Malnutrition is not related with emergence delirium in older patients after noncardiac surgery

BACKGROUND: Delirium is one of the most common complications in older surgical patients. Although previous studies reported that preoperative malnutrition was related with postoperative delirium (POD), there was lack of evidence to illustrate the relationship between malnutrition and emergency delirium (ED). The objective of this study was to investigate the relationship between preoperative malnutrition and ED in older patients undergoing noncardiac surgery. METHODS: The study was carried out in accordance with STROBE guidelines. This was a secondary analysis of a prospective cohort study. Older patients (65–90 years) who underwent noncardiac surgery under general anesthesia were enrolled in Peking University First Hospital. RESULTS: 915 patients were enrolled. The incidence of malnutrition was 53.6 % (490/915). The incidence of emergency delirium was 41.8 % (205/490) in malnutrition group and 31.5 % (134/425) in control group, P < 0.001. After adjusting confounding factors (i.e., age, cognitive impairment, American Society of Anesthesiologists classification (ASA), duration of surgery, pain score, low body temperature and allogeneic blood transfusion), malnutrition was not associated with increased risk of emergency delirium (OR = 1.055, 95 % CI 0.767–1.452, P = 0.742). CONCLUSIONS: Malnutrition was common in older patients undergoing non-cardiac surgery, but it’s not related with emergence delirium after adjusted for confounders. TRIAL REGISTRATION: Chinese Clinical Trial Registry (http://www.chictr.org.cn) (ChiCTR-OOC-17,012,734). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-021-02270-2.