Research

Energy balance

Roux-en-Y gastric bypass (RYGB) reduces all-cause and cardiovascular mortality in obese individuals with type 2 diabetes primarily through weight reduction (BMI decrease), rather than through improvements in glycemic control (HbA1c), blood pressure, or lipid profiles.

For obese individuals with type 2 diabetes, Roux-en-Y gastric bypass significantly reduces the risk of death, primarily by lowering body weight. While blood sugar, blood pressure, and cholesterol often improve after surgery, these improvements do not appear to be the main reason for the longevity benefit. The weight loss itself is the key driver, acting as a proxy for reduced mechanical stress and inflammation. Therefore, achieving and maintaining significant weight loss is critical for mortality reduction in this population.

GoodQualifiesHIGH confidence
The causal mediation analysis suggests that RYGB has a positive effect on mortality risk mainly by means of weight reduction (as opposed to changes to the risk factors analyzed).
Vasileios Liakopoulos et al. · BMJ Open Diabetes Research & Care · 2017

Why this rating

Large nationwide matched observational cohort (n=12,264) with causal mediation analysis, though observational design limits causal inference compared to RCTs.

Source

Changes in risk factors and their contribution to reduction of mortality risk following gastric bypass surgery among obese individuals with type 2 diabetes: a nationwide, matched, observational cohort study

Vasileios Liakopoulos et al. · BMJ Open Diabetes Research & Care · 2017

DOI 10.1136/bmjdrc-2016-000386

cohort · n=12264Cited 10×
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DOI resolved against Crossref · corpus check 2026-06-10

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