Zoledronic acid increases spine bone mass and prevents hip bone loss after bariatric surgery: a randomized placebo-controlled study

Objective: The aim of this study was to investigate the effects of zoledronic acid for the prevention of bone loss after bariatric surgery. Methods: In this randomized, double-blinded study, 59 patients undergoing Roux-en-Y gastric bypass or sleeve gastrectomy (mean [SD], age: 48.9 [6.3] years, BMI: 42.3 [5.3], 73% female) were randomly assigned (1:1) to receive either zoledronic acid (5 mg; intervention [INT]) or placebo (control [CON]) preoperatively. The primary endpoint was the change in spine volumetric bone mineral density (vBMD) at 12 months after surgery. Secondary outcomes included changes in hip and femoral neck vBMD and areal BMD. Results: The estimated mean treatment effects of zoledronic acid on the spine and total hip were 6.8 mg/cm³ (95% CI 1.9–11.7; p = 0.003) and 5.0 mg/cm³ (95% CI: 1.4–8.5; p = 0.006), respectively. Bone mass in the spine increased by 2.6% in INT, whereas no changes were observed in CON. Additionally, bone loss in the total hip was prevented in INT compared with CON (vBMD: −0.6% vs. −3.6%; p = 0.006). Conclusions: Zoledronic acid increases bone mass in the spine and prevents bone loss in the hip region after bariatric surgery compared with placebo.