Non-vertebral Fracture Risk After Gastric Bypass vs Banding

Patients who undergo Roux-en-Y gastric bypass (RYGB) surgery may be at greater risk for non-vertebral fracture than those who have adjustable gastric banding (AGB), according to a population-based study. The results were recently presented at ENDO 2018, the Endocrine Society’s 100th annual meeting in Chicago, IL.

Background
“Bariatric surgery procedures, such as RYGB, are highly effective treatments that induce sustained weight loss,” said lead author Elaine Wei-Yin Yu, MD. “RYGB leads to greater improvements in metabolic health than AGB, but RYGB also causes accelerated bone loss and may increase fracture risk.”

The study
“We found that Medicare patients who received RYGB had more fractures compared to those who received AGB. Importantly, we found that RYGB increased the risk for hip, wrist, and pelvis fractures. RYGB increased fracture risk across all age groups, in men and in women, although the effects were more pronounced among men,” said Yu, Assistant Professor of Medicine at Harvard Medical School and Director of the Bone Density Center at Massachusetts General Hospital, in Boston.

Yu and colleagues investigated the fracture rates among Medicare Parts A, B, and D enrollees with severe obesity who underwent either RYGB or AGB surgery between 2006 and 2014.

The researchers analyzed Medicare billing claims data from 50,649 adults (78% women). Of these, 35,920 underwent RYGB and 14,729 underwent AGB. The authors compared fracture rates between the 2 groups, controlling for differences in age, sex, race, geographical location, index date, degree of healthcare utilization, comorbidities, and prescribed medications.

RYGB patients were younger than AGB patients (53 vs 56 years of age), and they were more likely to have diabetes (36% vs 32%) as well as a shorter average follow-up time (3.1 vs 3.8 years).

A total of 1109 non-vertebral fractures were reported during follow-up. The estimated incidence rates of non-vertebral fractures per 1000 person-years were 9.8 in the RYGB group and 7.1 in the AGB group. Age or diabetes status did not affect RYGB-associated fracture risk.

Compared with patients who received banding, those who underwent bypass had a 126% increased risk of hip fracture, a 62% increased risk of wrist fracture, and a 172% increased risk of pelvis fracture. Gastric bypass increased overall fracture risk more dramatically in men (108%) than in women (42%).

Implications for clinicians
“This research is very relevant given the high prevalence of obesity and increasing utilization of bariatric surgery. Over one-third of adults in the United States are obese, and bariatric surgery procedures have accordingly been increasing in popularity,” Yu said. “Long-term skeletal health should be discussed and managed for all patients undergoing bariatric surgery. . . . These data also emphasize the importance of devising therapies that can counteract fracture risk after gastric bypass.”

References:

Roux-en-Y surgery linked with more non-vertebral fractures than adjustable gastric banding [press release]. Washington, DC: Endocrine Society; March 20, 2018.