Use of alendronate sodium (Fosamax) to ameliorate osteoporosis in renal transplant patients: a case-control study.

BACKGROUND: Renal transplant patients often have severe bone and mineral deficiencies. While the clinical effects of immunosuppressive agents like calcineurin inhibitors (CIs) and sirolimus on bone turnover are unclear, bisphosphonates are effective in bone recovery in these patients. Gender is significantly associated with osteoporosis and affects bone turnover, which is different in women and men. The effective gender-related site of action of bisphosphonates is unknown.

METHODS: Initially, we enrolled 84 kidney recipients who had received their transplants at least 5 months ago; of these, 8 were excluded and 76 were finally included in the study. First bone mineral density (BMD) at the lumbar spine, hip, and femoral neck was determined using dual-energy X-ray absorptiometry (DXA) between September 2008 and March 2009. These 76 patients underwent a repeat procedure after a mean period 14 months. Immunosuppressive agents, bisphosphonates, patients' characteristics, and biochemical factors were analyzed on the basis of the BMD determined using DXA.

RESULTS: After the 14-month period, the BMD of lumbar spine increased significantly (from 0.9 g/cm(2) to 0.92 g/cm(2), p<0.001), whereas that of the hip and femoral neck did not. Ordinal logistic regression analysis was used to show that Fosamax improved bone condition, as defined by WHO (p = 0.007). The use of immunosuppressive agents did not affect bone turnover (p>0.05). Moreover, in subgroup analysis, Fosamax increased the BMD at the lumbar spine and the hipbone in males (p = 0.028 and 0.03, respectively) but only at the lumbar spine in females (p = 0.022).

CONCLUSION: After a long periods after renal transplantation, the detrimental effects of steroid and immunosuppressive agents on bone condition diminished. Short-term Fosamax administration effectively improves BMD in these patients. The efficacy of Fosamax differed between male and female renal transplant patients.