Are we operating too late?  Mortality Analysis and Stochastic Simulation of Costs Associated with Bariatric Surgery: Reconsidering the BMI Threshold

Background: Present guidelines recommend bariatric surgery at BMI ≥40 kg/m² or BMI ≥35 kg/m² with obesity-related morbidity. Methods: Evidence for cost and mortality/morbidity risk of bariatric surgery and obesity-related diseases was evaluated determining equivalency point of absolute incremental mortality risk by BMI and risks associated with bariatric surgery. A stochastic model was developed evaluating costs related to surgical procedure at a given BMI. Results: Bariatric surgery produces significant lifetime cost savings associated with diabetes, gallstones, hypertension, high cholesterol, colon cancer, heart disease, and stroke in men at BMI 30 kg/m² for laparoscopic gastric bypass. For women, laparoscopic gastric bypass saves cost at BMI 32 kg/m² and laparoscopic gastric banding at BMI 37 kg/m². In white men, relative to single-year mortality risks by BMI, surgical intervention becomes risk-beneficial at BMI 25 kg/m² for laparoscopic gastric banding, BMI 27 kg/m² for laparoscopic gastric bypass procedure and open gastric banding, and BMI 37 kg/m² for open gastric bypass. Risk benefit for African-American men by procedure occurs at BMI <25 kg/m², BMI 27 kg/m², and BMI 42 kg/m², respectively. In white women, surgical intervention is beneficial at BMI 25.5 kg/m² (laparoscopic gastric banding), BMI 28.5 kg/m² (laparoscopic gastric bypass procedure), and BMI 45 kg/m² (open gastric banding). Risk benefit for black women by procedure occurs at BMI 27.5 kg/m², BMI 33.5 kg/m², and BMI 50+ kg/m², respectively. Conclusion: Risk and cost benefit suggest surgical guidelines should be reconsidered. Threshold for bariatric surgery should be redefined to BMI 35 kg/m² or BMI 30 kg/m² with comorbidities.