Studies suggest that bariatric surgery is associated with lower mortality rates compared with GLP-1 drugs, but…

An observational, retrospective cohort study from Israel found that in people with obesity and diabetes, weight-loss metabolic surgery was associated with a greater reduction in mortality compared with first-generation GLP-1 receptor agonists, if diabetes duration was 10 years or less.

Dr. Orna Reges and colleagues from Ariel University in Israel reported that over a median follow-up of 6.8 years, bariatric surgery was associated with a 62% reduction in mortality compared with GLP-1 agonists in patients with short duration of diabetes (HR 0.38, 95% CI 0.25-0.58).

However, when considering maximum change in body mass index (BMI), this association became non-significant (HR 0.79, 95% CI 0.43-1.48).

“The fact that the survival advantage disappeared after adjusting for maximum weight loss during follow-up suggests that the association between treatment type and all-cause mortality is mediated by the amount of weight loss,” the authors wrote. JAMA Network Open.

For patients with diabetes duration of 10 years or more, which represented approximately one-fifth of the study cohort, bariatric surgery did not confer a survival advantage compared with GLP-1 agonists (HR 0.65, 95% CI 0.39-1.08), despite a greater long-term reduction in BMI with GLP-1 agonists (change from baseline -21.9% vs. -7.2%).

“This finding may be explained by the adverse effects of long-term diabetes duration masking any benefits associated with weight loss,” the researchers explained. “This result is consistent with previous reports of a high prevention of diabetic complications after BMS.” [bariatric metabolic surgery] Among people who have had diabetes for a short period of time.”

The researchers added that other factors, such as increasing age and the small sample size of patients with longer duration of diabetes, may also have contributed to the lack of association.

Neither treatment significantly reduced the risk of major nonfatal cardiovascular events, such as myocardial infarction, stroke, or ischemic heart disease.

• Diabetes duration 10 years or less: HR 0.74 (95% CI 0.49-1.10)
• Diabetes duration ≥10 years: HR 1.21 (95% CI 0.80-1.85)

Of note, this analysis only included first-generation GLP-1 agonists, namely liraglutide (Victoza, 61.9%), dulaglutide (Trulicity, 21.2%), exenatide (Byetta, Bydureon, 13.6%), lixisenatide (1.4%), insulin degludec and liraglutide (1.6%), and insulin degludec and lixisenatide (0.3%). The study did not include newer agents such as semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound), which are known for their more pronounced weight loss effects.

Regis and his colleagues used electronic health record data from Clalit Health Services, Israel’s largest healthcare provider, to study 6,070 members aged 24 years or older who had been diagnosed with diabetes after age 21. All had a BMI of 30 or higher. They had undergone bariatric surgery or been administered GLP-1 receptor agonists between January 2008 and December 2021, and were matched 1:1 for age, sex, and clinical characteristics.

The mean age was 51 years, and 64.9% were women. Most had hyperlipidemia and/or hypertension at baseline. The mean Hba1c levels at baseline were significantly higher in GLP-1 agonist users than in surgical patients (9.1% vs. 7.5%). Exclusion criteria included a history of cancer diagnosis within the past 2 years, end-stage renal disease, pregnancy, ischemic heart disease, ischemic stroke, or congestive heart failure.

Bariatric surgeries included laparoscopic banding (12.4%), Roux-en-Y gastric bypass (46.4%), and laparoscopic sleeve gastrectomy (41.2%).GLP-1 agonists were taken for at least 6 months within a consecutive 12-month period.

Models were adjusted for diabetes duration, age, ethnicity, BMI, HbA1c levels, socioeconomic status, diagnosis of atrial fibrillation, hyperlipidemia, hypertension, smoking status, and use of renin-angiotensin system drugs, lipid-modifying agents, insulin, SGLT2 inhibitors, and other hypoglycemic agents.

Each type of bariatric surgery was not compared with a type of GLP-1 receptor agonist, which Reyes and colleagues noted is a limitation of the study. Additionally, patients who switched treatments were excluded, although initiation of GLP-1 agonist use after bariatric surgery could be a sign that the surgery was not successful.