Treatment with intermittent calcitriol and calcium reduces bone loss after renal transplantation.

Randomized trial in adult kidney transplant recipients with a first or second graft and no prior parathyroidectomy. In the calcitriol plus calcium group, 45 participants were randomized and 36 were analyzed at 1 year after transplantation.

Adults with renal transplantation received oral calcium lactogluconate providing 0.5 g elemental calcium daily for 1 year. The active arm also received oral intermittent calcitriol, 0.5 microg every other day for the first 3 months after transplantation, versus calcium plus placebo in the comparator arm.

Calcitriol plus calcium was associated with less early post-transplant bone loss and a faster fall in parathyroid hormone than calcium alone. At 3 months, PTH was 61.4 ± 42.2 pg/mL versus 85.7 ± 53.1 pg/mL (P = 0.02), and total hip BMD change was 0.04 ± 3.3% versus -1.93 ± 3.2% (P = 0.01). At 12 months, total hip BMD remained better preserved with calcitriol (0.32 ± 4.8% vs -2.17 ± 4.4%, P = 0.03), with significant differences also at the intertrochanter, trochanter, and Ward’s triangle, but not the femoral neck. The genotype effect was stronger in carriers of the at-risk VDR B allele, and hypercalcemic episodes were uncommon (2 patients, 4.4%, vs 4 patients, 9.8%).

The analyzed sample at 1 year was smaller than the randomized sample, which reduces precision. The study was conducted in a Spanish transplant population, limiting generalizability. Benefits were not uniform across skeletal sites and appeared influenced by VDR genotype, so the effect may not apply equally to all recipients.