Fractures in Adults After Weight Loss from Bariatric Surgery and Weight Management Programs for Obesity: Systematic Review and Meta-analysis

Background
Weight loss interventions for obesity, such as bariatric surgery, are associated with reductions in bone mineral density and may increase the risk of fractures. We undertook a systematic review and meta-analysis of bariatric surgery and lifestyle weight management programs (WMPs) with fracture outcomes.

Methods
We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials from 1966 to 2018, and our trial registry of WMP randomized controlled trials (RCTs). We included RCTs, non-randomized trials, and observational studies of bariatric surgery, and RCTs of WMPs. Studies had follow-up ≥ 12 months, mean group body mass index ≥ 30 kg/m2. The primary outcome measure was incidence of any type of fracture in participants, and the secondary outcome was weight change. We used random effects meta-analysis for trial data.

Results
Fifteen studies were included. Three small trials provided short-term evidence of the association between bariatric surgery and participants with any fracture (365 participants; RR 0.82; 95% CI 0.29 to 2.35). Four out of six observational studies of bariatric surgery demonstrated significantly increased fracture risk. Six RCTs of WMPs with 6214 participants, the longest follow-up 11.3 years, showed no clear effect on any type of fracture (RR 1.04; 95% CI 0.91 to 1.18), although authors of the largest RCT reported an increased risk of frailty fracture by their definition (RR 1.40; 95% CI 1.04 to 1.90).

Conclusion
Bariatric surgery appears to increase the risk of any fracture; however, longer-term trial data are needed. The effect of lifestyle WMPs on the risk of any fracture is currently unclear.