Bariatric Surgery Significantly Increases Fracture Risk

Bariatric surgery has given hundreds of thousands of severely overweight people, who had little or no success achieving a healthy weight through traditional methods, a new lease on life. By restricting food intake and, in some operations, interrupting the digestive process to prevent the absorption of some calories and nutrients, the procedure not only promotes weight loss but also improves or resolves conditions such as type 2 diabetes, high blood pressure, high blood cholesterol, obstructive sleep apnea, and gastroesophageal reflux disease (GERD). Recent studies suggest that bariatric surgery may even have a favorable impact on mortality rates in severely obese patients.

Of course, as with any surgical procedure, there is the risk of complications, including wound infections, bleeding, breathing problems, hernias, and leaks from the staple lines, ulcers or strictures at the connection between the stomach pouch and small intestine and blood clots. Even after the initial post-surgery risks have passed, there are long-term risks. Up to one-third of patients develop gallstones and nearly 30 percent develop nutritional deficiencies such as anemia, osteoporosis, and metabolic bone disease. And now, researchers say there is another long-term concern for patients having bariatric surgery—a significantly increased risk of broken bones.

Previous studies have shown that bariatric surgery results in an increased bone turnover, the rate of bone breakdown and bone formation. Suspicion that this could cause an increased risk of fractures prompted researchers at the Mayo Clinic in Rochester, Minnesota to begin analyzing available medical records of the 292 patients who underwent bariatric surgery at their facility between 1985 and 2004. The majority, 90 percent, of the patients had gastric bypass surgery, while the other patients had either gastric band surgery or biliopancreatic diversion.

After reviewing 97 cases (86 women; average age of 44), the researchers found that within an average of seven years following surgery, there were 31 fractures reported in 21 patients. When compared to individuals of the same age and sex in the general population, those having bariatric surgery were 1.8 times more likely to have a first fracture at any site of the body. Fractures were reported in the upper arms, hip, and spine, but fractures at the hand and foot were the most elevated, with an increase of more than three times and almost four times, respectively, greater than average. “We knew there was a dramatic and extensive bone turnover and loss of bone density after bariatric surgery,” said Dr. Jackie Clowes, an assistant professor of medicine at Mayo. “But we didn’t know what that meant in terms of fractures.”
 
The researchers did not have a precise explanation for the increase. “It is currently unclear why fractures are more common after bariatric surgery, especially at the hand and foot,” said Dr. Clowes. “There are data suggesting that obesity appears to protect against fracture. Given this, it would suggest that it is a complication of the procedure itself that leads to fractures.” She added that, “although aggressive calcium and vitamin D supplementation after (bariatric) surgery may well help, it may still be insufficient to prevent the increased risk of fracture.”

Dr. Elizabeth Haglind, Mayo endocrinologist and lead author, who presented the findings at The Endocrine Society’s 91st Annual Meeting in Washington, D.C., said that “more research is needed to confirm our findings.” The team plans to examine data on the remaining patients who had bariatric surgery and hope to conduct additional studies that will help them “understand the specific risk factors and mechanisms involved.”