 [micro]L of sample and the immunoassay of apo B generally requires only about 2 to 15 [micro]L of sample (depending on the vendor).

Test availability. Increasing recognition of the superiority of measures of particle number over LDL-C will likely drive increased demand for apo B and LDL-P measurements. The number of lipid panels performed annually in the US to obtain LDL-C is estimated to be 216 000 000 (55). Considering the implications of a shift to particle measurement, it must be recognized that the apo B measurement is inherently scalable, with many vendors providing assays that can be performed on almost every chemistry analyzer in any clinical laboratory and physician office (Table 3). Although the LDL-P test is performed only by the LipoScience reference laboratory, LipoScience has recently received US Food and Drug Administration clearance for distribution of its NMR analyzers for lipoprotein testing to other clinical laboratories. Nevertheless, the capital expense and logistical complications initially may still limit availability of the LDL-P assay.

Expense. Based on the Medicare fee schedule, the incremental cost of adding an apo B or LDL-P test to a lipid panel is about $17 or $30-$40, respectively, depending on the payer. There is some concern as to the cost benefit of the added testing given the additional expense (52). However, according to at least one US Expert Panel the incremental expense is warranted in certain patients (5). The therapeutic value relative to the incremental cost of each of the measurements is currently under aggressive debate (5, 56).

SUGGESTED EXPERIMENT TO FURTHER COMPARE

apo B TO LDL-P

A limitation of our study is that none of the studies reviewed were specifically designed to compare results and clinical utility of apo B vs LDL-P. Further work is recommended to compare these methods on a variety of sample types and determine their utility as predictive biomarkers in various diseases and conditions. An example of an appropriate study was recently described by Miller, et al. (3). Briefly, samples were collected from healthy individuals and from individuals with a variety of dyslipidemic and cardiovascular diseases. The samples were analyzed with a panel of HDL-C and LDL-C clinical assays, as well as by the appropriate reference measurement procedures. Trueness and total error relative to the RMP were determined. A similar experiment should be conducted using a variety of standardized apo B assays and the LipoScience LDL-P assay and comparing with the CDC LSP DCM for apo B. To make a suitable comparison to plasma apo B, NMR VLDL-P values would need to be added to the LDL-P (nmol/L), which would then be converted to apo B equivalents (mg/dL) by multiplication by the factor 0.055 (49). As has been previously described when comparing the clinical utility of LDL-P vs LDL-C as a biomarker (57), the discordant cases between apo B vs LDL-P will likely be most revealing in terms of the relative merits of the 2 tests.

When compared for all the clinical outcomes in the 25 publications reviewed here, associations of apo B and LDL-P were generally equivalent, although when discordance between associations with outcome measures occurred, LDL-P appeared more often to be superior to apo B, based on statistical strength. The finding that the 2 biomarkers show similar CVD risk prediction is expected given that both methods measure, in addition to LDL-P, the particle numbers of IDL and Lp(a). Total plasma apo B may additionally include VLDL and chylomicron remnants, which are typically present in small quantities in fasting samples. Although a standardization program for apo B exists, it appears from an inspection of the published studies to be underutilized, particularly for measurements made in older clinical studies, thereby confounding the use of pooled data from multiple trials to set disease assessment and treatment cut-points.

RECOMMENDATIONS

Based on the preceding observations, we make the following recommendations:

1. The measurement of particle number, either as concentration of apo B or LDL-P should be incorporated into the guidelines for the assessment of CVD risk.

2. Manufacturers of analytical systems for measurement of apo B concentration or particle number should produce well-characterized, robust assays with disclosure of analytical properties, such as antibody specificity, and information regarding standardization.

3. All manufacturers should standardize their assays according to WHO-IFCC reference materials by the currently available standardization program at the NWLMDRL using the apo B DCM.

4. Researchers and laboratories using these assays in clinical studies should calibrate or verify the accuracy through the use of frozen serum samples from NWLMDRL.

5. Performance goals (precision, bias, total error) for LDL-P assays should be determined by expert consensus, as was done for other lipid/lipoprotein biomarkers.

6. Additional studies should be performed to determine the optimum specificities for apo B antibodies (e.g. apo B-100, apo B-48, apo [a]), and to the various apo B-carrying particles, to best characterize CVD risk and monitor therapy.

7. Further studies should be performed to compare apo B to LDL-P using a variety of representative specimens to better understand the inherent differences and contributors to discordance, as well as relative advantages and disadvantages of the 2 assays.

Conclusions

In the majority of studies, both apo B and LDL-P were comparable in association with clinical outcomes. Where discordant, the differences maybe due to inherent methodological differences between the 2 technologies as well as the large number of methodologies employed to measure apo B and the consistency of the NMR method, which was performed using a single method in a single laboratory for all the studies. The 2 markers appear to be nearly equivalent in their ability to assess risk for CVD, and as previously published by the Lipoprotein and Vascular Diseases Division Working Group on Best Practices, both measures have consistently been shown to be stronger risk factors than LDL-C (2). We continue to support the adoption of apo B and/or LDL-P as indicators of atherogenic particle numbers into cardiovascular risk screening and treatment guidelines. Currently, in the opinion of this Working Group on Best Practices, apo B appears to be the preferred biomarker for guideline adoption because of its widespread availability, scalability, standardization, and relatively low cost. As LDL-P is expected to become more readily available in the near future, with a possible lowering of cost and potentially superior performance in direct comparison with apo B, it may become the preferred test as a cardiovascular biomarker. Although this study primarily was aimed at comparing apo B and LDL-P, results of our limited evaluation of non-HDL-C and current literature (44, 45) suggest that the high performance of non-HDL-C likely is related to being an indirect way of estimating apo B.

Author Contributions: All authors confirmed they have contributed to the intellectual content of this paper and have met the following 3 requirements: (a) significant contributions to the conception and design, acquisition of data, or analysis and interpretation of data; (b) drafting or revising the article for intellectual content; and (c) final approval of the published article.

Authors' Disclosures or Potential Conflicts of Interest: Upon manuscript submission, all authors completed the author disclosure form. Disclosures and/or potential conflicts of interest:

Employment or Leadership: J.P. McConnell, HDL; T. Mallory, HDL.

Consultant or Advisory Role: T.G. Cole, HDL.

Stock Ownership: J.P. McConnell, HDL; T. Mallory, HDL.

Honoraria: None declared.

Research Funding: None declared.

Expert Testimony: None declared.

Patents: None declared.

Role of Sponsor: None declared.

Acknowledgments: The authors thank Maureen Sampson for her technical expertise in graphical design.

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(29.) Rosenson, RD, Otvos JD, Hsia J. Effects of rosuvastatin and atorvastatin on LDL and HDL particle concentrations in patients with metabolic syndrome. Diabetes Care 2009;32:1087-91.

(30.) Clarenbach JJ, Grundy S, Palacio N, Vega GL. Relationship of apolipoprotein B levels to the number of risk factors for metabolic syndrome. J Investig Med 2007;55:237-47.

(31.) Jenkins AJ, Lyons TJ, Zheng D, Otvos JD, Lackland DT, McGee D, et al. Lipoproteins in the DCCT/EDIC cohort: associations with diabetic nephropathy. Kidney Int 2003;64:817-28.

(32.) Jenkins AJ, McGee D, Lyons TJ, Garvey WT, Zheng D, Klein RL, et al. Serum lipoproteins in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Intervention and Complications Cohort: associations with gender and glycemia. Diabetes Care 2003;26:810-8.

(33.) Rosensen RS, Abby SL, Jones MR. Colesevelam HCl effects on atherogenic lipoprotein subclasses in subjects with type 2 diabetes. Atherosclerosis 2009;204:342-4.

(34.) Zieve FJ, Kalin MF, Schwartz SL, Jones MR, Baily WL. Results of the Glucose-Lowering Effect of WelChol Study (GLOWS): a randomized, double blind, placebo-controlled pilot study evaluating the effect of colesevelam hydrochloride on glycemic control in subjects with type 2 diabetes. Clin Ther 2007;29:74-83.

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(36.) Giri S, Thompson PD, Taxel P, Contois JH, Otvos J, Allen R, et al. Oral estrogen improves serum lipids, homocysteine and fibrinolysis in elderly men. Atherosclerosis 1998;137:359-66.

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Thomas G. Cole, [1] * John H. Contois, [2] Gyorgy Csako, [3] Joseph P. McConnell, [4] Alan T. Remaley, [3] Sridevi Devaraj, [5] Daniel M. Hoefner, [4] Tonya Mallory, [4] Amar A. Sethi, [6] and G. Russell Warnick [4]

[1] Thom Cole Consulting, LLC, St. Louis, MO; [2] Sun Diagnostics, LLC, New Gloucester, ME; [3] Department of Laboratory Medicine, NIH, Bethesda, MD; [4] Health Diagnostic Laboratory, Inc., Richmond, VA; [5] Department of Clinical Chemistry, Texas Children's Hospital, Houston, TX; [6] Pacific Biomarkers, Inc., Seattle, WA.

* Address correspondence to this author at: Thom Cole Consulting, LLC, 594 Gederson Lane, St. Louis, MO, 63122. Fax 314-821-6940; e-mail tgchol@aol.com.

Received October 11, 2012; accepted January 10, 2013.

Previously published online at DOI: 10.1373/clinchem.2012.196733

[7] Nonstandard abbreviations: LDL-C, LDL cholesterol; NCEP-ATP III, National Cholesterol Education Program Adult Treatment Panel-III; CVD, cardiovascular disease; apo B, apolipoprotein B; NMR, nuclear magnetic resonance; LDL-P, NMR-derived LDL particle number; IDL, intermediate density lipoprotein; Lp(a), lipoprotein(a); ITA, immunoturbidimetric assay; INA, immunonephelometric assay; LSP, Lipid Standardization Program; DCM, designated comparison method; CIMT, carotid intima media thickening; MetSyn, metabolic syndrome; VA-HIT, Veterans Affairs High-Density Lipoprotein Intervention Trial; OR, odds ratio; HR, hazards ratios; RR, relative risk; WHS, Women's Health Study; FOS, Framingham Offspring Study; HPS, Heart Protection Study; MOCE, major occlusive coronary event; VTE, venous thromboembolic disease; VTES, VTE Study; HTN, hypertension; NWLMDRL, Northwest Lipid Metabolism and Diabetes Research Laboratories.
Table 1. Summary of publications comparing apo B and LDL-P
for various outcomes in 25 clinical studies.

                           Parameter
                           association
                           (correlation
Study/authors/             of apo B to
type/duration              LDL-P, r, P)          apo B

Prediction of
CVD or events

  1 VA-HIT 2006;           On-trial              P = 0.0002
    Otvos et al.             values,
    (16) (Intervention       gemfibrozil vs
    with gemfibrozil;        placebo
    364 cases, 697           groups, P
    controls; 7 or
    12 months)
                           OR (95% CI) 1         1.12
                             SD at Baseline,     (0.99-1.27), NS
                             P                   (P = 0.08)

                           OR (95% CI) 1         1.07
                             SD at on-trial,     (0.94-1.23), NS
                             P (r = 0.56)        (P = 0.31) (On-
                                                 trial data at
                                                 12- month
                                                 visit)

  2 WHS 2002; Blake        Baseline              P = 0.002 2.43
    et al. (17)              concentrations,     (1.23-4.82), P
    (intervention with       cases vs            = 0.005
    aspirin and vitamin      controls, P
    E; 130 cases, 130
    controls; 3 years      Quartile 4 vs
    follow-up)               1, RR (95% CI),
                             P trend (r=
                             0.70, P <
                             0.001)

  3 WHS 2009; Mora et      Baseline              P < 0.001
    al. (18)                 concentrations,
    (intervention with       CVD vs non-
    aspirin and vitamin      CVD, P
    E; 1,015 CVD, 26,658
    non-CVD; 11 years      Quintile 5 vs         2.57 (1.98-
    follow-up)               1, HR (95% CI),     3.33),  P <
                             P linear trend      0.001
                             (r = 0.84)

  4 HPS 2012 (a);          HR (95% CI) 1SD at baseline, P
    Parish et al. (19)       MOCE
    (intervention with         Statin arm        1.23 (1.15-
    simvastatin and                                1.33), P <
                                                   0.001
    antioxidant
    vitamins; 20 021 men       Placebo arm       1.11 (1.05-
    and women; 5.3 years                           1.17), P <
    follow-up)                                     0.001

                             Revascularization
                               Statin arm        1.16
                                                   (1.08-1.23), P
                                                   < 0.001

                               Placebo arm       1.16
                                                   (1.10-1.23), P
                                                   < 0.001

                             Other cardiac
                                  event
                               Statin arm        1.06
                                                   (0.96-1.16), NS
                                                   (P < 0.9)

                               Placebo arm       1.08
                                                   (0.99-1.17), NS
                                                   (P < 0.1)

                             Ischemic stroke
                               Statin arm        1.11
                                                   (1.01-1.23), P
                                                   < 0.05

                               Placebo arm       1.01
                                                   (0.94-1.10), NS
                                                   (P < 0.95)

                             (r = 0.84)

  5 FOS 2007; Cromwell     Baseline sex-         No apo B data
    et al. (20)              specific
    (longitudinal            difference
    population study;        between study
    1140 men, 1626           participants
    women; median 14.8       with or without
    years follow-up)         CVD, P

                           HR (95% CI)
                             1 SD, P

  6 FOS 2007a;             HR (95% CI)           Men: 1.37
    Ingelsson et al.         1 SD, P               (1.20-1.57),
    (21) (longitudinal                             P < 0.001
    population study;
    1562 men, 1760                               Women: 1.38
    women; about 15                                (1.15-1.67),
    years follow-up)                               P < 0.001

  7 PEDCS 2003;            Baseline              P < 0.001
    Soedamah-Mutha et        concentrations,
    al. (22)                 cases vs
    (longitudinal study      controls,
    of 59 type 1             univariate, P
    diabetic patients        Multivariate, P     NS
    with CAD and 59
    controls; 10 years
    follow-up)

Presence of
carotid
atherosclerosis

  8 JHSS 2002; Post et     Association           P < 0.05
    al. (23)                 with increased
    (cross-sectional         carotid IMT on
    study of carotid IMT     univariate
    in 216 African-          analysis, P
    American siblings of
    patients with          Stepwise              NS (P = 0.08)
    premature CAD)           multivariate
                             logistic
                             regression to
                             predict
                             increased
                             carotid intima
                             media
                             thickening, P

  9 GOCADAN 2009;          Association           NS (P = 0.07)
    Masulli et al. (24)      with increased
    (cross-sectional         carotid IMT,
    study of CIMT in 656     P,or
    Alaska Eskimos)
                           plaque score by       NS (P = 0.09)
                             tertile, P

  10 SANDS 2009;           Change in             P < 0.0001
    Howard et al. (25)       aggressive
    (intervention trial      group vs
    of CIMT regression       standard group
    using aggressive vs      at 36 months, P
    standard lipid
    lowering in 418 type   Correlation to        NS (P = 0.07)
    2 diabetics; 3 years     CIMT regression
    follow-up)               by quartiles, P

                                                 Internal     Common

  11 DCCT-EDIC 2006;       Univariate            Men: P       P <
    Lyons et al. (26)        multiple            < 0.0005     0.0001
    (cross-sectional         regression
    study of CIMT in 540     analysis of         Women:       P <
    men and 428 women        CIMT vs             P < 0.01     0.05
    with type 1              parameter, P
    diabetes)
                           Multivariate          Men:         P =
                             multiple            P < 0.01     0.05
                             regression
                             analysis of         Women:       NS
                             CIMT vs             P = 0.02
                             parameter, P

                           Multivariate          Men: NS      NS
                             multiple            (P =         (P =
                             regression          0.07)        0.06)
                             analysis by set
                             of CIMT vs          Women:
                             parameter, P        NS           NS

  12 ARIC 2011; Virani     Association of
    et al. (27) (Cross-      parameters
    sectional study of       with:
    atherosclerosis by
    MRI in carotid           Total wall          P= 0.04
    arteries of 1670         volume, P
    participants)
                             Maximum wall        NS (P = 0.12)
                             thickness, P

                             Normalized wall     P= 0.02
                             index, P

                             SD of wall          NS (P = 0.11)
                             thickness, P

                           Presence of lipid rich core:

                             OR at 1 SD, P       1.08, NS (P = 0.34)

                             OR at 1 SD, P       1.04, NS (P = 0.68)

Prediction of MetSyn

  13 FOS 2006;             Sex-specific          Men: P < 0.0001
    Kathiresan et al.        difference          Women: P < 0.0001
    (28) (cross-             between study
    sectional population     participants
    study of MetSyn in       with or without
    2293 study               MetSyn, P
    participants)
                           Sex-specific          Men: P < 0.0001
                             trend analysis      Women: P < 0.0001
                             of association
                             with number of
                             MetSyn RF, P

  14 COMETS 2009;          Relation to           Rosuvatatin,
    Rosenson et al. (29)     statin, change        P < 0.001
    (Statin treatment in     from placebo
    257 MetSyn patients;     baseline value      Atorvastatin,
    12 weeks)                at 6 weeks, P         P < 0.001

  15 METSYN 2007;          Less than 3           Men: P < 0.05
    Clarenbach et al.        MetSyn RF vs 3      Women: NS
    (30) (cross-             or more RF, P
    sectional study of       Men, P Women
    274 adults with
    MetSyn)                Trend analysis        P = 0.039
                             of association
                             with number of
                             MetSyn RF, P
                           (r= 0.73, P <
                             0.0001)

Association with
diabetes mellitus or
diabetic complications

  16 DCCT-EDIC             Univariate            Men: P < 0.0001
    2003; Jenkins            multiple            Women: P < 0.005
    et al. (31)              regression          Both: P < 0.0001
    (cross-                  analysis of log
    sectional study          AER vs
    of diabetic              parameter by
    nephrophy in             cate-gories of
    540 men and 428          normo-, micro-
    women with type          and
    1 diabetes)              albuminuria, P
                             trend

                           Multivariate          Men: P < 0.01
                             multiple            Women: NS (P = 0.07)
                             regression          Both: P < 0.002
                             analysis as
                             above, P trend

                           Univariate            Both: P < 0.0005
                             multiple
                             regression
                             analysis of
                             creatinine
                             clearance vs
                             parameter by
                             categories of
                             normal,
                             elevated or
                             low, P

                           Multivariate          Both: P < 0.0005
                             multiple            Both: P < 0.0005
                             regression
                             analysis as
                             above, P

                                               Intensive   Conventional

  17 DCCT-EDIC             Univariate          P < 0.001    P < 0.001
    2003a; Jenkins           regression
    et al. (32)              analysis of sex
    (cross-                  by DCCT
    sectional study          treatment group
    of sex and               vs parameter, P
    glycemia in 540
    men and 428            Multivariate          NS           NS
    women with type          regression
    1 diabetes)              analysis of sex
                             by DCCT
                             treatment group
                             vs parameter, P

                           Correlation           Men: P <     P <
                             between             0.0001       0.0001
                             concurrent Hb       Women: P <   P <
                             by sex, P           0.0001       0.001

  18 GLOWS 2009;           Reduction in          P = 0.003
    Rosenson et al.          biomarker in
    (33) and Zieve           treated group
    etal. (34)               vs placebo
    (intervention            group at 12
    with colesevelam         weeks, P A1c
    or placebo in 56         and parameter
    type 2
    diabetics over
    12 weeks)

Association with plasma
lipids and lipoproteins

  19 SMART 2011;           ART Rx vs
    Baker et al.             no ART Rx
    (35)
    (intervention          At 2 months           P = 0.03
    with
    antiretroviral         At 6 months           NS (P = 0.60)
    therapy in 254         (r = 0.75,
    study                    P < 0.001)
    participants
    with HIV; 6
    months)

  20 ESTROGEN              Reduction in          P < 0.001
    1998; Giri               biomarker vs
    etal. (36)               baseline at 9
    (intervention            weeks, P
    with estrogen
    in 22 elderly
    men over 9
    weeks)

  21 HRT 1998;             Comparison of         NS
    Vadlamudi etal.          plasma
    (37) (cross-             parameters
    sectional study          between women
    of parameters            on or off
    in 8 women on            HRT, P
    and 10 not on
    HRT)

  22 FOS 2004;             Male/female           P = 0.001
    Freedman et al.          differences in      NS
    (38) (cross-             apo B
    sectional study          concentration
    of sex and age           and LDL
    effects on               particle
    lipoproteins in          number, P
    3266 study par-
    ticipants)             (r Men = 0.86;
                             r Women = 0.88)

  23 SIMVA 2001;           Reduction from
    Miller et al.            baseline
    (39)                     vs placebo:
    (intervention
    with                   40 mg                 P = 0.0003
    simvastatin for          simvastatin, P
    18 weeks; 20
    men and women)         80 mg                 P < 0.0001
                             simvastatin, P

  24 VTES 2005;            Baseline              NS (P =      P = 0.02
    Deguchi et al.           concentrations,     0.07)
    (40) (cross-             cases vs
    sectional study          controls, P
    of 49 cases
    with VTE from          OR (95% CI) for       2.1 (0.91-   2.2 (1.0-
    the Scripps              quartile 4            4.9),        4.9),
    Venous                   vs 1, P             NS (P =      P = 0.047
    Thrombosis                                     0.08)
    Registry age-
    matched with 49        OR (95% CI) for       1.9 (0.63-   3.6 (1.0-
    controls)                quartile 4            5.8),       16.0),
                             vs 1, P             NS (P =      P = 0.04
                                                   0.25)
                           Trend across          NS (P =      P = 0.03
                             quartiles, P          0.18)
                             trend

  25 WHS 2011;             Baseline              P < 0.001    P < 0.001
    Paynter et al.           concentrations,
    (41) (intervention       HTN vs non-
    with aspirin             HTN, P
    and vitamin E;
    4714 incident          Association of
    HTN, 12 858                parameter with
    non-HTN)                   incident HTN,
                               quintile 5 vs
                               quintile 1 OR
                               (95% CI) 1 SD,
                               P for trend

                             Unadjusted          2.23         2.82
                                                 (2.00-       (2.53-
                                                 2.48)        3.15)
                                                 P < 0.001    P < 0.001

                             Model 1             1.44         1.73
                                                 (1.28-       (1.54-
                                                 1.61)        1.95)
                                                 P < 0.001    P < 0.001
                             Model 2             1.39         1.63
                                                 (1.24-       (1.45-
                                                 1.56)        1.84)
                                                 P < 0.001    P < 0.001

                            Parameter
                            association
                            (correlation
Study/authors/              of apo B to
type/duration               LDL-P, r, P)          LDL-P

Prediction of
CVD or events

  1 VA-HIT 2006;            On-trial              P < 0.0001
    Otvos et al.              values,
    (16) (Intervention        gemfibrozil vs
    with gemfibrozil;         placebo
    364 cases, 697            groups, P
    controls; 7 or
    12 months)
                            OR (95% CI) 1         1.20 (1.05-1.37),
                              SD at Baseline,     P = 0.006
                              P

                            OR (95% CI) 1         1.28 (1.12-1.47),
                              SD at on-trial,     P = 0.0003
                              P (r = 0.56)        (On-trial data at
                                                  7-month visit)

  2 WHS 2002; Blake         Baseline              P < 0.001
    et al. (17)               concentrations,
    (intervention with        cases vs
    aspirin and vitamin       controls, P
    E; 130 cases, 130
    controls; 3 years       Quartile 4 vs         4.17 (1.96-
    follow-up)                1, RR (95% CI),     8.87), P <
                              P trend (r=         0.001
                              0.70, P <
                              0.001)

  3 WHS 2009; Mora et       Baseline              P < 0.001
    al. (18)                  concentrations,
    (intervention with        CVD vs non-
    aspirin and vitamin       CVD, P
    E; 1,015 CVD, 26,658
    non-CVD; 11 years       Quintile 5 vs         2.51 (1.91-3.30),
    follow-up)                1, HR (95% CI),     P < 0.001
                              P linear trend
                              (r = 0.84)

  4 HPS 2012 (a);           HR (95% CI) 1SD at baseline, P
    Parish et al. (19)        MOCE
    (intervention with          Statin arm        1.25
    simvastatin and                                 (1.16-1.35),
    antioxidant                                     P < 0.001
    vitamins; 20 021 men        Placebo arm       1.11
    and women; 5.3 years                            (1.05-1.17),
    follow-up)                                      P < 0.001

                              Revascularization
                                Statin arm        1.15
                                                    (1.07-1.23),
                                                    P < 0.001
                                Placebo arm       1.19
                                                    (1.13-1.26),
                                                    P < 0.001
                              Other cardiac
                                  event
                                Statin arm        1.08
                                                    (0.98-1.19),
                                                    NS (P < 0.9)
                                Placebo arm       1.10
                                                    (1.02-1.18),
                                                    P < 0.05
                              Ischemic stroke     1.06
                                Statin arm          (0.96-1.18),
                                                    NS (P < 0.9)
                                Placebo arm       1.01
                              (r = 0.84)            (0.93-1.08),
                                                    NS (P < 0.95)

  5 FOS 2007; Cromwell      Baseline sex-         Men: P < 0.0001
    et al. (20)               specific            Women: P <
    (longitudinal             difference          0.0001
    population study;         between study
    1140 men, 1626            participants
    women; median 14.8        with or without
    years follow-up)          CVD, P

                              HR (95% CI)         Men: 1.24
                              1 SD, P               (1.10-1.39),
                                                    P = 0.0005

                                                  Women: 1.33
                                                    (1.17-1.50),
                                                    P < 0.0001

                                                  Both: 1.28
                                                    (1.17-1.39),
                                                    P < 0.0001

  6 FOS 2007a;              HR (95% CI)           No LDL-P data
    Ingelsson et al.          1 SD, P
    (21) (longitudinal
    population study;
    1562 men, 1760
    women; about 15
    years follow-up)

  7 PEDCS 2003;             Baseline              P < 0.01
    Soedamah-Mutha et         concentrations,
    al. (22)                  cases vs
    (longitudinal study       controls,
    of 59 type 1              univariate, P
    diabetic patients         Multivariate, P     NS
    with CAD and 59
    controls; 10 years
    follow-up)

Presence of
carotid
atherosclerosis

  8 JHSS 2002; Post et      Association           P < 0.005
    al. (23)                  with increased
    (cross-sectional          carotid IMT on
    study of carotid IMT      univariate
    in 216 African-           analysis, P
    American siblings of
    patients with           Stepwise              P = 0.008
    premature CAD)            multivariate
                              logistic
                              regression to
                              predict
                              increased
                              carotid intima
                              media
                              thickening, P

  9 GOCADAN 2009;           Association           P = 0.037
    Masulli et al. (24)       with increased
    (cross-sectional          carotid IMT,
    study of CIMT in 656      P,or
    Alaska Eskimos)
                            plaque score by       NS (P = 0.432)
                              tertile, P

  10 SANDS 2009;            Change in             P =< 0.0001
    Howard et al. (25)        aggressive
    (intervention trial       group vs
    of CIMT regression        standard group
    using aggressive vs       at 36 months, P
    standard lipid
    lowering in 418 type    Correlation to        NS (P = 0.09)
    2 diabetics; 3 years      CIMT regression
    follow-up)                by quartiles, P

  11 DCCT-EDIC 2006;        Univariate            Men:        P <
    Lyons et al. (26)         multiple            P <         0.0005
    (cross-sectional          regression          0.001
    study of CIMT in 540      analysis of
    men and 428 women         CIMT vs             Women:      NS
    with type 1               parameter, P        P <         (P =
    diabetes)                                     0.0001      0.08)

                            Multivariate          Men:        NS
                              multiple            P < 0.01
                              regression
                              analysis of         Women:      NS
                              CIMT vs             P <
                              parameter, P        0.001

                            Multivariate          Men: P =    NS
                              multiple            0.01
                              regression
                              analysis by set     Women: P    NS (P
                              of CIMT vs          < 0.0001    = 0.08)
                              parameter, P

  12 ARIC 2011; Virani      Association of
    et al. (27) (Cross-       parameters
    sectional study of        with:
    atherosclerosis by
    MRI in carotid            Total wall          P = 0.006
    arteries of 1670          volume, P
    participants)
                              Maximum wall        P = 0.008
                              thickness, P

                              Normalized wall     P = 0.002
                              index, P

                              SD of wall          NS (P = 0.32)
                              thickness, P

                            Presence of lipid rich core:

                              OR at 1 SD, P       1.15, NS
                                                  (P = 0.08)

                              OR at 1 SD, P       1.07, NS
                                                  (P = 0.44)
Prediction of MetSyn

  13 FOS 2006;              Sex-specific          Men: P < 0.0001
    Kathiresan et al.         difference          Women: P < 0.0001
    (28) (cross-              between study
    sectional population      participants
    study of MetSyn in        with or without
    2293 study                MetSyn, P
    participants)
                            Sex-specific          Men: P < 0.0001
                              trend analysis      Women: P < 0.0001
                              of association
                              with number of
                              MetSyn RF, P

  14 COMETS 2009;           Relation to           Rosuvatatin,
    Rosenson et al. (29)      statin, change        P < 0.001
    (Statin treatment in      from placebo        Atorvastatin,
    257 MetSyn patients;      baseline value        P < 0.001
    12 weeks)                 at 6 weeks, P

  15 METSYN 2007;           Less than 3           Men: P < 0.05
    Clarenbach et al.         MetSyn RF vs 3      Women: NS
    (30) (cross-              or more RF, P
    sectional study of        Men, P Women
    274 adults with
    MetSyn)                 Trend analysis        P = 0.003
                              of association      (Conversion
                              with number of      of LDL-P to
                              MetSyn RF, P        apo B
                            (r= 0.73, P <         equivalents,
                              0.0001)             then
                                                  compared)

Association with
diabetes mellitus or
diabetic complications

  16 DCCT-EDIC              Univariate            Men: P <
    2003; Jenkins             multiple              0.005
    et al. (31)               regression          Women: P <
    (cross-                   analysis of log       0.05
    sectional study           AER vs              Both: P <
    of diabetic               parameter by          0.0001
    nephrophy in              cate-gories of
    540 men and 428           normo-, micro-
    women with type           and
    1 diabetes)               albuminuria, P
                              trend

                            Multivariate          Men: P <
                              multiple              0.05
                              regression          Women: NS
                              analysis as         Both: P <
                              above, P trend        0.05

                            Univariate            Both: P <
                              multiple              0.0002
                              regression
                              analysis of
                              creatinine
                              clearance vs
                              parameter by
                              categories of
                              normal,
                              elevated or
                              low, P

                            Multivariate          Age, sex,
                              multiple            diabetes
                              regression          duration,
                              analysis as         HTN, Hb A1c,
                              above, P            BMI, WHR,
                                                  DCCT
                                                  randomization
                                                  group

                                                Intensive   Conventional

  17 DCCT-EDIC              Univariate            P < 0.05    NS
    2003a; Jenkins            regression
    et al. (32)               analysis of sex
    (cross-                   by DCCT
    sectional study           treatment group
    of sex and                vs parameter, P
    glycemia in 540
    men and 428             Multivariate          NS          P <
    women with type           regression                      0.05
    1 diabetes)               analysis of sex
                              by DCCT
                              treatment group
                              vs parameter, P

                            Correlation           Men: P <    P <
                              between             0.0001      0.0001
                              concurrent Hb
                              by sex, P           Women: P    P <
                                                  < 0.0001    0.01

  18 GLOWS 2009;            Reduction in          P = 0.006
    Rosenson et al.           biomarker in
    (33) and Zieve            treated group
    etal. (34)                vs placebo
    (intervention             group at 12
    with colesevelam          weeks, P A1c
    or placebo in 56          and parameter
    type 2
    diabetics over
    12 weeks)

Association with plasma
lipids and lipoproteins

  19 SMART 2011;            ART Rx vs
    Baker et al.              no ART Rx
    (35)
    (intervention           At 2 months           NS (P = 0.096)
    with
    antiretroviral          At 6 months           NS (P = 0.79)
    therapy in 254          (r = 0.75,
    study                     P < 0.001)
    participants
    with HIV; 6
    months)

  20 ESTROGEN               Reduction in          P < 0.001
    1998; Giri                biomarker vs
    etal. (36)                baseline at 9
    (intervention             weeks, P
    with estrogen
    in 22 elderly
    men over 9
    weeks)

  21 HRT 1998;              Comparison of         NS
    Vadlamudi etal.           plasma
    (37) (cross-              parameters
    sectional study           between women
    of parameters             on or off
    in 8 women on             HRT, P
    and 10 not on
    HRT)

  22 FOS 2004;              Male/female           P = 0.001
    Freedman et al.           differences in      NS
    (38) (cross-              apo B
    sectional study           concentration
    of sex and age            and LDL
    effects on                particle
    lipoproteins in           number, P
    3266 study par-
    ticipants)              (r Men = 0.86;
                              r Women = 0.88)

  23 SIMVA 2001;            Reduction from
    Miller et al.             baseline
    (39)                      vs placebo:
    (intervention
    with                    40 mg                 P [less than or
    simvastatin for           simvastatin, P      equal to] 0.001
    18 weeks; 20
    men and women)          80 mg                 P [less than or
                              simvastatin, P      equal to] 0.001

  24 VTES 2005;             Baseline
    Deguchi et al.            concentrations,
    (40) (cross-              cases vs
    sectional study           controls, P
    of 49 cases
    with VTE from           OR (95% CI) for       Age, sex
    the Scripps               quartile 4
    Venous                    vs 1, P
    Thrombosis
    Registry age-
    matched with 49         OR (95% CI) for       BMI, factor vs
    controls)                 quartile 4            Leiden,
                              vs 1, P               prothrombin
                                                    20210A
                            Trend across
                              quartiles, P
                              trend

  25 WHS 2011;              Baseline              Model 1: age,
    Paynter et al.            concentrations,       smoking,
    (41) (intervention        HTN vs non-           fasting
    with aspirin              HTN, P                status, use
    and vitamin E;                                  of
    4714 incident           Association of          cholesterol-
    HTN, 12 858                 parameter with      lowering
    non-HTN)                    incident HTN,       medication,
                                quintile 5 vs       trial
                                quintile 1 OR       treatment
                                (95% CI) 1 SD,      assignment,
                                P for trend         hormone use,
                                                    race,
                                                    exercise,
                                                    alcohol use,
                                                    BMI,
                                                    diabetes,
                                                    education,
                                                    vegetable,
                                                    fruit, sodium
                                                    and grain
                                                    intake

                              Unadjusted          Model 2: adds
                                                    C-reactive
                              Model 1               protein,
                                                    homocysteine,
                              Model 2               fibrinogen,
                                                    soluble
                                                    intercellular
                                                    adhesion
                                                    molecule, Hb
                                                    [A.sub.1c]

                            Parameter
                            association
                            (correlation           Matching and/or
Study/authors/              of apo B to            adjustment
type/duration               LDL-P, r, P)           variables

Prediction of
CVD or events

  1 VA-HIT 2006;            On-trial               Age
    Otvos et al.              values,
    (16) (Intervention        gemfibrozil vs
    with gemfibrozil;         placebo
    364 cases, 697            groups, P
    controls; 7 or
    12 months)
                            OR (95% CI) 1          Treatment
                              SD at Baseline,      group, age,
                              P                    HTN, smoking,
                                                   BMI, (b)
                                                   diabetes

                            OR (95% CI) 1
                              SD at on-trial,
                              P (r = 0.56)

  2 WHS 2002; Blake         Baseline               Age, smoking,
    et al. (17)               concentrations,      treatment
    (intervention with        cases vs             group
    aspirin and vitamin       controls, P
    E; 130 cases, 130
    controls; 3 years       Quartile 4 vs
    follow-up)                1, RR (95% CI),
                              P trend (r=
                              0.70, P <
                              0.001)

  3 WHS 2009; Mora et       Baseline               Age,
    al. (18)                  concentrations,      randomized
    (intervention with        CVD vs non-          treatment
    aspirin and vitamin       CVD, P               assignment,
    E; 1,015 CVD, 26,658                           smoking
    non-CVD; 11 years       Quintile 5 vs          status,
    follow-up)                1, HR (95% CI),      menopausal
                              P linear trend       status,
                              (r = 0.84)           postmenopausal
                                                   hormone use,
                                                   BP, diabetes
                                                   mellitus, BMI

  4 HPS 2012 (a);           HR (95% CI) 1SD        Multiple baseline
    Parish et al. (19)      at baseline, P         covariates
    (intervention with
    simvastatin and           MOCE
    antioxidant                 Statin arm
    vitamins; 20 021 men        Placebo arm
    and women; 5.3 years      Revascularization
    follow-up)                  Statin arm
                                Placebo arm
                              Other cardiac event
                                Statin arm
                                Placebo arm
                              Ischemic stroke
                                Statin arm
                                Placebo arm
                              (r = 0.84)

  5 FOS 2007; Cromwell      Baseline sex-          Age, SBP,
    et al. (20)               specific             DBP, smoking,
    (longitudinal             difference           lipid
    population study;         between study        medication
    1140 men, 1626            participants         use
    women; median 14.8        with or without
    years follow-up)          CVD, P

                              HR (95% CI)
                              1 SD, P

  6 FOS 2007a;              HR (95% CI)            Age, SBP,
    Ingelsson et al.          1 SD, P              antihypertensive
    (21) (longitudinal                             treatment,
    population study;                              diabetes,
    1562 men, 1760                                 smoking
    women; about 15
    years follow-up)

  7 PEDCS 2003;             Baseline
    Soedamah-Mutha et         concentrations,
    al. (22)                  cases vs
    (longitudinal study       controls,
    of 59 type 1              univariate, P
    diabetic patients         Multivariate, P      6 Models
    with CAD and 59
    controls; 10 years
    follow-up)

Presence of
carotid
atherosclerosis

  8 JHSS 2002; Post et      Association            Age, sex,
    al. (23)                  with increased       duration of
    (cross-sectional          carotid IMT on       diabetes
    study of carotid IMT      univariate
    in 216 African-           analysis, P
    American siblings of
    patients with           Stepwise               Age, male
    premature CAD)            multivariate         sex, SBP
                              logistic
                              regression to
                              predict
                              increased
                              carotid intima
                              media
                              thickening, P

  9 GOCADAN 2009;           Association
    Masulli et al. (24)       with increased
    (cross-sectional          carotid IMT,
    study of CIMT in 656      P,or
    Alaska Eskimos)
                            plaque score by        Age, sex,
                              tertile, P           BMI, SBP,
                                                   current
                                                   smoking

  10 SANDS 2009;            Change in              CIMT, LDL-C,
    Howard et al. (25)        aggressive           SBP values
    (intervention trial       group vs
    of CIMT regression        standard group
    using aggressive vs       at 36 months, P
    standard lipid
    lowering in 418 type    Correlation to
    2 diabetics; 3 years      CIMT regression
    follow-up)                by quartiles, P

  11 DCCT-EDIC 2006;        Univariate             Raw data
    Lyons et al. (26)         multiple
    (cross-sectional          regression
    study of CIMT in 540      analysis of
    men and 428 women         CIMT vs
    with type 1               parameter, P
    diabetes)
                            Multivariate           Age, duration
                              multiple             of diabetes,
                              regression           HbA1c, BMI,
                              analysis of          AER, HTN,
                              CIMT vs              smoking, DCCT
                              parameter, P         randomization
                                                   group

                            Multivariate
                              multiple
                              regression
                              analysis by set
                              of CIMT vs
                              parameter, P

  12 ARIC 2011; Virani      Association of         Fully
    et al. (27) (Cross-       parameters           adjusted, see
    sectional study of        with:                Fig. 1,
    atherosclerosis by                             footnote b
    MRI in carotid            Total wall
    arteries of 1670          volume, P
    participants)
                              Maximum wall
                              thickness, P

                              Normalized wall
                              index, P

                              SD of wall
                              thickness, P

                            Presence of lipid rich core:

                              OR at 1 SD, P        Fully
                                                   adjusted

                              OR at 1 SD, P        Fully
                                                   adjusted +
                                                   wall
                                                   thickness

Prediction of MetSyn

  13 FOS 2006;              Sex-specific           Age
    Kathiresan et al.         difference
    (28) (cross-              between study
    sectional population      participants
    study of MetSyn in        with or without
    2293 study                MetSyn, P
    participants)
                            Sex-specific           Age
                              trend analysis
                              of association
                              with number of
                              MetSyn RF, P

  14 COMETS 2009;           Relation to            Treatment,
    Rosenson et al. (29)      statin, change       study center,
    (Statin treatment in      from placebo         baseline
    257 MetSyn patients;      baseline value       value
    12 weeks)                 at 6 weeks, P

  15 METSYN 2007;           Less than 3
    Clarenbach et al.         MetSyn RF vs 3
    (30) (cross-              or more RF, P
    sectional study of        Men, P Women
    274 adults with
    MetSyn)                 Trend analysis
                              of association
                              with number of
                              MetSyn RF, P
                            (r= 0.73, P <
                              0.0001)

Association with
diabetes mellitus or
diabetic complications

  16 DCCT-EDIC              Univariate             Raw data
    2003; Jenkins             multiple
    et al. (31)               regression
    (cross-                   analysis of log
    sectional study           AER vs
    of diabetic               parameter by
    nephrophy in              cate-gories of
    540 men and 428           normo-, micro-
    women with type           and
    1 diabetes)               albuminuria, P
                              trend

                            Multivariate           Age, (sex for
                              multiple             total
                              regression           cohort),
                              analysis as          diabetes
                              above, P trend       duration,
                                                   HTN, Hb
                                                   [A.sub.1c],
                                                   BMI, WHR,
                                                   DCCT
                                                   randomization
                                                   group

                            Univariate
                              multiple
                              regression
                              analysis of
                              creatinine
                              clearance vs
                              parameter by
                              categories of
                              normal,
                              elevated or
                              low, P

                            Multivariate
                              multiple
                              regression
                              analysis as
                              above, P

                                                   Raw data

  17 DCCT-EDIC              Univariate             Raw data
    2003a; Jenkins            regression
    et al. (32)               analysis of sex
    (cross-                   by DCCT
    sectional study           treatment group
    of sex and                vs parameter, P
    glycemia in 540
    men and 428             Multivariate           Age, duration
    women with type           regression             of diabetes,
    1 diabetes)               analysis of sex        Hb [A.sub.1c],
                              by DCCT                BMI, AER, WHR,
                              treatment group        HTN, smoking,
                              vs parameter, P        DCCT
                                                     randomization
                                                     group

                            Correlation            Age, duration
                              between                of diabetes,
                              concurrent Hb          BMI, AER,
                              by sex, P              WHR, HTN,
                                                     smoking, DCCT
                                                     randomization
                                                     group.

  18 GLOWS 2009;            Reduction in           Raw data
    Rosenson et al.           biomarker in
    (33) and Zieve            treated group
    et al. (34)               vs placebo
    (intervention             group at 12
    with colesevelam          weeks, P
    or placebo in 56
    type 2
    diabetics over
    12 weeks)

Association with plasma
lipids and lipoproteins

  19 SMART 2011;            ART Rx vs
    Baker et al.              no ART Rx
    (35)
    (intervention           At 2 months
    with
    antiretroviral          At 6 months
    therapy in 254          (r = 0.75,
    study                     P < 0.001)
    participants
    with HIV; 6
    months)

  20 ESTROGEN               Reduction in           Raw data
    1998; Giri                biomarker vs
    etal. (36)                baseline at 9
    (intervention             weeks, P
    with estrogen
    in 22 elderly
    men over 9
    weeks)

  21 HRT 1998;              Comparison of          HRT use
    Vadlamudi etal.           plasma
    (37) (cross-              parameters
    sectional study           between women
    of parameters             on or off
    in 8 women on             HRT, P
    and 10 not on
    HRT)

  22 FOS 2004;              Male/female            Age adjusted
    Freedman et al.           differences in       Age and lipid
    (38) (cross-              apo B                  adjusted
    sectional study           concentration
    of sex and age            and LDL
    effects on                particle
    lipoproteins in           number, P
    3266 study par-
    ticipants)              (r Men = 0.86;
                              r Women = 0.88)

  23 SIMVA 2001;            Reduction from
    Miller et al.             baseline
    (39)                      vs placebo:
    (intervention
    with                    40 mg
    simvastatin for           simvastatin, P
    18 weeks; 20
    men and women)          80 mg
                              simvastatin, P

  24 VTES 2005;             Baseline
    Deguchi et al.            concentrations,
    (40) (cross-              cases vs
    sectional study           controls, P
    of 49 cases
    with VTE from           OR (95% CI) for
    the Scripps               quartile 4
    Venous                    vs 1, P
    Thrombosis
    Registry age-
    matched with 49         OR (95% CI) for
    controls)                 quartile 4
                              vs 1, P

                            Trend across
                              quartiles, P
                              trend

  25 WHS 2011;              Baseline
    Paynter et al.            concentrations,
    (41) (intervention        HTN vs non-
    with aspirin              HTN, P
    and vitamin E;
    4714 incident           Association of
    HTN, 12 858                 parameter with
    non-HTN)                    incident HTN,
                                quintile 5 vs
                                quintile 1 OR
                                (95% CI) 1 SD,
                                P for trend

                              Unadjusted

                              Model 1

                              Model 2

(a) For study 4 HPS 2012, P values were derived by the
authors from [[chi square].sub.1] values given in the publication.

(b) BMI, body mass index; NS, not significant; BP, blood
pressure; SBP, systolic BP; DBP, diastolic BP; PEDCS,
Pittsburgh Epidemiology of Diabetes Complications Study;
JHSS, Johns Hopkins Siblings Study; GOCADAN, Genetics
Coronary Artery Disease in Alaska Natives; SANDS, Stop
Atherosclerosis in Native Diabetics Study; DCCT-EDIC,
Diabetes Control and Complications Trial-Epidemiology of
Diabetes Interventions and Complications study; AF
Atherosclerosis Risk in Communities; COMETS, Comparative
Study with Rosuvastatin in Subjects with Metabolic Syndrome;
METSYN, Study of Metabolic Syndrome; RF, risk factors; AER,
albumin excretion rate; Hb [A.sub.1c], hemoglo [A.sub.1c]; WHR,
waist-hip ratio; GLOWS, Glucose-Lowering Effect of WelChol
Study; SMART, Strategies for Management of Antiretroviral
Therapy; Rx, pharmacological treatment; ESTROGEN, study of
estrogen in elderly men; H study of hormone replacement
therapy on lipoproteins; or hormone replacement therapy;
SIMVA, study of simvastatin in mixed hyperlipidemia.

Table 2. Categorizations of comparisons of apo B and
LDL-P in reviewed publications.

                                       Only apo B      Only LDL-P
                                      statistically   statistically
                                      significant,    significant,
                                        LDL-P not       apo B not
Study/authors                          significant     significant

Clinical parameter or outcome
Prediction of CVD or events
  1 VA-HIT 2006 Otvos et al. (16)
    Gemfibrozil vs placebo
    OR baseline                                             X
    OR on-trial                                             X
  2 WHS 2002 Blake et al. (17)
    Baseline concentrations
    Quartile 4 vs 1, RR
  3 WHS 2009 Mora et al. (18)
    Baseline concentrations
    Quintile 5 vs 1, HR
  4 HPS 2012 Parish et al. (19)
    MOCE
      Statin arm
      Placebo arm
    Revascularization
      Statin arm
      Placebo arm
    Other cardiac event
      Statin arm
      Placebo arm                                           X
    Ischemic stroke
      Statin arm                            X
      Placebo arm
  5 FOS 2007 Cromwell et al.
     (20)/6 FOS 2007a Ingelsson
      et al. (21)
      Relation to future
        CVD, HR, men
      Relation to future
        CVD, HR, women
  7 PEDCS 2003 Soedamah-
        Mutha et al. (22)
      Baseline concentrations,
        UV (a)
      Baseline concentrations, MV
Presence of carotid
atherosclerosis
  8 JHSS 2002 Post et al. (23)
    Association with
      carotid IMT, UV
    Association with
      carotid IMT, MV                                       X
  9 GOCADAN 2009 Masulli
      et al. (24)
    Association with carotid IMT                            X
    Association with carotid
      plaque score
  10 SANDS 2009 Howard et al. (25)
    Response to therapy
    Correlation to CIMT
      regression by quartiles
  11 DCCT/EDIC 2006
         Lyons et al. (26)
    ICA, CIMT vs parameter,
      UV, men
    ICA, CIMT vs parameter,
      UV, women
    CCA, CIMT vs parameter,
      UV, men
    CCA, CIMT vs parameter,
      UV, women                             X
    ICA, CIMT vs parameter,
      MV, men
    ICA, CIMT vs parameter,
      MV, women
    CCA, CIMT vs parameter,
      MV, men                               X
    CCA, CIMT vs parameter,
      MV, women
    ICA, CIMT vs parameter,
      MV set, men                                           X
    ICA, CIMT vs parameter,
      MV set, women                                         X
    CCA, CIMT vs parameter,
      MV set, men
    CCA, CIMT vs parameter,
      MV set, women
  12 ARIC 2011 Virani etal. (27)
     Total wall volume
     Maximum wall thickness                                 X
     Normalized wall index
     SD of wall thickness
     OR, lipid-rich core,
       fully adjusted
     OR, lipid-rich core,
       fully adjusted
       + wall thickness
Prediction of MetSyn
  13 FOS 2006 Kathiresan
       et al. (28)
    Sex-specific difference, men
    Sex-specific difference, women
    Trend with number of risk
      factors, men
    Trend with number of risk
      factors, women
  14 COMETS 2009 Rosenson
      et al. (29)
    Change from baseline,
      rosuvastatin
    Change from baseline,
      atorvastatin
  15 METSYN 2007 Clarenbach
      et al. (30)
    Three or more risk
      factors, men
    Three or more risk
      factors, women
    Trend with number of
      risk factors
Association with
diabetes mellitus or
diabetic complications
  16 DCCT/EDIC 2003 Jenkins
       et al. (31)
    AER vs parameter
      by category, UV, men
    AER vs parameter by
      category, UV, women
    AER vs parameter by
      category, UV, both
    AER vs parameter by
      category, MV, men
    AER vs parameter by
      category, MV, women
    AER vs parameter by
      category, MV, both
    Creatinine clearance vs
      parameter, UV, both
    Creatinine clearance vs
      parameter, MV, both

  17 DCCT/EDIC 2003a
       Jenkins et al. (32)
    Treatment group vs parameter,
      UV, intensive
    Treatment group vs parameter,
      UV, conventional                      X
    Treatment group vs parameter,
      MV, intensive
    Treatment group vs parameter,
      MV, conventional                                      X
    Hb [A1.sub.c] vs parameter
      by sex, UV, men
    Hb [A1.sub.c] vs parameter
      by sex, UV, women
    Hb [A1.sub.c] vs parameter
      by sex, MV, men
    Hb [A1.sub.c] vs parameter
      by sex, MV, women
  18 GLOWS 2009 Rosenson et
       al. and Zieve et al.
       (33,34)
     Colesevelam Rx
Association with plasma
lipids and lipoproteins
  19 SMART 2011 Baker et al. (35)
     ART Rx at 2 months                     X
     ART Rx at 6 months
  20 ESTROGEN 1998 Giri et al. (36)
     Estrogen Rx
  21 HRT 1998 Vadlamudi et al. (37)
     HRT Rx
  22 FOS 2004 Freedman et al. (38)
     Age adjusted
     Age and lipid adjusted
  23 SIMVA 2001 Miller et al. (39)
     40 mg Rx
     80 mg Rx
Prediction of miscellaneous events
  24 VTES 2005 Deguchi et al. (40)
     Baseline concentrations                                X
     OR, quartile 4 vs 1, UV                                X
     OR, quartile 4 vs 1, MV                                X
     Trend across quartiles                                 X
  25 WHS 2011 Paynteretal. (41)
     Baseline concentrations
     OR, quintile 5 vs 1,
       Unadjusted
     OR, quintile 5 vs 1, Model 1
     OR, quintile 5 vs 1, Model 2

                                          Both           Neither
                                      statistically   statistically
Study/authors                          significant     significant

Clinical parameter or outcome
Prediction of CVD or events
  1 VA-HIT 2006 Otvos et al. (16)
    Gemfibrozil vs placebo                  X
    OR baseline
    OR on-trial
  2 WHS 2002 Blake et al. (17)
    Baseline concentrations                 X
    Quartile 4 vs 1, RR                     X
  3 WHS 2009 Mora et al. (18)
    Baseline concentrations                 X
    Quintile 5 vs 1, HR                     X
  4 HPS 2012 Parish et al. (19)
    MOCE
      Statin arm                            X
      Placebo arm                           X
    Revascularization
      Statin arm                            X
      Placebo arm                           X
    Other cardiac event
      Statin arm                                            X
      Placebo arm
    Ischemic stroke
      Statin arm
      Placebo arm                                           X
  5 FOS 2007 Cromwell et al.
     (20)/6 FOS 2007a Ingelsson
      et al. (21)
      Relation to future
        CVD, HR, men                        X
      Relation to future
        CVD, HR, women                      X
  7 PEDCS 2003 Soedamah-
        Mutha et al. (22)
      Baseline concentrations,
        UV (a)                              X
      Baseline concentrations, MV                           X
Presence of carotid
atherosclerosis
  8 JHSS 2002 Post et al. (23)
    Association with
      carotid IMT, UV                       X
    Association with
      carotid IMT, MV
  9 GOCADAN 2009 Masulli
      et al. (24)
    Association with carotid IMT
    Association with carotid
      plaque score                                          X
  10 SANDS 2009 Howard et al. (25)
    Response to therapy                     X
    Correlation to CIMT
      regression by quartiles                               X
  11 DCCT/EDIC 2006
         Lyons et al. (26)
    ICA, CIMT vs parameter,                 X
      UV, men
    ICA, CIMT vs parameter,
      UV, women                             X
    CCA, CIMT vs parameter,
      UV, men                               X
    CCA, CIMT vs parameter,
      UV, women
    ICA, CIMT vs parameter,
      MV, men                               X
    ICA, CIMT vs parameter,
      MV, women                             X
    CCA, CIMT vs parameter,
      MV, men
    CCA, CIMT vs parameter,
      MV, women                                             X
    ICA, CIMT vs parameter,
      MV set, men
    ICA, CIMT vs parameter,
      MV set, women
    CCA, CIMT vs parameter,
      MV set, men                                           X
    CCA, CIMT vs parameter,
      MV set, women                                         X
  12 ARIC 2011 Virani etal. (27)
     Total wall volume                      X
     Maximum wall thickness
     Normalized wall index                  X
     SD of wall thickness                                   X
     OR, lipid-rich core,
       fully adjusted                                       X
     OR, lipid-rich core,
       fully adjusted
       + wall thickness                                     X
Prediction of MetSyn
  13 FOS 2006 Kathiresan
       et al. (28)
    Sex-specific difference, men            X
    Sex-specific difference, women          X
    Trend with number of risk
      factors, men                          X
    Trend with number of risk
      factors, women                        X
  14 COMETS 2009 Rosenson
      et al. (29)
    Change from baseline,
      rosuvastatin                          X
    Change from baseline,
      atorvastatin                          X
  15 METSYN 2007 Clarenbach
      et al. (30)
    Three or more risk
      factors, men                          X
    Three or more risk
      factors, women                                        X
    Trend with number of
      risk factors                          X
Association with
diabetes mellitus or
diabetic complications
  16 DCCT/EDIC 2003 Jenkins
       et al. (31)
    AER vs parameter
      by category, UV, men                  X
    AER vs parameter by
      category, UV, women                   X
    AER vs parameter by
      category, UV, both                    X
    AER vs parameter by
      category, MV, men                     X
    AER vs parameter by
      category, MV, women                                   X
    AER vs parameter by
      category, MV, both                    X
    Creatinine clearance vs
      parameter, UV, both                   X
    Creatinine clearance vs
      parameter, MV, both                   X
  17 DCCT/EDIC 2003a
       Jenkins et al. (32)
    Treatment group vs parameter,
      UV, intensive                         X
    Treatment group vs parameter,
      UV, conventional
    Treatment group vs parameter,
      MV, intensive                                         X
    Treatment group vs parameter,
      MV, conventional
    Hb [A1.sub.c] vs parameter
      by sex, UV, men                       X
    Hb [A1.sub.c] vs parameter
      by sex, UV, women                     X
    Hb [A1.sub.c] vs parameter
      by sex, MV, men                       X
    Hb [A1.sub.c] vs parameter
      by sex, MV, women                     X
  18 GLOWS 2009 Rosenson et
       al. and Zieve et al.
       (33,34)
     Colesevelam Rx                         X
Association with plasma
lipids and lipoproteins
  19 SMART 2011 Baker et al. (35)
     ART Rx at 2 months
     ART Rx at 6 months                                     X
  20 ESTROGEN 1998 Giri et al. (36)
     Estrogen Rx                            X
  21 HRT 1998 Vadlamudi et al. (37)
     HRT Rx                                                 X
  22 FOS 2004 Freedman et al. (38)
     Age adjusted                           X
     Age and lipid adjusted                                 X
  23 SIMVA 2001 Miller et al. (39)
     40 mg Rx                               X
     80 mg Rx                               X
Prediction of miscellaneous events
  24 VTES 2005 Deguchi et al. (40)
     Baseline concentrations
     OR, quartile 4 vs 1, UV
     OR, quartile 4 vs 1, MV
     Trend across quartiles
  25 WHS 2011 Paynteretal. (41)
     Baseline concentrations                X
     OR, quintile 5 vs 1,
       Unadjusted                           X
     OR, quintile 5 vs 1, Model 1           X
     OR, quintile 5 vs 1, Model 2           X

(a) UV, univariate; MV, multivariate; ICA, internal carotid
artery, CCA, common carotid artery; other nonstandard
abbreviations not defined in the text are defined in the
Table 1 footnote.

Table 3. Comparison of apo B immunoturbidometric assay/
immunonephelometric assay and NMR-LDL-P methodologies.

                       apo B                  NMR-LDL-P

Assay methods          Multiple vendors,      Proprietary
                       not all standardized   in-house, not
                                              standardized

Calibration            Reference material     Not calibrated; uses
                       (SP3-07, SP3-08),      proprietary library
                       performed by end       of isolated
                       user using kit         lipoprotein
                       calibrators            fractions to set
                                              concentrations

Entity measured        Antigen-antibody       Terminal methyl
                       complex                groups on
                                              lipoprotein-
                                              associated lipids

Precision, within      Lab dependent          2%-4%
assay (%CV)

Precision, between     Lab dependent, CV      2%-4%
assay (%CV)            4.1%-11.6%

Precision, mean        Lab dependent, 7.2%    NA
within method,         (CAP PTa data)
between laboratory
(%CV)

Samples                Destructive            Destructive

Fed or fasted          Either                 Either

Samples frozen at      Stable for years       Stable for years
-70[degrees]C

Stability in ongoing   Can change over        Probably stable over
clinical studies       time, depends on       time, requires
                       manufacturer           internal
                       diligence              surveillance

Information reported   apo B concentration    Particle number and
                                              size, lipid
                                              concentrations

Standardization        Yes, performed by      No
program                manufacturer

Performance criteria   None                   None

Potential problems     Antibody recognition   Identifies particle
                       of epitopes on         only by size, i.e.,
                       variant LDLs, e.g.     includes IDL and
                       small, complex         Lp(a) in LDL-P
                       formation rate,
                       turbidity vs
                       detergent effect,
                       may include VLDL,
                       IDL, and Lp(a)

Availability of test   Runs in typical        Run only at
                       clinical lab on        LipoScience on
                       common                 specialized
                       instrumentation        instrumentation

Growth                 Readily scalable;      Limited by capacity
                       numerous vendors and   of central lab
                       applications for
                       most analyzers

Cost                   Modest ([congruent     Modest to high
                       to] $17)               ([congruent to] $30-$40)

(a) CAP PT, College of American Pathologists Proficiency
Testing Program; NA, not applicable or available.
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Title Annotation:Special Report
Author:Cole, Thomas G.; Contois, John H.; Csako, Gyorgy; McConnell, Joseph P.; Remaley, Alan T.; Devaraj, S
Publication:Clinical Chemistry
Article Type:Report
Geographic Code:1USA
Date:May 1, 2013
Words:13011
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