Combining Body Mass Index With Measures of Central Obesity in the Assessment of Mortality in Subjects With Coronary Disease: Role of “Normal Weight Central Obesity”

ObjectivesThis study sought to assess the mortality risk of patients with coronary artery disease (CAD) based on a combination of body mass index (BMI) and measures of central obesity.BackgroundIn CAD patients, mortality has been reported to vary inversely with BMI (“obesity paradox”). In contrast, central obesity is directly associated with mortality. Because of this bi-directional relationship, we hypothesized that CAD patients with normal BMI but with central obesity would have worse survival compared with subjects with other combinations of BMI and central adiposity.MethodsWe included 15,547 participants with CAD who took part in 5 studies from 3 continents. Multivariate stratified Cox-proportional hazard models that adjusted for potential confounders were used to assess mortality risk according to different patterns of adiposity that combined BMI with measures of central obesity.ResultsMean age was 66 years; 55% were men. There were 4,699 deaths over a median follow-up of 4.7 years. Subjects with normal weight but central obesity had the worst long-term survival: a person with BMI of 22 kg/m2 and waist-to-hip ratio (WHR) of 0.98 had higher mortality than a person with similar BMI but WHR of 0.89 (hazard ratio [HR]: 1.10; 95% confidence interval [CI]: 1.05 to 1.17); than a person with BMI of 26 kg/m2 and WHR of 0.89 (HR: 1.20; 95% CI: 1.09 to 1.31), than in a person with BMI of 30 kg/m2 and WHR of 0.89 (HR: 1.61; 95% CI: 1.39 to 1.86), and than a person with BMI of 30 kg/m2 and WHR of 0.98 (HR: 1.27; 95% CI: 1.18 to 1.39) (p < 0.0001 for all).ConclusionsIn patients with CAD, normal weight with central obesity was associated with the highest risk of mortality.