INVESTIGATING HOW BODY MASS INDEX INFLUENCES SURGICAL SUCCESS AND COMPLICATIONS: A SYSTEMATIC REVIEW

Abstract

Background: Body mass index (BMI) is a key determinant of perioperative risk. Both extremes—underweight and obesity—have been linked to adverse surgical outcomes, while moderate overweight may exhibit protective effects (“obesity paradox”). This review systematically evaluates BMI’s influence on postoperative complications and surgical success across general, gastrointestinal, hepatobiliary, orthopedic, cardiac, and obstetric procedures.

Methods: A systematic review was conducted following PRISMA 2020 guidelines. Peer-reviewed studies published between 2010–2025 were retrieved from PubMed, Scopus, Web of Science, Embase, and Google Scholar. Eligible studies included adult surgical patients, reported BMI categories, and assessed postoperative complications, mortality, readmission, or procedure-specific outcomes. Data extraction included study design, sample size, surgical type, BMI classification, effect estimates, and follow-up duration. Quality was appraised using Newcastle–Ottawa Scale and Cochrane RoB 2 tools.

Results: Fifteen studies comprising 84 to 153,429 patients were included. Findings revealed a consistent U-shaped association between BMI and postoperative complications. Obese patients demonstrated higher rates of wound infections, mechanical failures, and cardiopulmonary complications, while underweight individuals showed elevated mortality and delayed healing. Moderate overweight occasionally conferred neutral or slightly improved outcomes, reflecting the obesity paradox. Variations were noted across specialties: orthopedic and hepatobiliary procedures exhibited strong BMI-related morbidity, spine surgery showed minimal short-term impact, and obstetric outcomes mirrored non-obstetric patterns with elevated risk in both low and high BMI.

Conclusion: BMI significantly influences surgical outcomes, with extremes increasing perioperative risk. Individualized risk assessment, nutritional optimization, and targeted preoperative interventions are recommended to mitigate BMI-related complications.