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Are CSN and NKF-K/DOQI mineral metabolism guidelines for hemodialysis patients achievable? results from a provincial renal program.

Learning objectives

After reading the article, the reader will be able to:

1. Understand the differences in recommendations between the Canadian Society of Nephrology (CSN) and National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) mineral metabolism guidelines.

2. Recognize the most common mineral metabolism disturbances observed in dialysis patients.

3. Review the prevalence of prescribed medications for disorders of mineral metabolism.

4. Discuss the limitations of a cross-sectional study design.

Introduction

Disturbances in mineral metabolism have been associated with morbidity, decreased quality of life, and cardiovascular mortality in patients receiving hemodialysis (Block, Hulbert-Shearon, Levin, & Port, 1998; Block et al., 2004; Ganesh, Stack, Levin, Hulbert-Shearon, & Port, 2001; Noordzij et al., 2005; Slinin, Foley, & Collins, 2005; Stevens, Djurdjev, Cardew, Cameron, & Levin, 2004; Young et al., 2005). The Canadian Society of Nephrology (CSN) recently published a guideline on mineral metabolism for patients receiving hemodialysis (Jindal et al., 2006). The calcium, phosphorus, and parathyroid hormone targets recommended by the CSN encompass a wider range of values as compared to the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) guidelines (see Table One) (National Kidney Foundation, 2003). Previous studies have found that a large proportion of patients on hemodialysis have mineral metabolism parameters that do not fall within the NKF-K/DOQI targets (Wald, Tentori, Tighiouart, Zager, & Miskulin, 2007; Wei et al., 2006; Young et al., 2004). However, to date, no published data are available on the ability to meet the less stringent CSN targets. In addition, little published information is available regarding the medications used in an attempt to achieve either the CSN or NKF-K/DOQI mineral metabolism targets.
Table One. National Kidney Foundation Kidney Disease Outcomes Quality
Initiative versus Canadian Society of Nephrology targets for bone and
mineral metabolism

Measurement CSN NKF-K/DOQI

Ca (mmol/L) 2.1-2.6 2.1-2.37 (specifies CCa)
PCM (mmol/L) 0.8-1.78 1.13-1.78
PTH (pmol/L 10.6-53.0 16.5-33.0

Notes:

CSN=Canadian Society of Nephrology

NKF-K/DOQI=National Kidney Foundation Kidney Disease Outcomes Quality
Initiative

Ca=serum calcium

CCa=corrected serum calcium

PO4=serum phosphate

PTH=serum intact parathyroid hormone


The Manitoba Renal Program (MRP) is responsible for all adult patients requiring chronic kidney disease care for the entire province. The MRP consists of hemodialysis, peritoneal dialysis and renal health clinics at three centres in Winnipeg, one in Brandon, and 13 satellite hemodialysis units throughout the province. There are approximately 800 hemodialysis, 180 peritoneal dialysis, and 3,600 renal health clinic patients in the program currently.

The present evaluation examined the levels of albumin-corrected serum calcium (CCa), serum phosphorus (PO4), and intact parathyroid hormone (PTH) in all hemodialysis patients in our provincial renal program in June 2005 to determine what proportion of these patients had laboratory values within the range of the CSN and NKF-K/DOQI guidelines. We also collected data on the use of phosphate binders, vitamin D, and cinacalcet.

Methods

All patients receiving chronic maintenance hemodialysis for at least three months in the MRP in June 2005 were included in the evaluation. Patients were excluded if they did not have all four laboratory values (serum calcium, albumin, PO4, and PTH) available. Values of serum calcium, albumin, PO4, and PTH were collected from the routine mid-month blood work in all patients. Albumin-corrected calcium was calculated using the Payne formula (adjusted calcium = total serum calcium + [0.02 (40 albumin)] where calcium is in mmol/L and albumin in g/L) (Payne, Little, Williams, & Milner, 1973, p.645). As the CSN guidelines specify that serum calcium levels should be maintained within the normal range (Jindal et al., 2006), the normal range for our centre (2.1 mmol/L to 2.6 mmol/L) was chosen as the target serum calcium. The standard dialysate calcium concentration in our program was 1.5 mmol/L, but data on individual patient's calcium baths were not captured. Serum samples were analyzed at the local hospitals' laboratories. Serum calcium, albumin, and PO4 were determined using standard assays. Serum PTH concentrations were determined using the intact PTH assay, Roche Diagnostics Canada, Laval, Quebec. The clinicians taking care of the patients managed the parameters of bone and mineral metabolism according to standard practice that was consistent with the NKF-K/DOQI guidelines (data were collected prior to the release of the CSN guidelines) without the use of program-specific algorithms or collaborative prescribing agreements among health professions. Patients requiring vitamin D compounds received oral or intravenous calcitriol and those requiring phosphate binders received calcium carbonate, sevelamer, aluminum hydroxide, or a combination of these agents. Cinacalcet was available for use in up to 20 patients through a compassionate release program that required patients to meet the following criteria: PTH > 53 pmol/L and/or total calcium > 2.60 mmol/L; and/or PO4 > 1.78 mmol/L; and/or refractory to or with contraindications to vitamin D. All data were obtained from the hemodialysis charts, and were entered into a database (Microsoft Access[R]) by a nurse, a pharmacy technician, and a dietitian depending on the program site.

Results

Of 748 patients receiving chronic maintenance hemodialysis in the MRP that were evaluated, 138 did not have a PTH value and 64 did not have an albumin value available in June 2005 and were not included in the evaluation. The remaining 546 patients who had all four laboratory values available were included in the analysis. The demographic characteristics of the population are detailed in Table Two. Table Three illustrates the results by NKF-K/DOQI and CSN target ranges. The most glaring mineral metabolism abnormalities observed were high phosphorus (45% of patients) and low parathyroid hormone (31% to 45% depending on target used) concentrations.
Table Two. Demographic characteristics

Parameter Mean [+ or -] SD values

Hemodialysis patients, number 546
Age, years (mean[+ or -]SD) 60[+ or -]15
Male sex 268 (49%)

Ethnic Origins

 Caucasian 264 (48.4%)
 Aboriginal (a) 226 (41.4%)
 Asian (b) 50 (9.2%)
 Black 5 (0.9%)
 Other 1 (0.2%)
Duration of dialysis, years (mean[+ or -]SD) 6.82[+ or -]5.24
Reasons for dialysis (%)
 Diabetes mellitus 274 (50.2%)
 Glomerulonephritis 101 (18.5%)
 Other 106 (19.5%)
 Unknown 28 (5.1%)
 Reno vascular disease 16 (2.9%)
 Hypertension 21 (3.8%)

(a) Includes Inuit, Metis, North American Indian
(b) Includes Filipino, Oriental, and East Indian


Medication use by the CSN CCa, PO4, and PTH targets is outlined in Tables Four A, Four B, and Four C respectively. Overall, 85.5% of patients were prescribed calcium carbonate, 16.1% were prescribed sevelamer, and 1.3% were prescribed aluminum as a phosphate binder. This is consistent with Canadian DOPPS II (2002-2004) data, which indicate that 81.5% of Canadian patients were prescribed a calcium-based binder and 14.2% were prescribed sevelamer (personal communication, Dr. David Mendelssohn, Oct. 17, 2007). A total of 30.2% of MRP patients were prescribed calcitriol (17.4% oral, 12.8% intravenous) and 2.7% were prescribed cinacalcet. Almost one-quarter of hyperphosphatemic patients were taking sevelamer at an average dose of eight tablets (6400 mg) daily in combination with calcium containing binders at an average dose of 2.5 grams elemental calcium per day and were still not able to lower their phosphorus below the CSN and NKF-K/DOQI target of 1.78 mmol/L (see Table Four B). In addition, despite using high doses of calcium containing phosphate binders (range 1.9-2.9 grams elemental calcium per day, Table Four A), only 10% of our patient population was found to be hypercalcemic according to CSN targets. The CSN Mineral Metabolism Guideline, unlike NKF-K/DOQI, does not limit the daily oral calcium intake and instead recommends that serum calcium levels be maintained within the normal range (Jindal et al., 2006), which our results appear to support.
Table Four A. Use of phosphate binders by CSN corrected calcium targets

CCa (mmol/L) n Calcium n; Sevelamer n; Al. hydroxide
 % patients; % patients, n; % patients;
 grams elemental no. 800 mg grams/day
 Ca/day tablets/day

<2.1 49 46, 94%, 2.9 1, 2%, 9 2, 4%, 1.5
2.1-2.6 440 377, 86%, 2.1 70, 16%, 8 5, 1%, 3.7
>2.6 57 44, 77%, 1.9 16, 28%, 7 0

Notes:
Some patients were receiving more than one phosphate binder.
CSN=Canadian Society of Nephrology
CCa=corrected serum calcium

Table Four B. Use of phosphate binders by CSN PO4 targets

PO4 (mmol/L) n Calcium n; Sevelamer n; Al hydroxide
 % patients; % patients, n; % patients;
 grams no. 800 mg grams/day
 elemental tablets/day
 Ca/day

<0.8 15 11, 73%, 1.9 0 0
0.80 [degrees] 1.78 288 250, 87%, 1.9 29, 10%, 7.3 2, 0.7%, 2.9
> 1.78 243 214, 88%, 2.5 59, 24%, 8.2 5, 2%, 3.4

Notes:
Some patients were receiving more than one phosphate binder.
CSN=Canadian Society of Nephrology
PO4=serum phosphate

Table Four C. Use of calcitriol and cinacalcet by CSN PTH targets

PTH n Oral calcitriol IV calcitriol Cinacalcet n, %,
(pmol/L) n, %, mcg/week n, %, meg/week mg/day

< 10.6 168 21, 12.5%, 2.79 4, 2.4%, 3.25 0
10.6-53 310 64, 20.6%, 4.92 30, 9.7%, 3.08 1, 0.3%, 30
>53 68 11, 16.2%, 1.41 39, 57.3%, 3.73 14, 20.6%, 40.7

Notes:
Some patients were on both calcitriol and cinacalcet.
CSN=Canadian Society of Nephrology
PTH=serum intact parathyroid hormone


Discussion

In a cross-sectional evaluation of hemodialysis patients in a provincial renal program, we observed that only 81%, 53% and 57% of patients met CSN targets for calcium, phosphate and PTH respectively. A greater proportion of patients was able to achieve all three of the more lenient CSN mineral metabolism targets (26%) versus NKF-K/DOQI (6%). However, the vast majority of hemodialysis patients are still not meeting either the CSN or NKF-K/DOQI targets. Our low proportion of patients meeting all three of the NKF-K/DOQI targets simultaneously (see Table Three, 6%) is very similar to what others have reported using data from longer periods of time (three months to two years) with ranges of 5.3% (Wei et al., 2006) to 5.5% (Young et al., 2004). The outlook becomes even more dismal when mineral metabolism parameters are examined over longer time periods. One group of investigators has shown that only 2.4% of patients were able to maintain consistent control of all NKF-K/DOQI mineral metabolism targets over a 12-month period (Wald et al., 2007). To our knowledge, there are not any previous publications that have examined achievement of the CSN targets.
Table Three. Proportion of patients below, within, and above the
guideline ranges

Measurement CSN MRP K/DOQI MRP
 (n=546) (n=546)

CCa (mmol/L) < 2.1 49 (9%) < 2.1 49 (9%)

 2.1-2.6 440 (81%) 2.1-2.37 217 (40%)

 > 2.6 57 (10%) > 2.37 280 (51%)

PO4 (mmol/L) < 0.8 15 (3%) < 1.13 73 (13%)

 0.8-1.78 288 (53%) 1.13-1.78 230 (42%)

 > 1.78 243 (45%) > 1.78 243 (45%)

PTH (pmol/L) < 10.6 168 (31%) < 16.5 245 (45%)

 10.6-53 310 (57%) 16.5-33 153 (28%)

 > 53 68 (12%) > 33 148 (27%)

Meeting all three CSN Targets 142 (26%) K/DOQI Targets 33 (6%)
targets

Notes:
CSN=Canadian Society of Nephrology

NKF-K/DOQI=National Kidney Foundation Kidney Disease Outcomes Quality
Initiative

CCa=corrected serum calcium

PO4=serum phosphate

PTH=serum intact parathyroid hormone


The CSN Mineral Metabolism Guidelines recommend to "give priority to phosphate and calcium targets over the management of PTH" (Jindal et al., 2006, p. S12). In our provincial data, more than 80% of patients were able to achieve the CSN calcium target range while only 53% were able to achieve the CSN phosphate target range. The vast majority of patients outside the CSN phosphate target were due to hyperphosphatemia (see Table Three). DOPPS II (2002-2004 data) mentions that 85% of patients within the NKF-K/DOQI target range were prescribed any type of phosphate binder (Young et al., 2005). In contrast, 99% of our provincial renal program patients who were within the NKF-K/DOQI PO4 targets and 91% who were within the CSN PO4 targets were prescribed a phosphate binder. Even more revealing is that 88% of patients in DOPPS II (Young et al., 2005) and 96% of patients in our provincial program who were hyperphosphatemic were prescribed phosphate binders. This very high usage of phosphate binders in patients who are still not able to achieve the phosphorus targets may indicate that the phosphate binding agents available at that time were inadequate treatments (Wald et al., 2007; Wei et al., 2006; Young et al., 2005). However, caution should be used in interpreting these data, as this may also represent medication non-adherence.

DOPPS II data reported that 48% of patients (Young et al., 2004) had an intact PTH concentration below 16.5 pmol/L; similarly, we observed 45%. This suggests that hypoparathyroidism and subsequent development of adynamic bone disease, and not hyperparathyroidism, should be the predominant concern in this era of mineral metabolism. Low PTH concentrations have been associated with increased morbidity and mortality (Avram, Mittman, Myint, & Fein, 2001; Guh et al., 2002). The main cause of hypoparathyroidism in one study of hemodialysis patients was parathyroidectomy (77% of patients). However, patients with a parathyroidectomy had better survival despite their low PTH values (Dussol et al., 2007). Another recent study reported that parathyroidectomy is associated with a lower risk of fractures (Rudser, de Boer, Dooley, Young, & Kestenbaum, 2007). These data may indicate that the benefits of surgical amelioration of secondary hyperparathyroidism outweigh the risk of hypoparathyroidism and development of adynamic bone disease. Another factor that may have influenced our low PTH results is the large numbers of patients with diabetes. Patients with diabetes as the cause of their kidney disease represented more than 50% of our hemodialysis population (see Table Two) and it has been shown that hyperglycemia and insulin deficiency inhibit PTH secretion (Haris et al., 2006). However, examining our use of PTH-lowering agents (see Table Four C), one disconcerting value is that approximately 15% of patients with a PTH < 10.6 pmol/L were still receiving calcitriol. The CSN guidelines specifically state that vitamin D sterols should be discontinued when PTH levels decrease below target levels. Simply discontinuing the vitamin D sterol in these patients would certainly be the simplest "treatment" to help to increase their PTH.

Limitations

This evaluation has several limitations. First, due to the cross-sectional design, all four laboratory values were not available for all patients receiving hemodialysis in Manitoba in June 2005. Although calcium and phosphate are part of routine monthly blood work at all MRP hemodialysis sites, PTH is normally measured every three months and albumin is not always ordered.

Second, the dialysis dose and frequency, which may have had a bearing on the phosphate concentrations, were not collected as part of this evaluation. The majority of MRP patients received conventional hemodialysis three times per week. However, some patients are dialyzed twice weekly. The MRP did not have any daily or nocturnal hemodialysis patients.

Third, we did not examine the effect of a patient missing or shortening hemodialysis sessions on mineral metabolism targets. A recent study has demonstrated that each 1% increase in the frequency of missed hemodialysis sessions was associated with a decrease in consistent control of calcium, phosphate, and Ca x P product of 2%, 4%, and 1% respectively (Wald et al., 2007). It also is known that 19% of the total phosphate removal occurs in the last hour of a four-hour treatment (Gutzwiller et al., 2002), so patients missing even one hour of dialysis time may need to ingest significantly more phosphate binders to achieve the same phosphate removal (Sherman, 2005).

Fourth, control of phosphorus through diet and phosphate binders requires a great deal of patient education and adherence to the prescribed medications. Non-adherence with phosphate binders has been self-reported by 38% of dialysis patients (Tomasello, Dhupar & Sherman, 2004). One study demonstrated that a one-to-one teaching session by a renal dietitian on PO4 management produced a statistically significant reduction in serum PO4 values that persisted for at least three months (Ashurst & Dobbie, 2003). However, another study reported that the patient to dietitian ratio had no discernible association with mineral metabolism control (Wald et al., 2007). We did not examine the data for variations in patient-dietitian or patient-pharmacist ratios to determine if this would influence the proportion of patients achieving control. However, our provincial renal program does employ both renal dietitians and renal pharmacists in all the hemodialysis units. We also did not examine medication adherence in this evaluation.

Fifth, at the time of our evaluation, we did have access to cinacalcet through a compassionate release program. However, the data in this evaluation were collected in the first few months of patient enrolment and, hence, we were not able to demonstrate a significant impact of cinacalcet on PTH (see Table Four C). However, other investigators have reported that use of cinacalcet does aid in the achievement of NKF-K/DOQI targets (Moe et al., 2005).

Finally, we did not record the calcium concentration of individual patients' dialysis bath. However, the standard dialysate calcium concentration in our program in June 2005 was 1.5 mmol/L. Studies have shown that using a low-calcium dialysate (1.25 mmol/L) in hemodialysis patients with PTH below 16.5 pmol/L leads to significant and sustained increases in PTH and alkaline phosphatase (Lezaic et al., 2007; Spasovski et al., 2007). It is important to note that these studies were performed in patients who were also receiving calcium-containing phosphate binders. Another recent study indicated that switching from calcium carbonate to sevelamer in patients with PTH < 6.4 pmol/L significantly decreased the serum levels of calcium, resulting in the elevation of PTH concentrations from 3.3 pmol/L to 10.0 pmol/L at 48 weeks (Iwata et al., 2007). The dialysate calcium concentration employed in this study was 1.5 mmol/L. A limitation of the aforementioned studies is that they did not examine the effects of the treatment on bone histomorphometry using bone biopsies. One study that did examine patients with biopsy-proven adynamic bone disease, found that successful renal transplantation led to either partial or complete recovery of bone turnover (Abdallah et al., 2006).

Implications for practice

These results were disseminated to all MRP nephrologists, pharmacists, charge nurses, and dietitians at a symposium held in October 2005. The purpose of the symposium was to develop a consistent approach in the MRP in the management of disorders of mineral metabolism. Some of the recommendations that were approved included: 1. Standard dialysate calcium will be 1.2 mmol/L; 2. Serum calcium will be reported by all labs as total and albumin-corrected calcium; 3. Ionized calcium will no longer be measured routinely; 4. Target albumincorrected calcium will be < 2.6 mmol/L; 5. Target serum phosphorus level will be [less than or equal to] 1.8 and initial treatment of high phosphorus must include dietary instruction and review, and optimal dialysis (if on dialysis) before binder therapy.

We are also in the process of developing a mineral metabolism database in which laboratory values and medications will be entered on a quarterly basis for all patients in the MRP. Ongoing evaluation using this database will focus on improving the number of patients achieving calcium, phosphate and PTH targets over time, particularly those with hyperphosphatemia and hypoparathyroidism.

Recommendations for future research

The impact of the use of agents such as lanthanum carbonate, calcium acetate, sevelamer, or cinacalcet on bone metabolism parameters outside the setting of a randomized controlled trial should be evaluated in a prospective manner. In addition, prospective randomized trials are needed to demonstrate that achievement of the CSN or NKF-K/DOQI guidelines do, in fact, decrease mortality in patients receiving hemodialysis.

Conclusion

Only a small proportion of patients was able to achieve all three CSN or NKF-K/DOQI mineral metabolism targets simultaneously. The majority of our patients falling outside of the target ranges presented with either hyperphosphatemia or hypoparathyroidism. These findings highlight the difficulties we still face in the management of mineral metabolism in hemodialysis patients.

References

Abdallah, K.A., Jorgetti, V., Pereira, R.C., Reis, L.M., Pereira, L.M., Correa, P.H. et al. (2006). Improvement of adynamic bone disease after renal transplantation. Brazilian Journal of Medical and Biological Research, 39, 31-41.

Ashurst, I.B., & Dobbie, H. (2003). A randomized controlled trial of an educational intervention to improve phosphate levels in hemodialysis patients. Journal of Renal Nutrition 13, 267-274.

Avram, M.M., Mittman, N., Myint, M.M., & Fein, P. (2001). Importance of low serum intact parathyroid hormone as a predictor of mortality in hemodialysis and peritoneal dialysis patients: 14 years of prospective observation. American Journal of Kidney Diseases, 38, 1351-1357.

Block, G.A., Hulbert-Shearon, T.E., Levin, N.W., & Port, F.K. (1998). Association of serum phosphorus and calcium x phosphate product with mortality risk in chronic hemodialysis patients: A national study. American Journal of Kidney Diseases, 31, 607-617.

Block, G.A., Klassen, P.S., Lazarus, J.M., Ofsthun, N., Lowrie, E.G., & Chertow, G.M. (2004). Mineral metabolism, mortality, and morbidity in maintenance hemodialysis. Journal of the American Society of Nephrology, 15, 2208-2218.

Dussol, B., Morand, P., Martinat, C., Lombard, E., Portugal, H., Brunet, P., et al. (2007). Influence of parathyroidectomy on mortality in hemodialysis patients: A prospective observational study. Renal Failure, 29, 579-586.

Ganesh, S.K., Stack, A.G., Levin, N.W., Hulbert-Shearon, T., & Port, F.K. (2001). Association of elevated serum PO(4), Ca x PO(4) product, and parathyroid hormone with cardiac mortality risk in chronic hemodialysis patients. Journal of the American Society of Nephrology, 12, 2131-2138.

Guh, J.Y., Chen, H.C., Chuang, H.Y., Huang, S.C., Chien, L.C., & Lai, Y.H. (2002). Risk factors and risk for mortality of mild hypoparathyroidism in hemodialysis patients. American Journal of Kidney Diseases, 39, 1245-1254.

Gutzwiller, J.P., Schneditz, D., Huber, A.R., Schindler, C., Gutzwiller, F., & Zehnder, C.E. (2002). Estimating phosphate removal in haemodialysis: an additional tool to quantify dialysis dose. Nephrology Dialysis Transplantation, 17, 1037-1044.

Haris, A., Sherrard, D.J., & Hercz, G. (2006). Reversal of adynamic bone disease by lowering dialysate calcium. Kidney International, 70, 931-937.

Iwata, Y., Wada, T., Yokoyama, H., Toyama, T., Kitajima, S., Okumura, T., et al. (2007). Effect of sevelamer hydrochloride on markers of bone turnover in Japanese dialysis patients with low biointact PTH levels. Internal Medicine 46, 447-452.

Jindal, k., chan, c. T., deziel, c., hirsch, d., soroka, s. D., tonelli, m., et al. (2006). Hemodialysis clinical practice guidelines for the canadian society of nephrology. Journal of the american society of nephrology, 17, s1-27.

Lezaic, V., Pejanovic, S., Kostic, S., Pljesa, S., Dimkovic, N., Komadina, L., et al. (2007). Effects of lowering dialysate calcium concentration on mineral metabolism and parathyroid hormone secretion: A multicentric study. Therapeutic Apheresis and Dialysis, 11, 121-130.

Moe, S.M., Chertow, G.M., Coburn, J.W., Quarles, L.D., Goodman, W.G., Block, G.A., et al. (2005). Achieving NKF-K/DOQI bone metabolism and disease treatment goals with cinacalcet HCl. Kidney International, 67, 760-771.

National Kidney Foundation (2003). K/DOQI clinical practice guidelines for bone metabolism and disease in chronic kidney disease. American Journal of Kidney Diseases, 42, S1-201.

Noordzij, M., Korevaar, J.C., Boeschoten, E.W., Dekker, F.W., Bos, W.J., & Krediet, R.T. (2005). The Kidney Disease Outcomes Quality Initiative (K/DOQI) Guideline for Bone Metabolism and Disease in CKD: Association with mortality in dialysis patients. American Journal of Kidney Diseases, 46, 925-932.

Payne, R.B., Little, A.J., Williams, R.B., & Milner, J.R. (1973). Interpretation of serum calcium in patients with abnormal serum proteins. British Medical Journal, 4, 643-646.

Rudser, K.D., de Boer, I.H., Dooley, A., Young, B., & Kestenbaum, B. (2007). Fracture risk after parathyroidectomy among chronic hemodialysis patients. Journal of the American Society of Nephrology, 18, 2401-2407.

Sherman, R.A. (2005). Pill burden, compliance and hyperphosphatemia in dialysis patients. Retrieved February 16, 2008, from http://www.medscape.com/viewarticle/498979

Slinin, Y., Foley, R.N., & Collins, A.J. (2005). Calcium, phosphorus, parathyroid hormone, and cardiovascular disease in hemodialysis patients: the USRDS waves 1, 3, and 4 study. Journal of the American Society of Nephrology, 16, 1788-1793.

Spasovski, G., Gelev, S., Masin-Spasovska, J., Selim, G., Sikole, A., & Vanholder, R. (2007). Improvement of bone and mineral parameters related to adynamic bone disease by diminishing dialysate calcium. Bone, 41, 698-703.

Stevens, L.A., Djurdjev, O., Cardew, S., Cameron, E.C., & Levin, A. (2004). Calcium, phosphate, and parathyroid hormone levels in combination and as a function of dialysis duration predict mortality: Evidence for the complexity of the association between mineral metabolism and outcomes. Journal of the American Society of Nephrology, 15, 770-779.

Tomasello, S., Dhupar, S., & Sherman, R.A. (2004). Phosphate binders, K/DOQI guidelines, and compliance: the unfortunate reality. Dialysis and Transplantation, 33, 236-242.

Wald, R., Tentori, F., Tighiouart, H., Zager, P.G., & Miskulin, D.C. (2007). Impact of the Kidney Disease Outcomes Quality Initiative (KDOQI) Clinical Practice Guidelines for Bone Metabolism and Disease in a large dialysis network. American Journal of Kidney Diseases, 49, 257-266.

Wei, M., Taskapan, H., Esbaei, K., Jassal, S.V., Bargman, J.M., & Oreopoulos, D.G. (2006). K/DOQI guideline requirements for calcium, phosphate, calcium phosphate product, and parathyroid hormone control in dialysis patients: Can we achieve them? International Urology and Nephrology, 38, 739-743.

Young, E.W., Akiba, T., Albert, J.M., McCarthy, J.T., Kerr, P.G., Mendelssohn, D.C., et al. (2004). Magnitude and impact of abnormal mineral metabolism in hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS). American Journal of Kidney Diseases, 44, 34-38.

Young, E.W., Albert, J.M., Satayathum, S., Goodkin, D.A., Pisoni, R.L., Akiba, T., et al. (2005). Predictors and consequences of altered mineral metabolism: The Dialysis Outcomes and Practice Patterns Study. Kidney International, 67, 1179-1187.

Case One

Ms. A.L. is a 60-year-old female on chronic hemodialysis three times weekly for the past six months. Her mid-month blood work comes back with the following: Ca 2.1 mmol/L; PO4 2.2 mmol/L; and PTH 8.3 pmol/L.

Questions 1 to 4 refer to this case.

1. Which of the Canadian Society of Nephrology (CSN) 2006 mineral metabolism targets is Ms. A.L. out of range for?

(a) Ca

(b) PO4

(c) PTH

(d) both PO4 and PTH

2. Ms. A.L.'s medications consist of calcium carbonate 625 mg (250 mg elemental Ca/tab) one tablet PO TID with meals and calcitriol 0.25 mcg PO on Mondays, Wednesdays, and Fridays. Based on her mid-month blood work, which of the following is the most appropriate adjustment to her medications?

(a) increase calcium carbonate and continue same dose of calcitriol

(b) decrease calcium carbonate and increase calcitriol

(c) increase calcium carbonate and discontinue calcitriol

(d) discontinue calcium carbonate and calcitriol and change to sevelamer

3. Ms. A.L.'s phosphate concentration may also have resulted from which of the following?

(a) taking her calcium carbonate as instructed

(b) shortening her dialysis sessions

(c) following a low phosphate diet

(d) attending all her scheduled hemodialysis sessions

4. Ms. A.L. asks you, "What number should my phosphate be?" What is the highest target PO4 concentration according to the Canadian Society of Nephrology (CSN) 2006 and National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) 2003 guidelines?

(a) 1.45

(b) 1.78

(c) 2

(d) 2.2

End of case one

5. The most common mineral metabolism abnormalities observed in the hemodialysis population in the Manitoba Renal Program study were:

(a) hyperphosphatemia and hyperparathyroidism

(b) hypophosphatemia and hypoparathyroidism

(c) hyperphosphatemia and hypoparathyroidism

(d) hyperphosphatemia and hypocalcemia

6. The per cent of hemodialysis patients in the Manitoba Renal Program who met all three CSN (2006) mineral metabolism targets was:

(a) 6%

(b) 12%

(c) 26%

(d) 45%

7. In this study, what percentage of hemodialysis patients who were within the CSN (2006) phosphate target (0.80-1.78 mmol/L) were prescribed calcium containing phosphate binders?

(a) 7.3%

(b) 8.2%

(c) 73%

(d) 87%

8. The majority of Canadian dialysis patients (according to the Dialysis Outcomes and Practice Patterns Study - DOPPS II data) are prescribed which of the following phosphate binders?

(a) calcium-based

(b) sevelamer

(c) lanthanum

(d) aluminum-based

9. Which of the following targets should be given priority according to the Canadian Society of Nephrology (2006) mineral metabolism guidelines?

(a) calcium

(b) phosphate

(c) calcium and phosphate

(d) phosphate and parathyroid hormone

10. Which of the following medications has been shown to increase parathyroid hormone (PTH) levels in patients with hypoparathyroidism?

(a) calcium carbonate

(b) sevelamer

(c) calcitriol

(d) cinacalcet

Post-test instructions:

* Select the best answer and circle the appropriate letter on the answer grid below.

* Complete the evaluation.

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Post-test answer grid

Please circle your answer choice:

1. a b c d
2. a b c d
3. a b c d
4. a b c d
5. a b c d
6. a b c d
7. a b c d
8. a b c d
9. a b c d
10. a b c d
Evaluation

 Strongly disagree Strongly agree

1. The offering met the stated 1 2 3 4 5
 objectives.

2. The content was related to the 1 2 3 4 5
 objectives.

3. This study format was effective 1 2 3 4 5
 for the content.

4. Minutes required to read and
 complete:

 50 75 100 125 150


By Lori D.Wazny, PharmD, Colette B. Raymond, PharmD, MSc, Esther M. Lesperance, RT, and Keevin N. Bernstein, MD, FRCPC

Lori D. Wazny, PharmD, Clinical Pharmacist, Manitoba Renal Program.

Colette B. Raymond, PharmD, MSc, Clinical Pharmacist, Manitoba Renal Program.

Esther M. Lesperance, RT, Application Administrator, Manitoba Renal Program

Keevin N. Bernstein, MD, FRCPC, Professor, Faculty of Medicine, University of Manitoba

Address correspondence to: Lori Wazny, PharmD, Dept. of Pharmaceutical Services, Health Sciences Centre, 820 Sherbrook St., Winnipeg, MB R3A 1R9 E-mail: Lwazny@hsc.mb.ca

Submitted for publication: August 24, 2007.

Accepted for publication in revised form: March 8, 2008.
COPYRIGHT 2008 Canadian Association of Nephrology Nurses & Technologists
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2008 Gale, Cengage Learning. All rights reserved.

Article Details
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Title Annotation:CONTINUING EDUCATION SERIES; Canadian Society of Nephrology; National Kidney Foundation's Kidney Disease Outcomes Quality Initiative
Author:Wazny, Lori D.; Raymond, Colette B.; Lesperance, Esther M.; Bernstein, Keevin N.
Publication:CANNT Journal
Geographic Code:1CANA
Date:Apr 1, 2008
Words:5137
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