Estimating the Effect of Bariatric Surgery on Cardiovascular Events Using Observational Data?

Area of Science:

• Cardiology
• Metabolic Surgery
• Clinical Epidemiology

Background:

• Observational studies suggest bariatric surgery protects against cardiovascular disease.
• Existing studies often use oversimplified definitions and criteria, deviating from randomized trial standards.
• There's a need to estimate bariatric surgery's cardiovascular impact without observational data biases.

Purpose of the Study:

• To emulate two target trials using observational data to estimate the effect of bariatric surgery on cardiovascular disease.
• To compare bariatric operation versus no operation in individuals with diabetes.
• To compare preoperative preparation plus bariatric operation versus neither component.

Main Methods:

• Emulation of two target trials using observational data from US veterans with diabetes.
• Target trial 1: Bariatric surgery vs. no surgery.
• Target trial 2: Preoperative preparation and surgery vs. neither.

Main Results:

• In target trial 1 (8,087 individuals), 7-year cardiovascular risk was 18.0% (surgery) vs. 18.9% (no surgery).
• In target trial 2 (10,065 individuals), 7-year cardiovascular risk was 17.4% (surgery) vs. 18.8% (no surgery).
• Bariatric interventions reduced body mass index and hemoglobin A1c in both emulations.

Conclusions:

• Estimates from available observational data do not provide evidence that bariatric surgery reduces cardiovascular disease.
• The findings support equipoise for conducting a randomized trial on bariatric surgery for cardiovascular disease prevention.
• Further research is warranted to clarify the role of bariatric surgery in cardiovascular health.