Relation between obesity and severity of coronary artery disease in patients undergoing coronary angiography.

We examined the relations among body mass index (BMI), extent of coronary artery disease, and frequency of high-risk coronary anatomy (HRCA) in 928 consecutive patients who underwent coronary angiography during a 6-month period. HRCA was defined as >or=50% stenosis of the left main coronary artery and/or significant 3-vessel coronary artery disease (>or=70% narrowing). BMI was classified into 5 subgroups: low (<21 kg/m(2)), normal (21 to 24 kg/m(2)), overweight (25 to 29 kg/m(2)), obese (30 to 34 kg/m(2)), and severely obese (>or=35 kg/m(2)). Obese patients (BMI >or=30 kg/m(2)) were younger (61.4 +/- 10.7 vs 65.3 +/- 11.4 years, p <0.0001) and had higher prevalences of hyperlipidemia, systemic hypertension, and diabetes mellitus. HRCA was present less often in obese patients (56 of 245, 23%, vs 250 of 683, 37%, p = 0.0002). Multivariate regression analysis showed that advancing age (p <0.0001), male gender (p = 0.007), diabetes mellitus (p = 0.0004), and hyperlipidemia (p = 0.0008) were independent predictors of high-risk anatomy, whereas obesity remained a significant negative independent predictor (p = 0.02). Late (30 to 36 months) mortality was not different between obese (6.9%) and nonobese (8.2%) patients but was significantly higher in patients with HRCA (12.4%) than in those without HRCA (5.6%, p = 0.0003). In conclusion, obese patients who were referred for coronary angiography were younger and had a lower prevalence of HRCA. Obese patients were probably referred for angiography at an earlier stage of their disease, thus explaining the "obesity paradox" in several reports of better short-term outcome in obese patients who undergo cardiac procedures.