Bariatric surgery increases risk of bone fracture.

Introduction: The purpose of this study was to determine the long-term incidence of bone fracture after bariatric surgery, identify specific risk factors for fracture, and compare these data to baseline risk in a comorbidity-matched morbidly obese population. We hypothesize that, despite prior studies with conflicting results, bariatric surgery increases a patient's long-term risk of fracture.

Methods: All patients who underwent bariatric surgery at a single institution 1985-2015 were reviewed. Univariate analysis of patient demographic data including comorbidities, insurance payer status, procedure type, and BMI was performed. Multivariate logistic regression was used to identify independent predictors of fracture in this population. Finally, we identified a propensity-matched control group of morbidly obese patients from our institutional Clinical Data Repository in the same timeframe who did not undergo bariatric surgery to determine expected rate of fracture without bariatric surgery.

Results: A total of 3439 patients underwent bariatric surgery, with 220 (6.4%) patients experiencing a bone fracture at mean follow-up of 7.6 years. On multivariate logistic regression, independent predictors of increased fracture included tobacco use and Roux-en-Y gastric bypass while private insurance and race were protective (table). Additionally, 1:1 matching on all comorbidity and demographic factors identified 3880 patients (1940 surgical patients) with equal propensity to undergo bariatric surgery. Between the propensity-matched cohorts, patients who had a history of bariatric surgery were more than twice as likely to experience a fracture as those who did not (6.4 vs. 2.7%, p < 0.0001).

Conclusions: This study of bariatric surgery patients at our institution identified several independent predictors of postoperative fracture. Additionally, these long-term data demonstrate patients who had bariatric surgery are at a significantly increased risk of bone fracture compared to a propensity-matched control group. Future efforts need to focus on nutrient screening and risk modification to reduce the impact of this long-term complication.