Body mass index and albumin in the preoperative evaluation of cardiac surgery patients

Background & aims: An increasing proportion of cardiac surgery is performed in the elderly where nutritional status is an important predictor of outcome. Our aim was to evaluate serum albumin concentration (S-albumin) and body mass index (BMI) as markers of malnutrition in relation to outcome measured as mortality and frequency of infections. Patients & methods: We studied 886 consecutive patients who underwent cardiac surgery with extra-corporeal circulation for valve procedures, coronary artery bypass grafting or a combination of those. Preoperative assessment included age, gender, BMI, smoking habits, diabetes, left-ventricular function, S-albumin and C-reactive protein. Postoperative data was type of surgery, in-hospital stay, signs of infections and mortality. Risk factors for mortality were identified using the Cox proportional hazard model and risk factors for infections by using the logistic-regression model. Results: The patients (age 67±9.5 years) were followed for 22±6 months. In an univariate analysis low BMI and low S-albumin increased relative hazard for death and risk for infection. In a multivariate analysis low BMI, but not S-albumin, increased relative hazard for death and low S-albumin, but not BMI, increased risk for infection. Age, diabetes and longer bypass time increased the risk for infection. Conclusion: In cardiac surgery patients a low BMI increased the relative hazard for death and low S-albumin increased the risk for infection. We suggest that these parameters provide useful information in the preoperative evaluation.