Background: Vitamin D deficiency is common in CKD and dialysis patients. Studies suggest a physiologic autocrine and/or paracrine role for 1,25(OH)D produced via 1α-hydroxylase in tissues such as vascular smooth muscle, breast, prostate, and bone marrow. Studies have not yet defined the optimal dose and duration of vitamin D necessary to replete and maintain stores in dialysis patients, or whether it is safe or beneficial. Methods: We performed a review of the prevalence of vitamin D deficiency and the safety and effectiveness of ergocalciferol oral supplementation (vitamin D₂, 50,000 IU monthly) given to hemodialysis patients during dialysis May to October 2005 in St. Louis (latitude 38°). Results: Among the 119-patient cohort present for the entire 6 months, 25(OH)D was (mean ± SD) 16.9 ± 8.5 ng/ml, (91% < 30 ng/ml) and increased to 53.6 ± 16.3 ng/ml (p < 0.001), (95% > 30 ng/ml, and none > 100 ng/ml). Initial versus 6 mo. serum calcium (9.1 ± 0.56 vs. 9.2 ± 0.70), phosphorus (5.25 ± 1.38 vs. 5.11 ± 1.31), Ca × P, and paricalcitol dose (10.3 ± 9.6 vs. 11.3 ± 9.2 mcg/week) were not significantly different. No hypercalcemia could be attributed to supplementation. Mean hemoglobin did not change significantly (11.96 ± 1.4 vs. 11.69 ± 1.4, p = 0.124), but most patients experienced a reduced weekly epoetin dose. Epoetin dose decreased in 64% of patients, and increased in 28%. Conclusions: We conclude that the vast majority of hemodialysis patients are vitamin D-deficient; monthly ergocalciferol 50,000 IU is safe and effective in normalizing serum 25(OH)D levels and may have an epoetin-sparing effect.

Secondary hyperparathyroidism is common among dialysis patients and leads to numerous complications including cardiovascular disease and renal osteodystrophy. Cinacalcet, an oral daily calcimimetic agent that sensitizes the calcium receptor to serum calcium, is approved for treatment of secondary hyperparathyroidism in dialysis patients. We identified 101 patients who received their first cinacalcet prescription between November 2004 and April 2005. All patients were participating in a Missouri state-funded pharmacy program providing free or low cost medications. We tracked the cinacalcet refill rate and refills for another control medication prescribed to each patient. The average cinacalcet refill rate over the first 12 months was 56% vs. 64% for the control medication (P=0.02). Good adherence, defined as >80% medication possession ratio over the 12 months, was 29% for cinacalcet and 33% for the control medication (P=0.68). Additionally, the refill rate for cinacalcet fell significantly over five quarterly periods from 53% in the first quarter to 37% in the 5th quarter. We conclude that dialysis patients' adherence to medications, including cinacalcet, is poor even when medications are provided at a nominal cost. Poor cinacalcet adherence would be expected to impair long-term control of SHPT. In a reimbursement system where injectable, but not oral medications, are bundled with dialysis payments there may be pressure to move patients to oral medications. The poor compliance found in this study highlights the potential adverse effects of movement toward self-administered oral therapy.

No abstract