There was a greater risk for fracture among patients undergoing bariatric surgery when compared to obese or non-obese controls, a recent study found, and this risk remained higher after surgery. This case-controlled study included 12,767 patients who underwent bariatric surgery, and were age and sex matched with 38,028 obese and 126,760 non-obese controls. Fracture risk was also compared before and after surgery within each group and by type of surgery from 2006 to 2014. Researchers found:

• Prior to surgery, patients undergoing bariatric surgery were more likely to fracture vs obese or non-obese controls.

• A mean of 4.4 years after surgery, bariatric patients were still more susceptible to fracture (4.1%) than were obese (2.7%) and non-obese (2.4%) controls.

• Postoperative adjusted fracture risk was higher in the bariatric group than in the obese (RR 1.38) and non-obese (RR 1.44) groups.

• Fracture risk was site specific and changed from a pattern associated with obesity to a pattern typical of osteoporosis after surgery.

Citation: Rousseau C, Jean S, Gamache P, et al. Change in fracture risk and fracture pattern after bariatric surgery: nested case-control study. [Published online ahead of print July 27, 2016]. BMJ. doi:10.1136/bmj.i3794.

Commentary: This study shows that very obese patients have a higher fracture risk compared to obese or non-obese individuals. The reasons for this are not entirely clear but may be due to increased stress on the bone, vitamin D deficiency, or falls. The type of fracture changed from primarily lower limb fractures to fractures more typical of osteoporotic fractures after surgery, suggesting systematic changes in bone metabolism after bariatric surgery. This is helpful information as part of the risk/benefit discussion for patients contemplating bariatric surgery. —Neil Skolnik, MD