The Hidden Risk of Bariatric Surgery at BMI 50+
Summary: A new study presented at the ASMBS 2025 documents a steep increase in postoperative complications among bariatric patients with a BMI over 50. The risk of complications was more than 500% higher by moving from the lowest to the highest BMI group. The study provides valuable information for safer surgery planning with the argument that bariatric surgery per se is safe, but the risk increases acutely if severe obesity is present.
Does a Higher BMI Mean Higher Risk? New Data Says Yes
Bariatric surgery is widely regarded as safe and effective as a method of treating obesity. But what impact does body mass index (BMI) have on outcomes after surgery?
During the 2025 American Society for Metabolic and Bariatric Surgery (ASMBS) Annual Scientific Meeting, a significant study revealed a disturbing trend: the higher the BMI, the higher the complication risk, particularly in those with a BMI of 50 or above.
What the Study Found: A 536% Jump in Complication Risk
In a retrospective review of more than 665,000 bariatric procedures conducted in 2020-2023, authors examined the MBSAQIP database to contrast rates of complications by BMI.
Primary findings:
- The risk of complications was enhanced by 536% from the lowest to the highest BMI group.
- Severe complications were increased by 3.21% in patients with a BMI ≥50.
- BMI 50 was a turning point for rising risk of morbidity and mortality.
“Obesity itself raises surgical risks, but BMI over 50 clearly amplifies those risks in bariatric procedures,” said Dr. John Scott, co-author and Chief of Minimal Access and Bariatric Surgery at Prisma Health, SC.
Bariatric Surgery: Still Among the Safest Options
In spite of the heightened risk in the super obese patient, bariatric surgery is still a low-risk operation overall. Its safety profile is on par with that of common procedures like:
- Gallbladder removal
- Appendectomy
- Knee replacement
“The complication rates are still low overall. This study provides granular insights to help improve surgical counselling and outcomes,” noted Dr. Richard Peterson, President-elect of ASMBS, who was not involved in the research.
Why Bariatric Surgery is Important
Metabolic and bariatric surgery, such as gastric bypass and sleeve gastrectomy, does more than induce weight loss. They:
- Improve or reverse Type 2 diabetes, heart disease, and high blood pressure
- Achieved long-term, sustainable outcomes
- Are now the most effective treatment for severe obesity
More than 270,000 procedures were performed in 2023 in the U.S., just 1% of the eligible population.
Understanding Obesity: A Public Health Crisis
According to the CDC, the current obesity statistics in the U.S. are:
- 3% of adults are obese
- 4% have severe obesity (BMI ≥40)
Obesity contributes to:
- Chronic inflammation
- Immune system impairment
- Increased risk for Type 2 diabetes, cardiovascular disease, stroke, and certain cancers
Conclusion: BMI 50 is a Turning Point for Surgical Risk
This new information marks a critical turning point at BMI 50, where post-operative complications from bariatric surgery risk is elevated. Although the procedures continue to be safe in the majority, special care and pre-op planning are needed for patients with extremely high BMI.
These findings are the foundation of targeted risk assessment and enhanced counselling, enabling both physicians and patients to make safer, more informed decisions.
Inputs from various media sources.
Dane
I am an MBBS graduate and a dedicated medical writer with a strong passion for deep research and psychology. I enjoy breaking down complex medical topics into engaging, easy-to-understand content, aiming to educate and inspire readers by exploring the fascinating connection between health, science, and the human mind.
