Zoledronic acid versus alendronate for the prevention of bone loss after heart or liver transplantation.

Context: The first year after transplantation is characterized by rapid bone loss.

Objective: The aim of this study was to compare zoledronic acid (zoledronate) and alendronate for prevention of transplantation bone loss.

Design And Setting: A randomized clinical trial was conducted at a transplantation center.

Patients: The study included 84 adults undergoing heart or liver transplantation and a concurrently transplanted, nonrandomized reference group of 27 adults with T scores greater than -1.5.

Interventions: Alendronate (70 mg weekly for 12 months) or one 5-mg infusion of zoledronate were both initiated 26 ± 8 d after transplantation.

Main Outcome Measures: The primary outcome was total hip bone mineral density (BMD) 1 yr after transplantation. Secondary outcomes included femoral neck and lumbar spine BMD and serum C-telopeptide, a bone resorption marker.

Results: In the reference group, BMD declined at the spine and hip (P < 0.001). In the randomized groups, hip BMD remained stable. Spine BMD increased in the zoledronate group and did not change in the alendronate group; at 12 months, the 2.2% difference between groups (95% confidence interval, 0.6 to 3.9%; P = 0.009) favored zoledronate. In heart transplant patients, spine BMD declined in the alendronate and increased in the zoledronate group (-3.0 vs. +1.6%, respectively; between-group difference, 4.2%; 95% confidence interval, 2.1 to 6.3%; P < 0.001). In liver transplant patients, spine BMD increased comparably in both groups. Twelve-month C-telopeptide was lower in the zoledronate group than in the alendronate group (79 vs. 49%; P = 0.04).

Conclusions: One 5-mg infusion of zoledronate and weekly alendronate prevent bone loss at the hip and, in liver transplant patients, increase spine BMD. In heart transplant patients, spine bone BMD remained stable with zoledronate but decreased with alendronate.