The Underestimated Belly Factor: Waist Circumference Is Linked to Significant Morbidity Following Isolated Coronary Artery Bypass Grafting

Background: Waist circumference (WC) and body mass index (BMI) are clinically used to assess adiposity. The aim of the present study was to evaluate the association of WC with postoperative morbidity and mortality in patients who underwent isolated coronary artery bypass grafting (CABG) in relation to patients' BMI category. Methods: We analyzed the associations of WC and BMI with short-term postoperative outcomes in a cohort of 7446 patients who underwent isolated CABG. We performed univariate and adjusted analyses on main postoperative outcomes after CABG for WC and BMI. Results: Adverse events researched included postoperative mortality, intensive care unit and hospital length of stay, cardiovascular and cerebrovascular events, respiratory complications, infectious, hemostasis complications, and renal complications. WC was independently associated with all postoperative outcomes except prolonged intubation and mortality. Overall, patients in the upper WC quartile in each BMI category were at increased risk of adverse events compared with patients in the lower 3 WC quartiles, with a maximal incremental risk of 1.91 (95% confidence interval, 1.23-2.95) among patients with a BMI >= 35. This association was observed for men and women, across all overweight and obesity categories. Neither WC nor BMI was associated with short-term postoperative mortality. Conclusions: In our large cohort of patients who underwent isolated CABG, WC was significantly associated with clinical adverse events, independently of BMI. These findings provide further evidence on the added value of measuring WC as a simple and easy to measure anthropometric marker to refine risk assessment beyond BMI among patients who undergo CABG.