BackgroundThe European Society for Clinical Nutrition and Metabolism recommends nutrition screening using the Mini Nutritional Assessment Short-Form (MNA-SF) in older adult patients preoperatively. However, the association of nutrition condition with postoperative complications is poorly documented. We aimed to identify preoperative nutrition status using the MNA-SF and to determine whether preoperative nutrition status affects postoperative outcomes. MethodsInpatients aged >= 55 years who underwent elective abdominal surgery under general anesthesia between April 1, 2016, and December 28, 2018, were included. We assessed nutrition status using the MNA-SF before surgery. Multiple logistic regression including the MNA-SF score was applied to determine associated factors with our primary outcome, postoperative complications defined as Clavien-Dindo classification >= 3a. Secondary outcomes including length of hospital stay and unplanned readmission were compared between normal, at risk, and malnourished patients. ResultsThe data of 1248 patients with a mean age of 69 years were analyzed. The prevalence of at risk and malnutrition was 33.0% (412 of 1248) and 6.9% (87 of 1248), respectively. Overall, 12.4% (155 of 1248) had major postoperative complications, and the MNA-SF score was a significant predictor (odds ratio: 0.92, 95% CI: 0.86-0.99) after adjusting for confounders. Patients at risk of malnutrition and those with malnutrition had a longer hospital length of postoperative stay than normal patients (P = 0.001); however, there was no statistical significance in unplanned readmission rate between the three groups (P = 0.14). ConclusionPreoperative nutrition disorder was common, and it affected postoperative adverse outcomes. The MNA-SF score was associated with major postoperative complications.