Preoperative unintended weight loss and low body mass index in relation to complications and length of stay after cardiac surgery

BACKGROUND: Several studies reported increased adverse outcomes after cardiac surgery in patients with low body mass index (BMI; in kg/m(2)). Little is known yet, however, about the effect of preoperative unintended weight loss (UWL) in cardiac surgery patients. OBJECTIVE: We explored the prevalence and effect of UWL in view of low BMI and vice versa adjusted for a validated set of preoperative risks, inflammatory activity, and duration of extracorporeal circulation on postoperative adverse outcome. DESIGN: A prospective cohort study was performed. Nutritional data of cardiac surgery patients were collected within 24 h of admission and linked to the standard postoperative complication registration database. RESULTS: The cohort consisted of 331 cases. Multivariate logistic regression analyses showed that preoperative UWL of >or=10% in the past 6 mo (>or=10%UWLin6m) was associated with a prolonged length of stay in the hospital independent from low BMI [odds ratio (OR): 7.06; 95% CI: 1.78, 28.04]. Preoperative BMI <or= 21.0 was associated with an increased incidence of postoperative infections and prolonged stay in the intensive care unit independent from >or=10%UWLin6m (OR: 4.62; 95% CI: 1.20, 17.82; and OR: 5.27; 95% CI: 1.28, 21.76, respectively). Preoperative undernutrition in cardiac surgery patients (>or=10%UWLin6m or BMI <or= 21.0 or both) was present in 9.1% of the study population (4.3% and 4.8%, respectively). CONCLUSIONS: From this study, we recommend special attention for cardiac surgery patients with preoperative >or=10%UWLin6m or BMI <or= 21.0 because both variables are independently related to adverse outcomes. Preoperative referral to a dietitian for further diagnostic assessment and nutritional treatment is strongly recommended