Medical therapies and invasive treatments for coronary artery disease by body mass: the "obesity paradox" in the Get With The Guidelines database

Abstract

Previous studies of hospitalized patients have suggested an "obesity paradox" with lower short-term mortality as weight increases. We hypothesized that some of this difference might be related to more aggressive management. To evaluate the effect of body mass index (BMI) on treatments and outcomes in patients with coronary artery disease (CAD), the Get With The Guidelines database was investigated. From 409 United States hospitals, 130,139 hospitalizations for CAD were identified with documented height and weight. Patients were stratified by BMI, with 3,305 (2.5%) underweight (BMI <18.5 kg/m(2)), 34,697 (27%) of healthy weight (BMI 18.5 to 24.9 kg/m(2)), 47,883 (37%) overweight (BMI 25 to 29.9 kg/m(2)), 37,686 (29%) obese (BMI 30 to 39.9 kg/m(2)), and 6,568 (5%) extremely obese (BMI > or =40 kg/m(2)). As BMI increased, patients were significantly younger but more likely to be men and have hypertension, diabetes, and hyperlipidemia. Unadjusted in-hospital mortality was highest in the underweight group (10.4%) and significantly lower in the healthy-weight (5.4%), overweight (3.1%), obese (2.4%), and extremely obese (2.9%) patients. Higher BMI was associated with increased use of standard medical therapies such as aspirin, beta blockers, inhibitors of the renin-angiotensin system, and lipid-lowering therapy in the hospital and at discharge. In adjusted analyses, compared with the healthy-weight group, overweight and obese patients were more likely to undergo invasive procedures and had lower mortality (p <0.01 for all odds ratios). In conclusion, increasing BMI appears to be associated with better use of guideline-recommended medical treatment and invasive management of CAD, which may explain the observed lower rates of in-hospital mortality.