The association between preoperative nutritional status and postoperative delirium in individuals with coronary artery bypass graft surgery: A Prospective Cohort Study

Abstract Objectives The prevalence of delirium and undernutrition are both relatively high in post-coronary artery bypass graft (CABG) surgery. We evaluated the association between preoperative malnutrition with the occurrence of delirium after CABG surgery. Methods In this prospective cohort study, body mass index (BMI), mid-upper arm circumference, triceps skinfold and adductor pollicis muscle thickness were measured by a single trained dietitian on 398 adult patients before CABG surgery. Also, Nutritional Risk Screening 2002 (NRS-2002) and Subjective Global Assessment (SGA) were obtained from patients. Delirium was defined by the confusion assessment method for the intensive care unit. SPSS software was used for performing the statistical analyses. Logistic regression analysis was applied to examine the impact of various factors on the development of delirium. Results Postoperative delirium was detected in 17% (n=68) of patients. Multivariate regression analysis adjusted by other risk factors indicated that risk of delirium was 1.56 fold higher in patients with NRS-2002>3 (OR = 1.56; 95% CI: 1.20-3.24; P= 0.001). Admission severe under-nutrition assessed by SGA was independently associated with the occurrence of delirium (OR = 2.58; 95% CI: 1.02-3.48; P= 0.005). Risk of delirium was 1.26 fold higher in patients with Adductor pollicis muscle thickness lower than 15 millimeter (OR = 1.26; 95% CI: 1.02-3.14; P= 0.02). Conclusions Since the prevalence of delirium is relatively high in CABG surgery and undernutrition is related to post-operative delirium, considering nutrition status with NRS-2002, SGA or adductor pollicis muscle thickness before surgery could decrease the risk of post-operative delirium.