Is chronic kidney disease comparable to diabetes as a coronary artery disease risk factor?

Background: Chronic kidney disease (CKD) is one of the known risk factors for coronary heart disease (CHD). Though electrocardiograms (ECGs) have limited accuracy in determining the true prevalence of CHD, we wondered whether CKD and diabetes mellitus (DM) controlled for hypertension (HTN), had similar prevalences of ECG abnormalities that could reflect underlying coronary heart disease.

Method: Data were collected for 5,942 men and women aged 30 to 69 years in the Tehran Lipid and Glucose Study (TLGS), a cross-sectional phase of a large epidemiologic study first initiated in 1999. ECG findings of all subjects were coded according to Minnesota ECG coding criteria. The Whitehall criteria for abnormal ECG findings that could represent ischemia were utilized. Creatinine clearance (Crcl) was estimated using the Cockroft-Gault equation and diabetes was defined according to the American Diabetic Association (ADA) criteria. Subjects with moderate CKD and without DM were compared with the patients with DM without CKD. HTN prevalence was similar. The analysis was performed for all Whitehall ECG ischemia abnormalities combined, and separately for pathologic Q waves.

Results: In spite of an overall similar prevalence of smoking, and a lower incidence of dyslipidemia and HTN, moderate CKD patients had a higher prevalence of Whitehall criteria abnormal ECG findings compared with the patients with DM. Over 19% of patients with CKD had abnormal ECG findings while 14.7% of diabetic patients had abnormal ECGs (P = 0.02). The prevalence of Q waves was 11.5% in patients with CKD and 10.8% in patients with DM. In an age-matched subgroup of patients with DM and no CKD, the prevalence of ECG abnormalities was 19.3%, similar to the patients with moderate CKD and no DM (19.7%) (P = 0.9). The prevalence of pathologic Q waves in an age-matched group was 11.45%, compared with 11.5%, respectively.

Conclusion: Moderate CKD is a major risk factor for the development of the Whitehall ECG criteria which have been associated with ischemic heart disease. The importance of CKD as a risk factor for ECG abnormalities is comparable with DM. Patients with moderate CKD probably are candidates for aggressive CHD risk modification.

Key Words: chronic kidney disease, diabetes, coronary heart disease

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Chronic renal failure is an important risk factor for coronary artery disease and coronary artery disease-related mortality and morbidity. (1) According to the US Renal Data System, at least 40% of patients initiating dialysis have established coronary artery disease (CAD). (2,3) Annually, 10% of end stage renal disease (ESRD) patients require hospitalization for acute coronary syndromes. (4) Dialysis patients aged 20 to 44 years have a 150 times higher cardiovascular death rate than aged-match controls. (5) ESRD patients undergoing coronary artery bypass grafting (CABG) have an 8 to 10% thirty-day mortality. (6)

A high rate of coronary artery disease-related morbidity and mortality of patients with chronic kidney disease (CKD) not yet requiring dialysis has also been described. (7) Risk factors like diabetes, hypertension, hyperlipidemia and advanced age are present in patients with chronic kidney disease. Chronic kidney disease is an independent risk factor however, and for each 10 mL/min per 1.73 [m.sup.2] decrease in the glomerular filtration rate, there is a 5% higher cardiovascular risk. (8) Even minor degrees of renal failure in patients with known risk factors for coronary artery disease are independently associated with the development of cardiovascular disease. (9,10)

According to the National Health and Nutrition Examination Survey III (NHANES), as many as 6.6 million United States residents above the age of 60 have a glomerular filtration rate (GFR) of less than 60 mL/min/1.73 [m.sup.2,8] and 4.3% of the population are estimated to have moderate CKD (stage III CKD with a GFR between 30 and 60 mL/min per 1.73 [m.sup.2]). (11-13)

In spite of strong associations between CKD and CAD, the importance of CKD as a CAD risk factor has not been as highlighted as it has in diabetes mellitus (DM). (14,15) In this study, we compared CKD and DM as a CAD risk factor. We hypothesized that moderate CKD and DM would be equally associated with Whitehall-defined ECG ischemia criteria. We utilized the Tehran Lipid and Glucose Study (TLGS) data on 5,942 patients and investigated the prevalence of defined electrocardiographic (ECG) evidence for ischemia in patients with CKD compared with patients with diabetes mellitus.

Methods

Tehran Lipid and Glucose Study Design

Details of the Tehran Lipid and Glucose Study (TLGS), its rationale and design have been published elsewhere. (16-18) In brief, TLGS is a longitudinal study which has been conducted within the framework of a National Project of the Scientific Research Council and includes an assessment of cardiovascular risk factors and disease in residents of Tehran district 13.

The first phase is a cross-sectional population study or a baseline examination survey. It has been designed to measure the prevalence of risk factors including dyslipoproteinemia, hyperglycemia, obesity, smoking, and hypertension. Designated residents were sent an invitation requesting their participation. The crude response rate in the TLGS participants was approximately 57.5%. The reasons for no response have been investigated and there was no significant difference between responders and nonresponders. (17)

The data were collected through individual interviews and physical examinations and were directly stored in a computer database. (19) Selected people were invited for an interview and medical examination to the Lipid and Glucose Study Unit (LGSU). They were first familiarized by social workers at home with the study objectives and were invited to participate in the study at the second visit. They were asked to sign a written consent and bring it to the LGSU following the first visit. The data included demographics and medications; physical examination for blood pressure, pulse rate, and anthropometric measurements; laboratory measurements of lipid profiles, fasting blood sugar, 2-hour postglucose challenge, thyroid profile, kidney function tests; and for subjects older than age 30, ECGs. (16-18)

ECG and Definition of ECG-defined Ischemia, Diabetes Mellitus, Chronic Kidney Disease and Hypertension

A 12-lead rest ECG was recorded for each individual aged [greater than or equal to]30 years by two trained technicians, according to a standard recording protocol developed by the University of Minnesota School of Public Health, (20) using a PC-ECG 1,200 machine (models S and M for DOS, version 4.07, Cardioscan NV/SA, Brussels, Belgium). Two trained physicians coded the ECGs independently, according to the Minnesota codes, using a measuring loupe specially manufactured by the University of Minnesota. (21) To ensure quality, a third trained physician recoded 10% of the ECGs and all the data were doubly entered. (22) According to the Whitehall criteria, abnormal ECG findings that could potentially be representative of ischemic heart disease were defined as one or more of the following Minnesota code items: Q/Qs waves (1.1-1.3); ST depressions (4.1-4.4); T-wave inversion or flattening (5.1-5.3); or left bundle branch block (7.1). DM was defined according to the American Diabetes Association and included the patients who were taking glycemic agents. (23) HTN was defined according to the JNC VII criteria (24) and included the patients who were taking antihypertensive medications. Crcl was estimated using the Cockroft-Gault equation.

Crcl = [(140 - age in years) X (body weight in kilograms)]/(72 X serum creatinine in milligrams per deciliter). This value is multiplied by 0.85 in women.

The classification of CKD by stages was done according to the Kidney Disease Outcomes Quality Initiative (K/DOQI) criteria as below: (12)

Stage 1: Normal GFR (greater than 90 ml/min per 1.73 [m.sup.2]) and persistent albuminuria.

Stage 2: A GFR between 60 to 89 mL/min per 1.73 [m.sup.2] and persistent albuminuria.

Stage 3: A GFR between 30 and 59 ml/min per 1.73 [m.sup.2].

Stage 4: A GFR between 15 and 29 ml/min per 1.73 [m.sup.2].

Stage 5: A GFR of less than 15 ml/min per 1.73 [m.sup.2] or end-stage renal disease.

Measurement of Other Risk Factors

Total cholesterol (TC) and triglycerides (TGs) were assayed using enzymatic calorimetric tests with cholesterol esterase and cholesterol oxidase and glycerol phosphate oxidase, respectively. HDL-C was measured after precipitation of the apolipoprotein B containing lipoproteins with phosphotungstic acid. LDL-C was calculated from the serum TC, TG, and HDL-C concentrations expressed in mg/dL using the Friedewald formula if the TG concentration was lower than 400 mg/dL. (25) Body mass index was calculated by dividing the weight in kilograms by the square of height in meters. Cerebrovascular accident was defined according to the past medical history and based on the answer of the subject to the relevant question. Present smoker was defined by smoking at least once a day. (26)

Statistical Analysis

Subjects aged [greater than or equal to]30 years were initially selected and categorized into diabetic and nondiabetic groups. They also were divided into two subgroups based on their ECG (22): 1) probable/possible evidence for ischemic disease; or 2) no evidence for ischemic disease. ECG data for 6,422 subjects (2,550 men and 3,393 women) aged 30 or older were collected and analyzed. Four hundred and eighty-nine subjects who had data missing on weight, creatinine, blood glucose, lipid profile or blood pressure were excluded. The final study population consisted of 5,942 subjects. SPSS 10.0 statistical software package (SPSS Inc., Chicago, IL) was used in the statistical analysis. Statistical significance was set at P [less than or equal to] 0.05. Difference for continuous variables was assessed by using the student t test, whereas difference for categorical variables was assessed with the [chi square] test. Logistic regression analysis was done to calculate odds ratios.

Results

Baseline Characteristics

In 5,942 studied subjects, the mean age was 48.6 [+ or -] 13.3 and 46.9 [+ or -] 11.9 years in men and women, respectively. Of the study patients, 42.9% were male. Characteristics of the patients are summarized in Table 1. Only 12.4% of the subjects were present smokers, and the prevalence of HTN was 26.4%. The average total cholesterol value was 218 mg/dL. Relatively few of the patients were on medications. The prevalence of stage III, IV and V CKD was 17.4%, 0.2% and 0.2% respectively. There were only 27 patients with ESRD. The overall prevalence of DM was 13.8%. Thirty percent of the diabetic patients and 15.4% of the nondiabetic patients had moderate CKD, ie, a Crcl between 30 and 60 mL/min/1.73 [m.sup.2] (Table 2).

Comparison of Patients with Chronic Kidney Disease and Diabetes Mellitus

Subjects with moderate CKD and without DM were older than subjects with DM and a Crcl of more than 60 mL/min/ 1.73 [m.sup.2] (61.9 versus 52.3 years old) (P < 0.001) (Table 3). The moderate CKD subjects had similar or lower standard cardiac risk factor profiles than the DM subjects with a Crcl [greater than or equal to]60 mL/min/1.73 [m.sup.2]. Total cholesterol levels in patients with moderate CKD and no DM was lower than in patients with DM and a Crcl of more than 60 mL/min/1.73 [m.sup.2] (229 mg/dL versus 235 mg/dL) (P = 0.019). HDL level was higher in subjects with CKD and no DM compared with the patients with DM and a Crcl of more than 60 mL/min/1.73 [m.sup.2] (44 mg/dL versus 41 mg/dL) (P < 0.001). LDL level was similar in the two groups (149 mg/dL versus 151 mg/dL) (P = 0.5). Body mass index in patients with moderate CKD and no DM was 24.9 and it was 30.2 in patients with DM and a Crcl of more than 60 mL/min/1.73 [m.sup.2] (P < 0.001). Fewer people in the CKD and non-DM group had hypertension (38.7%) compared with the group with DM and no CKD (43.0%) but the difference was not statistically significant (P = 0.1).

Comparison of Chronic Kidney Disease and Diabetes Mellitus Patients Accounting for Age

Two hundred eighteen patients in the DM and non-CKD group were older than 55 years of age (Table 4). The mean age of the patients in this subgroup was 61.9 (SD = 4.0) and this was not different from the patients in the CKD and non-DM group who had a mean age of 61.9 (SD = 11) (P = 0.9). Compared with the patients with moderate CKD and no DM, this aged matched subgroup of patients with DM and no CKD still had a higher prevalence of HTN (55.5% versus 38.7%) (P < 0.001), higher BMI (31.2 versus 24.9) (P < 0.001); higher level of total cholesterol (237 mg/dL versus 228 mg/dL) (P = 0.02), higher TG levels (257 mg/dL versus 171 mg/dL) (P < 0.001), and lower level of HDL (41 mg/dL versus 44 mg/dL) (P < 0.001). The LDL level was approximately the same in both groups (151 mg/dL).

ECG-defined Evidence For Ischemia

Based on the Minnesota coding system and Whitehall criteria, 658 (11.1%) of the patients had ECG evidence for possible ischemic heart disease (Table 1). Overall, in patients with DM and without CKD, the prevalence of ECG-defined ischemia was 14.7% compared with 19.7% in patients with moderate CKD and no DM (P = 0.02) (Table 5). In patients with no DM and no CKD, the incidence of possible ECG-defined ischemia was 8%. In patients who had both DM and CKD, the incidence was 26.3%. The prevalence of ECG-defined CHD in a subgroup of patients with DM and no CKD who were age matched with the patients with moderate CKD was 19.3%, similar to the patients with moderate CKD and no DM (19.7%) (P = 0.9).

Because of the lack of specificity associated with ST changes and even left bundle branch block, the analysis was performed based only on the use of pathologic Q waves (Table 5). Q waves were present in 4.8% of the patients with no CKD and no DM. In patients with moderate CKD and no DM compared with the patients with DM and no CKD, the prevalence of pathologic Q waves was similar, overall and age matched (10.8% versus 11.45% and 11.5% versus 11.45%). In patients with CKD and DM, the prevalence of Q waves was 12.9%.

In logistic regression analysis, CKD with an odds ratio of 1.8 (95% CI, 1.4-2.3) was the strongest predictor of Q waves, followed by DM with an odds ratio of 1.61 (95% CI, 1.23-2.12), LDL cholesterol with an odds ratio of 1.50 (95% CI, 1.18-1.91), and HTN with an odds ratio of 1.49 (95% CI, 1.17-1.88) (Table 6). The results were similar in the aged-matched group.

Discussion

TLGS is a screening population. Overall, the subjects had a high prevalence of cardiovascular risk factors and the use of medications was low. The prevalence of elevated blood pressure in the TLGS population was 22%, but only 36% of the hypertensive subjects were receiving blood pressure-lowering agents. Of those treated for hypertension, only 40% had adequately controlled blood pressure. (27) The prevalence of high cholesterol, low HDL, and high TG is 19.3%, 32% and 5.3% respectively in the TLGS population. (28)

Over the past few years the role of CKD in predicting cardiovascular outcomes has been discussed. Investigators have shown that the presence of CKD in association with ischemic cardiac events is associated with poorer outcomes. (29-32)

In our analysis, the incidence of HTN was slightly less in CKD non-DM patients than in DM non-CKD patients. Not surprisingly, markers for metabolic syndrome, low HDL, elevated TG and higher BMI, were more prevalent in the DM population. As expected, the prevalence of ECG evidence of CHD in patients with DM was higher than in the patients without DM. The patients with both DM and impaired kidney function had the highest prevalence of ECG-defined CHD. In the group with moderate CKD and without DM, the prevalence of ECG-defined CHD was 19.7% and significantly higher than in the patients with DM and preserved kidney function. Even in an age-matched group, the prevalence of ECG-defined CHD was similar between patients with moderate CKD and no DM compared with the patients with DM and no CKD. Even using Q waves, with careful attention to HTN, the prevalence was similar (Fig.).

The TLGS data is in agreement with other studies which have shown that moderate CKD is a powerful risk factor for cardiovascular disease even after adjustment for potential con-founders. (33-35) The Bypass Angioplasty Revascularization Investigation (BARI) investigators suggested that in revascularized patients, moderate CKD is a more powerful correlate of cardiovascular death than DM. (34) After 7 years of follow-up in the BARI trial, 85% of 611 patients with DM were free from cardiac death, but just 77% of 46 patients with CKD and no DM were free from cardiac death. Other investigators also showed a higher prevalence of CHD in CKD patients, but significant numbers of patients with CKD in those studies also had DM. (33,36-38) Analysis of the NHANES II database (39) showed that compared with subjects with a Crcl >90 mL/min, crude event rates were greater for those subjects with a baseline Crcl less than 70 mL/min. Participants in the Hypertension Optimal treatment (HOT) trial (40) with an elevated baseline creatinine level, were two to threefold more likely to experience major or fatal cardiovascular events compared with subjects with lower creatinine levels. In contrast to others, (41-44) we used calculated Crcl rather than creatinine level to estimate the kidney function. (44) Serum creatinine alone is not a good marker of kidney function. (45)

Hypertension and hyperlipidemia prevalence are known to be high in patients with CKD. This fact may be an effect of CKD and confers an increased risk of CHD in patients with CKD. (46,47) The higher prevalence of DM among patients with CKD may partly explain the higher prevalence of hyperlipidemia and hypertension in CKD patients. In our study, the prevalence of some cardiovascular risk factors in patients with moderate CKD was actually lower than in patients with DM, probably because we analyzed a group of patients with moderate CKD but no DM. The patients with CKD and no DM were older than the patients with DM and no CKD. We analyzed the data in a subgroup of DM and no CKD patients who were older than 55 and their mean age was statistically matched with the patients with CKD and no DM. Even though the patients with DM and no CKD had a higher incidence of cardiovascular risk factors, their prevalence of ECG-defined ischemic changes was no higher than the group that had CKD and no DM.

We recognize that a limitation of the study is the use of the ECG, particularly since ECG changes associated with LVH may be interpreted as changes consisted with ischemia. However, hypertension had an as high or higher prevalence in the diabetes and no CKD group as it had in the CKD and no DM group. Therefore, the findings are unlikely to be altered by LVH readings. In addition, the findings were not altered when pathologic Q waves were utilized as the sole criteria for ECG ischemic disease. Even in logistic regression analysis, CKD was the strongest predictor of Q waves.

Our study is the first to show that in a screening population, moderate CKD controlled for HTN is as correlated with ECG ischemic criteria as DM.

Conclusion

Our data suggests that moderate CKD alone is as strongly associated with Whitehall-defined ECG ischemic changes as DM. This study adds a large screening population to data from multiple studies that suggest that CKD is either an integrator of CHD risk or a cause of CHD risk. Even in a nonill screening population, moderate CKD may warrant aggressive cardiovascular monitoring and risk factor reduction.

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Arash Rashidi, MD, Arash Ghanbarian, MD, Fereidoun Azizi, MD, and Dale S. Adler, MD

From the Divisions of Nephrology and Cardiology, MetroHealth Medical Center/University Hospitals of Cleveland, Case Western Reserve University, Cleveland, OH; and the Endocrine and Metabolism Research Center, Shaheed Beheshty University of Medical Sciences, Tehran, Iran.

Reprint requests to Arash Rashidi, MD, University Hospitals of Cleveland, Division of Nephrology, Lakeside Bldg Rm 8124-C, 11100 Euclid Ave, Cleveland, Ohio 44106-5048. Email: [e-mail]

Accepted May 31, 2006.

RELATED ARTICLE: Key Points

* Chronic kidney disease is a condition defined by low creatinine clearance.

* Diabetes mellitus is defined by high blood sugar and is a major risk factor for cardiovascular disease.

* Chronic kidney disease is comparable to diabetes as a cardiovascular risk factor.

Table 1. Characteristics of the participants in the Tehran Lipid and
Glucose Study (TLGS)

Characteristic                    All patients

Total number                      5942
Age (year)                          47.6 (SD = 12.5)
Male sex (%)                        42.9
SBP (mm Hg)                        122.2 (SD = 20.1)
DBP (mm Hg)                         79.1 (SD = 10.9)
Body Mass Index                     27.6 (SD = 5.4)
DM (%)                              13.8
Smoking (%)                         12.4
Cerebrovascular accident (a) (%)     1
HTN (b) (%)                         26.4
Laboratory values
  TG (mg/dL)                       185 (SD = 122)
  Total cholesterol (mg/dL)        218 (SD = 46)
  HDL cholesterol (mg/dL)           42 (SD = 11)
  LDL cholesterol (mg/dL)          140 (SD = 39)
  Creatinine (mg/dL)                 1.08 (SD = 0.18)
  Crcl (mL/min/1.73 [m.sup.2])      78.4 (SD = 21)
    CKD stage 1 & 2 (%)             82.2
    CKD stage 3 (%)                 17.38
    CKD stage 4 & 5 (%)              0.4
Medications
  Beta blocker (%)                   9.5
  Calcium channel blocker (%)        2.3
  Diuretic agent (%)                 2.4
  ACEls (%)                          2.5
  ASA (%)                            5
  Antihyperglycemic (%)              5
  Lipid lowering (%)                 2.9
ECG defined ischemia (%)            11.1

(a) According to the past medical history and based on the answer of the
subject to the relevant question.
(b) According to JNC-VII criteria.
SBP, systolic blood pressure; DBP, diastolic blood pressure; DM,
diabetes mellitus; HTN, hypertension; TG, triglycerides; Crcl,
Creatinine clearance; CKD chronic kidney disease; ACEIs, angiotensin-
converting enzyme inhibitor; ASA, acetylsalicylic acid; ECG,
electrocardiogram.

Table 2. Prevalence of CKD in cases with and without DM

                                    Non-DM        DM
                                    (n = 5120)    (n = 822)

Crcl [greater than or equal to] 60  4312 (84.2%)  570 (69.3%)
Stage III                            786 (15.4%)  247 (30%)
Stage IV                              11 (0.2%)     3 (0.4%)
Stage V                               11 (0.2%)     2 (0.2%)

                                    All
                                    (n = 5942)

Crcl [greater than or equal to] 60  4882 (82.1%)
Stage III                           1033 (17.4%)
Stage IV                              14 (0.2%)
Stage V                               13 (0.2%)

CKD, chronic kidney disease; DM, diabetes mellitus; Crcl, Creatinine
clearance.

Table 3. Characteristics of the different subgroups of the participants
in the TLGS

                     Without DM       With DM
Characteristic       30 < Crcl < 60   Crcl [greater than or equal to] 60

Total number         786              570
Age (year)            61.9 (SD = 11)   52.3 (SD = 9)
Male sex (%)          43.4             43.2
SBP (mm Hg)          129 (SD = 23)    132 (SD = 23)
DBP (mm Hg)           78 (SD = 12)     83 (SD = 11)
Body Mass Index       24.9             30.23 (SD = 10.0)
                        (SD = 3.7)
Smoking (%)           10.4             10.5
CVA (a)                2.5              2.3
HTN (b) (%)           38.7             43
Laboratory values
  TG (mg/dL)         171 (SD = 112)   251 (SD = 172)
  Total cholesterol  229 (SD = 47)    235 (SD = 49)
    (mg/dL)
  HDL cholesterol     44 (SD = 12)     41 (SD = 10)
    (mg/dL)
  LDL cholesterol    151 (SD = 41)    149 (SD = 44)
    (mg/dL)
  Creatinine           1.19             1.07 (SD = 0.15)
    (mg/dL)              (SD = 0.20)
  Crcl (mL/min/       50.5             81.2 (SD = 17.3)
    1.73 [m.sup.2])     (SD = 6.7)
Medications
  Beta blocker (%)    17.9             15.3
  Calcium channel      5.5              2.8
    blocker (%)
  Diuretic agent       5.7              3.2
    (%)
  ACEIs (%)            5.3              5.6
  ASA (%)             11.3              8.1
  Antihyperglycemic    0               29.3
    (%)
  Lipid lowering       4.2              9.3
    (%)

Characteristic       P value

Total number
Age (year)           0.000
Male sex (%)         0.934
SBP (mm Hg)          0.02
DBP (mm Hg)          0.000
Body Mass Index      0.000
Smoking (%)          0.26
CVA (a)
HTN (b) (%)          0.111
Laboratory values
  TG (mg/dL)         0.000
  Total cholesterol  0.019
    (mg/dL)
  HDL cholesterol    0.000
    (mg/dL)
  LDL cholesterol    0.485
    (mg/dL)
  Creatinine         0.000
    (mg/dL)
  Crcl (mL/min/      0.000
    1.73 [m.sup.2])
Medications
  Beta blocker (%)
  Calcium channel
    blocker (%)
  Diuretic agent
    (%)
  ACEIs (%)
  ASA (%)
  Antihyperglycemic
    (%)
  Lipid lowering
    (%)

(a) Cerebrovascular accident (%), according to the past medical history
and based on the answer of the subject to the relevant question.
(b) According to JNC-VII criteria.
TLGS, Tehran Lipid and Glucose Study; SBP, systolic blood pressure; DBP,
diastolic blood pressure; DM, diabetes mellitus; Crcl, Creatinine
clearance; CVA, cardiovascular disease; HTN, hypertension; TG,
triglycerides; LDL, low density lipoprotein; HDL, high density
lipoprotein; ACEIs, angiotensinconverting enzyme inhibitor; ASA,
acetylsalicylic acid.

Table 4. Classic cardiac risk factors in the two groups in an
age-matched population

                     Without DM      With DM
Characteristic       30 < Crcl < 60  Crcl [greater than or equal to] 60

Total number         786             218
Age (year)            62              62
Body Mass Index       24.9            31.2
HTN (a) (%)           38.7            55.5
Laboratory values
  TG (mg/dL)         171             257
  Total cholesterol  229             237
    (mg/dL)
  HDL cholesterol     44              41
    (mg/dL)
  LDL cholesterol    151             151
    (mg/dL)

Characteristic       P value

Total number
Age (year)           0.9
Body Mass Index      0.000
HTN (a) (%)          0.000
Laboratory values
  TG (mg/dL)         0.000
  Total cholesterol  0.02
    (mg/dL)
  HDL cholesterol    0.000
    (mg/dL)
  LDL cholesterol    0.9
    (mg/dL)

(a) Based on JNC VII criteria.
DM, diabetes mellitus; Crcl, Creatinine clearance; HTN, hypertension;
TG, triglycerides; HDL, high density lipoprotein; LDL, low density
lipoprotein; CKD, chronic kidney disease; DM, diabetes mellitus.

Table 5. Evidence of coronary heart disease based on Whitehall criteria
and presence of pathologic Q waves on ECG in different groups

                      No CKD and    CKD and  DM and
                      no DM         no DM    no CKD          DM and CKD

ECG-defined ischemia  8% (345) (a)  19.7%    14.7% (84)      26.3% (65)
  based on Whitehall                  (155)  19.3% (b,c)
  criteria                                     (42)
Pathologic Q waves    4.8% (209)    11.45%   10.8% (d) (62)  12.9% (32)
                                      (90)   11.5% (b) (25)

(a) Number in parentheses represents number of cases.
(b) Age matched sub group with no-DM and CKD group.
(c) P = 0.881 in comparison of non-diabetics with CKD.
(d) P = 0.741 in comparison of non-diabetics with CKD.
ECG, electrocardiogram; DM, diabetes mellitus; CKD, chronic kidney
disease.

Table 6. Comparing the other major risk factors, CKD is the strongest
predictor of Q waves in ECG. The odds ratio for CKD is even more than
the odds ratio for DM (a)

         Odds ratio  95% confidence interval  P value

LDL      1.50        1.18-1.91                0.001
HDL      0.88        0.70-1.12                0.293
TG       1.19        0.94-1.5                 0.153
CKD      1.80        1.41-2.31                0.000
HTN      1.49        1.17-1.88                0.001
DM       1.61        1.23-2.12                0.001
Smoking  1.14        0.79-1.64                0.48
Sex      1.136       0.89-1.45                0.304

(a) Results were similar in age match group.
CKD, chronic kidney disease; ECG, electrocardiogram; DM, diabetes
mellitus; LDL, low density lipoprotein; HDL, high density lipoprotein;
TG, triglycerides; HTN, hypertension; DM, diabetes mellitus; HTN,
hypertension; DM, diabetes mellitus.

         No DM &  CKD & No  DM & No
         No CKD   DM        CKD      CKD & DM

Q waves   4.80%   11.45%    10.80%   12.90%
HTN      20%      38.70%    43%      57.10%

HTN -- hypertension; DM -- diabetes mellitus

Fig. Chronic kidney disease controlled for hypertension is as frequently
associated with Q waves as is diabetes.