Computer Model Estimates Benefits of Bariatric Surgery for Severely Obese

A computerized model suggests that most morbidly obese individuals would likely live longer if they had gastric bypass surgery, according to a new study.

Researchers at the University of Cincinnati Academic Health Center (OH, USA) used two U.S. nationally representative surveys and a large observational trial to construct a model estimating the benefits and risks of gastric bypass surgery for individuals with morbid obesity. The model included data from almost 400,000 individuals to estimate the risk of death from obesity and its complications; further data from 23,281 patients undergoing bariatric surgery to calculate in-hospital death rates following the procedures; and outcomes from participants in a seven-year study to determine the effects of surgery on survival and to calibrate and validate the model.

According to the resulting model, an average 42-year-old woman with a body mass index (BMI) of 45 would gain an estimated additional three years of life expectancy as a result of undergoing bariatric surgery; a 44-year-old man with the same BMI would gain an estimated 2.6 additional years. Additional analyses revealed that younger women with higher BMIs are projected to gain the most life expectancy from surgery. Younger men with higher BMIs might also gain more life expectancy after surgery, but the gain would be less for men than for women in each subgroup. The study was published in the January 2010 issue of Archives of Surgery.

"While not all patients are guaranteed a good outcome, our model indicates that gastric bypass increases life expectancy for most patient subgroups; however, for those at high surgical risk or in whom efficacy of surgery is likely to be low, benefit will be minimal,” concluded lead author assistant professor Daniel Schauer, M.D., M.Sc., and colleagues of the department of clinical medicine outcomes. "We believe results of this analysis can be used to better inform both patients' and physicians' decisions regarding gastric bypass surgery.”

An estimated 5.1% of the U.S. population is morbidly obese, often defined as having a body mass index (BMI) of 40 or higher. Dietary, behavioral, and pharmacologic treatments frequently do not result in meaningful weight loss for individuals in this group, and bariatric surgery appears to be the only effective therapy for promoting clinically significant weight loss and improving obesity-related health conditions for the morbidly obese.

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