Body Mass Index Not Major Predictor of Death in Bariatric Surgery Eligibility

Age, sex, smoking and diabetes mellitus can be used to estimate 10-year mortality for obese patients eligible for bariatric weight-loss surgery, while body mass index (BMI) was not a predictor of mortality, according to a study by Raj S. Padwal, M.D., M.Sc., of the University of Alberta, Canada, and colleagues.

BMI is a primary eligibility criterion for bariatric surgery, based on evidence that higher BMIs are associated with worse outcomes. These researchers devised a prediction rule for 10-year mortality from all causes in patients eligible for bariatric surgery based on BMI, age, type 2 diabetes mellitus and sex.

The study included 15,394 obese patients (ages 18 to 65 years) with an average BMI of 36.2 from the United Kingdom General Practice Research Database.

The all-cause mortality rate was 2.1 percent. Age and type 2 diabetes were the strongest risk factors for mortality, while BMI was the weakest, according to the study results.

“In conclusion, our findings demonstrate that factors other than BMI are important in predicting the risk of death in patients eligible for bariatric surgery and that, of the obesity-related comorbidities, type 2 diabetes mellitus is the most important morality predictor. Given that diabetes mellitus is highly amenable to surgical treatment, a strong case could be made for prioritizing it over BMI or other comorbidities,” for determining eligibility for bariatric surgery, the study concludes.

JAMA Surgery. Published online October 16, 2013. doi:10.1001/jamasurg.2013.3953.