Management

Given the high prevalence of vitamin D deficiency in CKD and dialysis patients, limiting screening and treatment of vitamin D deficiency to only those with hyperparathyroidism is not appropriate. Additionally, screening for vitamin D deficiency in CKD and dialysis patients by measuring 25(OH)D levels is expensive and is probably unnecessary as treatment can be provided safely to virtually all patients.8,9 The very high prevalence of vitamin D deficiency in both CKD and dialysis populations means most patients will require supplementation.

 

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Typical supplemental doses of vitamin D can replete vitamin D deficient patients while presenting no risk to patients with adequate vitamin D stores. Using just such a global treatment strategy in our dialysis center, our group has found a single monthly 50,000 IU ergocalciferol capsule repleted virtually all vitamin D deficient patients within six months and resulted in no dangerously high vitamin D levels.8 After two years of continued monthly supplementation, 25(OH)D levels remain in a safe and satisfactory range without apparent adverse effects.

 

 

Hyperparathyroidism is a clear indication for use of VDRAs in CKD and dialysis patients, and provides the opportunity for clinicians to treat calcitriol deficiency. Serum calcium and phosphorus should be monitored, and the VDRA dose adjusted or VDRAs with wider therapeutic windows used to avoid hypercalcemia and minimize increases in serum phosphorus. Hypocalcemia is another opportunity to use VDRAs.

 

Claims that VDRA-induced changes in calcium and phosphorus increase mortality are speculative at best, and inconsistent with available observational data. These claims also have at their core the belief that a deficiency in the calcitriol hormone is good for patients. Although use of VDRAs when hyperparathyroidism is not present appears to provide a survival benefit in observational studies, randomized controlled trials in CKD and dialysis patients with low or normal PTH are needed to confirm that such therapy provides benefits that outweigh potential harm.

 

References

  1. Levin A, Bakris GL, Molitch M, et al. Prevalence of abnormal serum vitamin D, PTH, calcium, and phosphorus in patients with chronic kidney disease: results of the study to evaluate early kidney disease. Kidney Int. 2007;71(1):31-38.
  2. Wolfe M, Shah A, Gutierrez O, et al. Vitamin D levels and early mortality among incident hemodialysis patients. Kidney Int. 2007;Advance online publication, 8 August 2007; doi:10.1038/sj.ki.5002451.
  3. Wu-Wong JR. The potential for vitamin D receptor activation in cardiovascular research. Expert Opin Investig Drugs. 2007;16:407-411.
  4. Wu-Wong JR. Vitamin D receptor: a highly versatile nuclear receptor. Kidney Int. 2007;72(3):237-239.
  5. Chonchol M, Scragg R. 25-Hydroxyvitamin D, insulin resistance, and kidney function in the Third National Health and Nutrition Examination Survey. Kidney Int. 2007;71:134-139.
  6. Martins D, Wolf M, Pan D, et al. Prevalence of cardiovascular risk factors and the serum levels of 25-hydroxyvitamin D in the United States: data from the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2007;167:1159-1165.
  7. Forman JP, Giovannucci E, Holmes MD, et al. Plasma 25-hydroxyvitamin D levels and risk of incident hypertension. Hypertension. 2007;49:1063-1069.
  8. Saab G, Young DO, Gincherman Y, et al. Prevalence of vitamin D deficiency and the safety and effectiveness of monthly ergocalciferol in hemodialysis patients. Nephron Clin Pract. 2007;105:c132-c138.
  9. Zisman AL, Hristova M, Ho LT, Sprague SM. Impact of ergocalciferol treatment of vitamin D deficiency on serum parathyroid hormone concentrations in chronic kidney disease. Am J Nephrol. 2007; 27:36-43.
  10. London GM, Guerin AP, Verbeke FH, et al. Mineral metabolism and arterial functions in end-stage renal disease: potential role of 25-hydroxyvitamin D deficiency. J Am Soc Nephrol. 2007;18:613-620.
  11. Teng M, Wolf M, OfsthunMN, et al. Activated injectable vitamin D and hemodialysis survival: a historical cohort study. J Am Soc Nephrol. 2005;16:1115-1125.
  12. Kalantar-Zadeh K, Kuwae N, Regidor DL, et al. Survival predictability of time-varying indicators of bone disease in maintenance hemodialysis patients. Kidney Int. 2006;70:771-780.
  13. Tentori F, Hunt WC, StidleyCA, et al. Mortality risk among hemodialysis patients receiving different vitamin D analogs. Kidney Int. 2006;70:1858-1865.
  14. Dhesi JK, Jackson SH, Bearne LM, et al. Vitamin D supplementation improves neuromuscular function in older people who fall. Age Ageing. 2004;33:589-595.
  15. Sato Y, Iwamoto J, Kanoko T, Satoh K. Low-dose vitamin D prevents muscular atrophy and reduces falls and hip fractures in women after stroke: a randomized controlled trial. Cerebrovasc Dis. 2005;20:187-192.
  16. Bischoff-Ferrari HA, Willett WC, Wong JB, et al. Fracture prevention with vitamin D supplementation: a meta-analysis of randomized controlled trials. JAMA. 2005;293:2257-2264. 
  17. Schleithoff SS, Zittermann A, Tenderich G, et al. Vitamin D supplementation improves cytokine profiles in patients with congestive heart failure: a double-blind, randomized, placebo-controlled trial. Am J Clin Nutr. 2006;83:754-759.
  18. Teng M, Wolf M, Lowrie E, et al. Survival of patients undergoing hemodialysis with paricalcitol or calcitriol therapy. N Engl J Med. 2003;349:446-456.
  19. Agarwal R, Acharya M, Tian J, et al. Antiproteinuric effect of oral paricalcitolin chronic kidney disease. Kidney Int. 2005;68:2823-2828.

Dr. Coyne is professor of medicine at the Washington University School of Medicine in St. Louis, Mo.

 

Conflicts of Interest: Consultant to Abbott, Watson, INEOS; Speaker for Abbott, Amgen, Watson; Research support from Abbott, Amgen, Genentech, Roche, and Watson.


From the October 01, 2007 Issue of Renal and Urology News

Topics:

Chronic Kidney Disease CKD