A controlled study of vitamin D3 to prevent bone loss in renal-transplant patients receiving low doses of steroids

Background. New and potent immunosuppressive regimens allow for reduced doses of corticosteroids after renal transplantation. The aims of our study were to investigate whether the use of low-dose corticosteroids is associated with a reduction in posttransplant bone loss and to assess the ability of cholecalciferol supplementation to further decrease bone loss in this setting. Methods. Ninety patients admitted for renal transplantation and scheduled to be treated per protocol with low doses of prednisolone were randomized to receive either 400 mg daily oral calcium (Ca group, n=44) or the same dose of calcium in association with a monthly dose of 25,000 IU of vitamin D3 (CaVitD group, n = 46). Bone mineral density (BMD) was measured by dual energy absorptiometry at baseline and at 1 year. Results. The overall population experienced a moderate but significant -2.3 +/- 0.9 % loss of lumbar spine BMD (P<0.01) but no bone loss at the femoral neck and shaft during the first posttransplant year. Bone loss tended to be slightly higher in the CaVitD group, but the difference did not reach statistical significance. Patients in the CaVitD group had significantly higher 25(OH) but not 1,25(OH), vitamin D levels. We observed a highly significant negative correlation between 25(OH) vitamin D and intact parathyroid hormone (iPTH) serum levels. Conclusions. Kidney-transplant recipients receiving modern immunosuppressive regimens with low doses of corticosteroids experience only minimal loss of BMD during the first posttransplant year. Cholecalciferol supplementation did not prevent posttransplant bone loss but contributed to the normalization of iPTH levels after renal transplantation.