Potential effects of 1,25-dihydroxyvitamin D3 in renal transplant recipients.

Besides its effects on bone metabolism, calcitriol has an important immunomodulatory effect, which may be protective for a renal allograft. Therefore, we evaluated the effects of oral calcitriol administration in renal transplant recipients. One hundred ten renal transplant recipients (78 men, 32 women) of mean age 35.2 +/- 11.4 years and mean posttransplantation follow-up of 50.7 +/- 22.9 months were entered into the study. Patients in group 1 (n = 57) received calcitriol therapy and patients in group 2 (n = 53) did not. The mean start of calcitriol therapy was 22.4 +/- 19.1 months posttransplantation. We restrospectively collected pretransplantation and posttransplantation laboratory and clinical data as well as creatinine levels before and after the initiation of calcitriol therapy at 6-month intervals for 2 successive years. There were no significant differences in terms of age, gender, immunosuppression, bone mineral densitometry, and follow-up. Our results showed that patients in group 1 had lower pretransplantation and postransplantation body mass index (P < .03; P < .03, respectively), lower posttransplantation third year parathyroid hormone levels (P < .02), and lower requirements for pulse steroid doses (P < .04). Using Friedman repeated measures variance test to analyze the effect of calcitriol, the increase in creatinine levels was significantly lower in group 1 (P < .04). There was no significant difference between follow-up time and calcitriol dose (P > .05). In conclusion, calcitriol therapy may reduce the rate of loss of renal function among patients receiving renal transplants.