Bariatric Surgery Cuts All-Cause Mortality Rate Over Many Years

SAN DIEGO –Patients who underwent bariatric surgery saw a reduction in all-cause mortality that held strong over multiple years, researchers reported.

In a retrospectives study, bariatric surgery patients were 16% less likely to die from any cause than their matched non-surgical counterparts over a median 13.2 follow-up period (hazard ratio 0.84, 95% CI 0.79-0.90, P<0.001), according to Ted Adams, PhD, MPH, of Intermountain Live Well Center in Murray, Utah.

However, surgery patients were more likely to die by suicide (HR 2.40, 95% CI 1.57-3.68, P<0.001) versus non-surgical participants, and that risk of suicide was significantly higher in those ages 18-34, he said in a presentation at ObesityWeek.

"These findings may suggest the need for more intense psychological screening before surgery and perhaps following surgery," Adams told MedPage Today, adding that "our group may be the first to suggest that the primary group to focus on for increase suicide are patients who have the surgery between ages 18 to 34."

He highlighted a 2013 study that examined several possible explanations for higher suicide risk in bariatric patients, such as feelings of hopelessness. "People who experience continued, new, or re-emergent problems associated with weight regain following bariatric surgery may feel that their last hope for a better life was dashed," Adams noted.

His group also found that surgery patients had a higher risk of mortality from liver disease versus non-surgery patients (HR 1.83, P=0.02), and the reasons for that were not clear, although it may be due to alcohol use among the patients, Adams suggested. "More research will need to be done to sort this out and confirm or refute our findings," he said.

Adams also pointed out that "patients who are severely obese have a greater than normal incidence of fatty liver disease and this condition is often improved with weight loss." He cited a 2021 JAMA study demonstrating an improvement in liver health after bariatric surgery. "Nevertheless, there was an increased morality in liver disease deaths, and this was primarily in the patients who underwent bariatric surgery when they were [ages] 18-34 years," Adams stated.

Still, he said that the overall study made it clear that "bariatric surgery has favorable long-term implications related to mortality," including a nearly three-quarters lower risk of death from diabetes.

The current results build on the research project that Adams and colleagues began more than 15 years ago, with early findings published in 2007 in the New England Journal of Medicine. For this update, they tracked 21,837 matched pairs of bariatric and non-bariatric participants from 1982-2021 for a median 13.2 years, and up to 40 years.

The bariatric patients had BMIs of ≥40 or ≥35 with co-existing comorbidities; they were all treated in Utah. They underwent gastric bypass, gastric sleeve, adjustable gastric banding, and duodenal switch procedures.

Participants were matched by sex, age, and BMI to Utah residents via driver's license records. In both groups, the average age at study entry was 42 and the average BMI was 46. However, it was not clear how many in the non-surgical group had comorbidities.

There were 2,943 all-cause deaths in the surgical group and 3,181 for in the non-surgery group. Surgery patients also saw lower risks for death (P<0.001 for all) from cardiovascular disease (-29%), cancer (-43%) and diabetes (-72%). Adams' group did not provide the number of deaths for each cause.

Adams said these shifts were most likely tied to a reduction in the risk for these diseases. "The exact clinical mechanism for remittance of some chronic diseases, such as diabetes, is under investigation and in some cases, the improvement of diabetes appears to not be just the result of significant weight loss, but due to other biochemical and biomolecular changes that are the result of the gastrointestinal surgery."

A 2020 Swedish study showed similar results with a 23% lower risk of death in bariatric patients versus those who received usual obesity care over a median 24-year follow-up.

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