Effects of bisphosphonates on bone loss in the first year after renal transplantation - a meta-analysis of randomized controlled trials

Background. Bone loss remains a serious problem after kidney transplantation and is most pronounced during the first months after engraftment. Bisphosphonates are frequently used to treat post-transplant osteodystrophy, but data of large randomized controlled trials (RCTs) are missing. Methods. We, therefore, conducted this systematic review of the literature, searching electronical databases, reference lists and abstracts from scientific meetings to identify RCTs in all languages. The primary outcome assessed was the change in bone mineral density (BMD) during the early post-transplantation period. Based on the mean BMD change presented in the identified publications, the authors were asked for the individual BMD results of all randomized patients, determined at lumbar spine and femoral neck before and after bisphosphonate therapy. Data were pooled for summary estimates by using weighted mean differences of absolute change in BMD. An analysis of covariance was performed, adjusted for individual baseline values, treatment arm and individual trial. Results. Five studies involving 180 participants were included in our meta-analysis. Treatment with bisphosphonates showed a substantial effect in preventing post-transplant osteodystrophy. BMD decline at the lumbar spine within 6-12 months after transplantation was significantly reduced by 0.06 g/cm(2) in patients treated with bisphosphonates (95% CI 0.05-0.08 g/cm(2)). At the femoral neck, the loss of BMD was reduced by 0.05 g/cm(2) during this period (95% CI 0.0-0.11 g/cm(2)), reaching just non-statistical significance. This benefit of bone loss prevention could be reached without major side effects. Conclusion. Bisphosphonates are effective in preventing bone loss in the early post-transplant period.