Malnutrition in cardiac surgery: food for thought

Undernourished patients treated in general surgery departments suffer from prolonged and complicated hospitalizations, and higher mortality rates compared with well nourished patients. Pivotal information regarding patients' nutritional status and its effect on clinical outcome is lacking for cardiac surgery patients. We investigated the prevalence of malnutrition risk and its association with 30-day hospital mortality and postoperative complications.

Four hundred and three patients who underwent cardiac surgery during 2008 and were screened with the Malnutrition Universal Screening Tool (MUST) on admission were enrolled. Univariate and multivariate logistic regression analyses compared the association of high and low risk for malnutrition with length of hospitalization (LOS), in-hospital and 30-day mortality, and postoperative complications. Almost 20% of the patients were found to be at high risk for malnutrition. Univariate analyses revealed higher in-hospital mortality rates (p = 0.03) and greater incidence of LOS and antibiotic treatment longer than 21 days (p = 0.002 and p = 0.04, respectively), vasopressor treatment longer than 11 days (p = 0.02), and positive blood cultures (p = 0.02) in patients belonging to the high-risk MUST group. Incorporation of the MUST in a multivariate model with the European System for Cardiac Operative Risk Evaluation (EuroSCORE) significantly improved postoperative complications prediction, as well as in-hospital and 30-day mortality, compared with the EuroSCORE alone.

Malnutrition is prevalent in patients undergoing cardiac surgery, associated with higher postoperative mortality and morbidity. Preoperative MUST screening has emerged as highly relevant for enabling early diagnosis of patients at malnutrition risk, predicting postoperative mortality and morbidity, thus promoting well timed treatment. Prospective studies are needed to explore whether intervention can decrease malnutrition risk.