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.