Alendronate prevents further bone loss in renal transplant recipients

The aim of this study was to investigate the effects of alendronate, calcit riol, and calcium in bone loss after kidney transplantation. We enrolled 40 patients (27 men and 13 women, aged 44.2 +/- 11.6 years) who had received renal allograft at least 6 months before (time since transplant, 61.2 +/- 4 4.6 months). At baseline, parathyroid hormone (PTH) was elevated in 53% of the patients and the Z scores for bone alkaline phosphatase (b-ALP) and uri nary type I collagen cross-linked N-telopeptide (u-NTX) were higher than ex pected (p < 0.001). T scores for the lumbar spine (-2.4 +/- 1.0), total fem ur (-2.0 +/- 0.7), and femoral neck (-2.2 +/- 0.6) were reduced (p < 0.001) . After the first observation, patients were advised to adhere to a diet co ntaining 980 mg of calcium daily and their clinical, biochemical, and densi tometric parameters were reassessed 1 year later. During this period, bone density decreased at the spine (-2.6 +/- 5.7%; p < 0.01), total femur (-1.4 +/- 4.2%; p < 0.05), and femoral neck (-2.0 +/- 3.0%; p < 0.001). Then, th e patients were randomized into two groups: (1) group A-10 mg/day of alendr onate, 0.50 mug/day of calcitriol, and 500 mg/day of calcium carbonate; and (2) group B-0.50 mug/day of calcitriol and 500 mg/day of calcium carbonate . A further metabolic and densitometric reevaluation was performed after th e 12-month treatment period. At the randomization time, group A and group B patients did not differ as to the main demographic and clinical variables. After treatment, bone turnover markers showed a nonsignificant fall in gro up B patients, while both b-ALP and u-NTX decreased significantly in alendr onate-treated patients. Bone density of the spine (+5.0 +/- 4.4%), femoral neck (+4.5 +/- 4.9%), and total femur (+3.9 +/- 2.8%) increased significant ly only in the alendronate-treated patients. However, no trend toward furth er bone loss was noticed in calcitriol and calcium only treated subjects. N o drug-related major adverse effect was recorded in the two groups. We conc lude that renal transplanted patients continue to loose bone even in the lo ng-term after the graft. Alendronate normalizes bone turnover and increases bone density. The association of calcitriol to this therapy seems to be ad vantageous for better controlling the complex abnormalities of skeletal met abolism encountered in these subjects.