Abstract

Introduction

Vitamin D deficiency is prevalent in kidney transplant recipients (KTR) and recommendations on how to replenish vitamin D deposits are scarce.

Aim

To evaluate, in KTR, the safety and efficacy of calcifediol in two different vitamin D supplementation regimens, in order to assess the most suitable dose.

Patients and methods

Prospective observational study with two calcifediol supplementation regimens randomly prescribed by clinicians in liquid form, at 266 mcg doses, monthly or biweekly. We analyzed 168 KTR with a functioning allograft for more than 6 months. Patients receiving other vitamin D forms, calcimimetics or bisphosphonates were excluded. Before calcifediol initiation (pre-treatment levels) and after at least 3 months of treatment (post-treatment levels), we measured serum levels of 25-OH vitamin D (25(OH)D), parathyroid hormone (PTH), alkaline phosphatase (ALP), calcium (sCa), phosphate (sPO4) and creatinine (sCreat).

Results

In the monthly group (n = 72), 25(OH)D levels increased from 14 ng/ml [interquartile range, IQR 9–22] at baseline to 31 [20–38] (p = 0.000), PTH decreased from 124 pg/ml [87–172] to 114 [78–163] (p = 0.006), while sCa and sPO4 remained stable. In the biweekly group (n = 96), 25(OH)D increased from 14 ng/ml [9–20] at baseline to 39 [28–52] (p = 0), PTH decreased from 141 pg/ml [95–221] to 112 [90–180] (p = 0.000), sCa remained stable and sPO4 increased from 3.3 ± 0.6 mg/dl to 3.5 ± 0.6 (p = 0.003). Renal function remained stable in both groups.

Conclusion

Vitamin D reposition with oral calcifediol, in a biweekly or monthly regimen, is safe and effective in improving 25(OH)D blood levels and in decreasing PTH in kidney transplant recipients.