Long-Term Benefits and Risks of Weight Loss Surgery for Obesity and Type 2 Diabetes

Adults managing obesity and type 2 diabetes find that specific types of metabolic and bariatric surgery, notably gastric bypass procedures, offer distinct long-term improvements in body weight and blood sugar control, according to a systematic review updated in June 2024.

Obesity is characterized by excess fat deposits that can damage health, while type 2 diabetes impairs the body’s ability to control blood sugar levels because insulin fails to work properly. These conditions frequently occur together, raising the risk of cardiovascular disease and premature death. While initial treatments typically involve lifestyle interventions like nutrition, exercise, behavioral programs, and medications, surgery is often considered when these approaches fall short.

To determine the safest and most beneficial interventions, researchers examined studies involving adults with obesity and type 2 diabetes. They utilized a network meta-analysis to evaluate and compare different surgical procedures—including gastric banding, gastric sleeve, Roux-en-Y gastric bypass, one-anastomosis gastric bypass, and gastric plication—against each other and against non-surgical treatments.

Long-Term Benefits of Gastric Bypass Procedures

The review identified 18 studies encompassing 15,282 participants. Among these, 13 studies involving 911 people used randomized designs, while 5 observational studies included 14,371 participants to provide real-world data.

According to the findings, Roux-en-Y gastric bypass may improve body weight and likely reduce waist circumference over the long term—defined as at least five years of follow-up—when compared with lifestyle and medication therapy. Furthermore, Roux-en-Y gastric bypass may improve long-term blood sugar levels and potentially reduce type 2 diabetes complications compared to non-surgical treatments, though the evidence for complications carries significant uncertainty.

Other surgical methods also show potential benefits, though with varying degrees of certainty. One-anastomosis gastric bypass and, to a lesser extent, gastric sleeve procedures may improve body weight and waist circumference, yet researchers remain very uncertain about those specific results. Similarly, one-anastomosis gastric bypass, gastric sleeve, and gastric banding may improve type 2 diabetes status, but the certainty of this evidence is also rated as very low.

Safety Risks and Evidence Limitations

Uncertainty remains regarding the comparative risks of these operations. The review found it unclear whether different surgical procedures have a definitive effect on serious unwanted health effects or death from any cause at least five years post-surgery.

While Roux-en-Y gastric bypass and gastric sleeve procedures may lead to a greater increase in health-related quality of life than non-surgical care, researchers express high uncertainty regarding these outcomes as well. The overall confidence in the evidence is often low to very low. This limitation stems from small participant numbers in randomized trials and very few recorded events for serious health complications, deaths, and diabetes-related issues.