Clodronate treatment of established bone loss in cardiac recipients: a randomized study.

BACKGROUND: Bone loss has been reported as a complication after heart transplantation (HTx), and the increase in bone fractures is an effective problem. Treatment of osteoporosis has obtained mixed results. In this study we evaluate the effect of treatment with an oral bisphosphonate. METHODS: Sixty-four patients with low mineral density 6 months after HTx were randomized as follows: Group A received oral clodronate (1600 mg/day in two divided doses), and Group B received placebo. Every patient was also treated with 2000 mg/day of oral calcium carbonate. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry at the lumbar spine, 1/3 and 1/10 of the distal nondominant forearm before and after 12 months of treatment. Laboratory tests were performed at 3, 6, and 12 months of treatment. RESULTS: All patients demonstrated manifest bone loss 6 months after HTx compared with normal non-HTx controls (P=0.0001). After 1 year of clodronate therapy, BMD at the lumbar spine increased from 0.77+/-1.4 g/cm(2) to 0.86 g/cm(2) (P=0.02). Laboratory tests did not show any significant variation, except for the bone isoenzyme of alkaline phosphatase, which showed a significant decrease after 1 year of treatment. The incidence of new fractures was 9.3% in the placebo group and 0% in the clodronate group. Therapy was well tolerated without impact on graft function. CONCLUSIONS: One year of clodronate therapy induced a significant increase in BMD at the lumbar spine in our HTx patients. Treatment was well tolerated without onset of new bone fractures.