Association between body mass index and outcome of coronary artery bypass

Studies have shown disparate findings regarding body mass index and outcomes after coronary artery bypass. We analyzed body mass index and other clinical variables that might predict morbidity and mortality after primary isolated coronary artery bypass. Data on 4,425 patients (79% men) were reviewed retrospectively. They were classified as underweight (1.6%), normal weight (65%), obese (32%), and morbidly obese (1.4%) according to body mass index < 20, 20–29, 30–39, and > 40 kgċm⁻², respectively. Multiple logistic regression was used for correlates of 30-day outcome. Cox regression was used for predictors of late outcome in underweight and morbidly obese patients. There were 45 (1%) deaths and 234 (5%) cases of morbidity within 30 days. Independent correlates of 30-day morbidity were smoking, logistic EuroSCORE, blood and blood product transfusions. Correlates of 30-day mortality were logistic EuroSCORE and blood transfusion. The only independent predictor of late death in underweight and morbidly obese patients was preoperative arrhythmia. Body mass index was not a predictor of 30-day morbidity or mortality. The 1-, 3-, and 7-year survival rates were not significantly different between underweight and morbidly obese patients. Body mass index did not affect short-term outcomes after primary coronary artery bypass grafting.