Association Between Body Mass Index and Mortality in Patients Requiring Cardiac Critical Care

Background: Data on the association between obesity and mortality in patients who require acute cardiac care are limited, so we investigated the effect of obesity on clinical outcomes in patients admitted to the cardiac intensive care unit (CICU). Methods and Results: We reviewed 2,429 eligible patients admitted to the CICU at Samsung Medical Center between January 2012 and December 2015. After excluding 197 patients with low body mass index (BMI) to adjust for the possibility of frailty, patients were divided into 3 categories: normal BMI (n=822), 18.5-22.9 kg/m(2); moderate BMI (n=1,050), 23-27.4 kg/m(2); and high BMI (n=360), >= 27.5 kg/m(2). The primary outcome was 28-day mortality. Overall, 124 (2.6%) of 2,232 patients died during 28-day follow-up after CICU admission. The 28-day mortality was numerically lower in the moderate (4.5%) and high (5.3%) BMI groups than in the normal BMI group (7.1%), but the difference was not statistically significant (P=0.052). After multivariable adjustment, the moderate and high BMI categories were not significant predictors of primary outcome (adjusted hazard ratio [HR] 0.74, 95% CI 0.50-1.09, P=0.127 and adjusted HR 0.80, 95% CI 0.47-1.36, P=0.404, respectively). However, Acute Physiology and Chronic Health Evaluation II scores, liver cirrhosis, malignancy, history of cardiac arrest, and need for organ support treatment were independent predictors of 28-day mortality. Conclusions: Obesity was not associated with short-term mortality in patients requiring cardiac critical care.