Bariatric surgery may reduce life expectancy for super obese diabetic patients

"For most patients with diabetes and a BMI (body mass index) greater than 35, bariatric surgery increases life expectancy," says Daniel Schauer, MD, assistant professor in the Division of General Internal Medicine at UC. "However, the benefit of surgery decreases as BMI increases. The patients with a BMI over 62 likely don't gain any life expectancy with surgery."

The findings were published recently online in the Annals of Surgery.

Schauer and a team of researchers developed a decision analytic model to compare life expectancy in a group of severely obese diabetic individuals who had bariatric surgery to a group that did not have bariatric surgery. They used data involving approximately 200,000 patients from three HMO Research Network sites as well as data from the Nationwide Inpatient Sample and the National Health Interview Survey linked to the National Death Index.

In the main analyses of the study, researchers found that a 45-year-old woman with diabetes and a body mass index of 45 kg/m2 gained an additional 6.7 years of life expectancy with bariatric surgery (38.4 years with surgery versus 31.7 years without). However, the gain in life expectancy decreased once BMI hit 62 kg/m2 with bariatric surgery. Similar results were seen for both men and women in all age groups. The study did not look at differences associated with race.

"This was surprising. We expected those with higher BMIs to benefit more from bariatric surgery," says Schauer, also a UC Health physician and member of both the UC Cancer Institute and the Center for Clinical Effectiveness.

Super obese patients may have had diabetes for a longer duration and are more likely to have complications after surgery resulting in adverse health outcomes, explains Schauer.

About 15 million adults in the United States suffer from severe obesity, which is defined as having a body mass index of greater than 35 kg/m2. Obesity and diabetes are closely linked and severe obesity increases the risk of diabetes by more than seven-fold, says Schauer.