1,25-dihydroxyvitamin D(3) therapy is protective for renal function and prevents hyperparathyroidism in renal allograft recipients.

1,25-Dihydroxyvitamin D(3) (calcitriol) therapy has been extensively used for posttransplant osteoporosis. Beside its effect on bone metabolism, calcitriol has an important immunomodulatory effect. We evaluated the effects of oral calcitriol therapy on allograft function and parathyroid hormone levels after renal transplantation. The patients were retrospectively selected from a renal transplant patient population who received calcitriol (group 1, n = 59, 36 male/23 female, follow-up: 52.8 +/- 12.2 months) compared with group (group 2, n = 52, 42 male/9 female, follow-up: 62.0 +/- 24.4 months) without calcitriol therapy after renal transplantation. Calcitriol therapy was started 24.0 +/- 19.1 months posttransplantation. All patients were under three-drug immunosuppression. The pretransplant and posttransplant data were studied retrospectively. Additionally, creatinine levels before and after the initiation of calcitriol therapy were recorded at 6 months intervals for 3 successive years. Our results were analyzed according to the first and third year on therapy data. According to the first year data, there were no differences in patient groups in terms of creatinine and iPTH levels. In the third year, the patients in group 1 showed significantly lower creatinine (P = .01) and iPTH (P < .04) levels and needed lower pulse steroid doses (P < .04). According to a Friedman repeated measures variance test, the creatinine level was significantly lower among group I (P < .04) at 3-year follow-up. In conclusion, even a delayed start of calcitriol therapy after renal transplantation exerts a protective effect on renal allograft function and prevents the development of hyperparathyroidism.