Influence of body mass index on extent of coronary atherosclerosis and cardiac events in a cohort of patients at risk of coronary artery disease

BACKGROUND AND AIM: To estimate if a meaningful relationship exists between body mass index (BMI) and the entity of coronary atherosclerosis, coronary events and mortality in a cohort of consecutive patients with suspected coronary artery disease (CAD).METHODS AND RESULTS: In this prospective study, we enrolled 1299 consecutive patients (905 [69.7%] males) who had undergone coronary angiography. Our sample consisted of 477 patients (36.8%) of normal weight; 567 (43.6%) overweight and 255 (19.6%) obese, according to the WHO classification. Conventional cardiovascular risk factors, BMI, endothelial function and subclinical inflammation were studied. Different angiographic CAD scores were used to quantify coronary atherosclerotic burden. In overweight and obese patients, respect to normal weight population, there is a higher prevalence of hypertension, hypercholesterolemia and diabetes mellitus, but BMI was not significantly associated with greater extent of coronary atherosclerosis. At follow-up (mean: 40; range: 24-82 months) obese and overweight patients showed a higher incidence of coronary events compared to the normal weight population (74.9% [obese] versus 62.7% [overweight] versus 53.2% [normal weight]; adjusted relative risk [obese versus overweight]: 1.08 [95% confidence interval: 1.02-1.23]; P<0.05; and adjusted RR [obese versus normal weight]: 1.17 [95% CI: 1.10-1.42], P<0.01). Mortality from cardiac events was not significant within the categories. The Cox regression model showed flow mediated dilation (P<0.0001), high-sensitive C reactive protein (P=0.022) and BMI (P=0.045) as independent predictors of acute coronary events.CONCLUSION: BMI is not associated with the extent of coronary atherosclerosis and mortality. The higher incidence of coronary events in obese subjects is only partly explained by conventional associated risk factors. Impaired endothelial function and sub-clinical inflammation could be involved in this association but BMI itself is related to cardiovascular events suggesting that other unknown (or not considered) pathways are involved.