Comprehensive Study, Boasting 40 Years of Follow-up, Underlines Long-Term Benefits of Bariatric Surgery

Ted Adams, PhD, MPH

Leveraging 40 years of follow-up data, a retrospective study is providing insight into durability of effects and magnitude of risk reduction provided by bariatric surgery.

Using data from 21,837 matched surgery and nonsurgery pairs, results of the study indicate risk of all-cause mortality was 16% lower in those who underwent a bariatric procedure compared to their counterparts who did not, with results also pointing to a 29% reduction in risk of cardiovascular disease mortality and a 72% reduction in risk of diabetes-related mortality. However, investigators point to cause for concern over the risk of suicide, which was 2.4 times greater in the surgery group.

“Results of this study attest to the decades-long durability of bariatric surgery in reducing death from all causes and reducing deaths related to cardiovascular disease, cancer, and diabetes when compared with matched participants with severe obesity,” wrote investigators. “In addition, favorable mortality outcomes were evident for major bariatric surgery procedures. Serious concern, however, continues to be exhibited regarding increased mortality following bariatric surgery in relation to suicide, accidents, and cirrhosis of the liver.”

Led by Ted D. Adams, PhD, MPH, of the University of Utah and Intermountain Healthcare, the current study was launched with the intent of capturing and reporting data related to long-term mortality among patients who have undergone bariatric surgery. With this in mind, the study was designed as a retrospective study of data from within the Utah Population Database, which includes linked, population-based information from Utah with statewide birth and death certificates, driver licenses and ID cards, and voter registration cards. From the database, which maintains links between the database and the medical records held by the 2 largest health care providers in Utah, investigators identified a cohort of more than 27,000 with a history of bariatric surgery between 1982 and 2018 for inclusion in their study.

For the purpose of analysis, those who had undergone bariatric surgery were matched in a 1:1 ratio based on age, sex, BMI, and surgery date with a driver license application/renewal date. The outcome of interest for the study were all-cause mortality and cause-specific mortality, including risk mortality related to cardiovascular disease, cancer, and diabetes. Investigators pointed out mortality rates were estimated using Cox regression and stratified according to patient sex, surgery type, and age at surgery.

After matching, investigators identified a cohort of 21,837 matched surgical and nonsurgical pairs for inclusion in their study. For the nonsurgical cohort, the mean age at index was 42.3 (SD, 11.9) years, the mean BMI at index date was 46.2 (SD, 6.8) kg/m2, 87.6% of the cohort was White, and 79.1% were female. For the surgical cohort, the mean age at index was 42.2 (SD, 11.7) years, the mean BMI at index date was 46.0 (SD, 8.3) kg/m2, 94.4% of the cohort was White, and 79.1% were female. The mean follow-up time for the study cohort was 13.2 (SD, 9.5) years.

Upon analysis, results indicated undergoing bariatric surgery was associated with a 16% reduction in risk of all-cause mortality relative to those who did not undergo bariatric surgery (HR, 0.84 [95% CI, 0.70-0.90]; P <.001). Analysis of cause-specific mortality indicated a significantly lower mortality rate was observed in the bariatric surgery group compared to their counterparts who did not undergo surgery, with reductions of 29%, 43%, and 72% for cardiovascular disease, cancer, and diabetes, respectively. However, investigators highlighted an apparent increase in risk of suicide, with results suggesting patients who underwent bariatric surgery had a more than 2-fold increase in risk compared to their counterparts who did not undergo surgery. Further analysis indicated this risk was most apparent among those who underwent surgery between 18 and 34 years of age.

“This important study adds to the mounting evidence that bariatric surgery, not only improves quality of life for patients, but will also increase their life expectancy. This work will hopefully improve patients’ access to this effective treatment for obesity, which is still limited to only one percent of qualified patients. Also, the study highlights the importance of providing more resources for pre-surgical psychological screening and post-surgery follow up, especially for younger patients,” said Jihad Kudsi, MD, of the Bariatric Surgery Division of Duly Health and Care, who was not associated with the research, in a statement from The Obesity Society.

This study, “Long-term All-Cause and Cause-Specific Mortality for Four Bariatric Surgery Procedures,” was published in Obesity.