f Gastric on, MD, MPH,

than 6-fold, with more than 82 000 procedures in 34 ease in the use of bariatric d by a combination of fac-usion of minimally invasive surgical techniques, increased cultural sensitivity, awareness through increased growth nefits associated with gastric patients. Although the use of gastric bypass is growing rapidly, the potential life expectancy benefits of the procedure are unknown. We created a Markov decision analysis model to examine the effect of gastric bypass surgery on life expectancy in morbidly obese patients (body mass index [BMI] = 40 kg/m2). Input assump-tions for the model were obtained from published life tables (baseline mortality risks), epidemiologic studies (obesity-related excess mortality), and large case series (surgical outcomes). In our baseline analysis, a 40-year-old woman (BMI = 40 kg/m2) would gain 2.6 years of life expectancy by undergoing gastric bypass (38.7 years versus 36.2 years without surgery). In sensitivity analysis, life-years gained with surgery remained sub-stantial when assumptions were varied across reason-able ranges for surgical mortality risk (1.0-3.0 years) and effectiveness (0.9-4.4 years). Life-years gained with gastric bypass surgery did not vary considerably by age and sex subgroups. Relative to other major surgical procedures, gastric bypass for morbid obesity is associ-ated with substantial gains in life expectancy. Long-term data from prospective studies are needed to confirm this finding