Increased Fracture Risk After Bariatric Surgery: a Case-Controlled Study with a Long-Term Follow-Up

Abstract

Purpose: Bariatric surgeries are common procedures due to the high prevalence of obesity. This study aimed to investigate whether bariatric surgery increases fracture risk.

Material and methods: It was a case-controlled study. Patients who underwent bariatric surgery during 2011 and 2012 were matched for age (± 5 years) and gender to patients on medical weight management during the same period with a ratio of 1:2. The index date was defined as the date of bariatric surgery for both groups. The subject's electronic medical records were reviewed retrospectively to identify fractures documented by radiology during January 2020.

Results: Randomly selected 403 cases were matched to 806 controls with a median age of 36.0 years (IQR 14.0) and 37.0 years (IQR 14.0), respectively. Seventy per cent of the cohort were females. Eighty per cent received sleeve gastrectomy, and the remaining (17%) underwent gastric bypass. The mean duration of follow-up was 8.6 years. The fracture rate was higher in the surgical group as compared to the controls (9.4% vs 3.5%) with a crude odds ratio of 2.71 (95% CI 1.69-4.36). The median duration for time to fracture was 4.17 years for the surgical group and 6.09 years for controls (p-value = 0.097). The most common site of fractures was feet, followed by hands. Apart from a few wrist fractures, there was no typical osteoporotic sites fracture.

Conclusion: Subjects who underwent bariatric procedures had more non-typical osteoporotic site fractures affecting mainly feet and hands, and fractures tend to occur earlier as compared to controls.

Keywords: Bariatric surgery; Fracture; Malabsorption; Obesity; Osteoporosis.

Fig. 1

The surgical group (red) developed their fractures much earlier than controls (blue) with the largest gap in cumulative hazard was at 6 years