Severity of coronary artery disease in obese patients undergoing coronary angiography: "Obesity paradox" revisited

Background: Recent studies have highlighted the existence of an 'obesity paradox' in patients undergoing coronary angiography, i.e., a high body mass Index (BMI) is associated with less severe coronary lesions. We sought to confirm the existence of this phenomenon in the US patient population. Methods: Study subjects included 770 consecutive patients (470 men, 428 African-Americans, 212 Caucasians) referred for coronary angiography to a tertiary care center. Duke myocardial jeopardy score, a prognostication tool predictive of I-year mortality in coronary artery disease (CAD) patients, was assigned to angiographic data. Patients were classified according to their BMI (kg/m(2)) as normal (21-24), overweight (25-29), obesity class 1 (30-34), class II (35-39) and class III (40 or above). Results: Patients in the increasing obesity class had a higher prevalence of diabetes, hypertension and dyslipidemia and were more likely to be women. A negative correlation was observed between BMI and age (R = -0.15 p < 0.001) as well as between BMI and Duke Jeopardy score (r = -0.07, p < 0.05) indicating that patients with higher BMI were referred for coronary angiography at a younger age, and had a lower coronary artery disease (CAD) burden. BMI was not an independent predictor of coronary lesion severity on multivariate stepwise linear regression analysis. Conclusion: Obese patients are referred for coronary angiography at an earlier age and have a lower CAD burden lending further credence to the existence of an apparent "obesity paradox". However, obesity per se, after adjustment for comorbidities, is not an independent predictor of severity of coronary artery disease.