Short-Form Mini Nutritional Assessment as a useful method of predicting the development of postoperative delirium in elderly patients undergoing orthopedic surgery.

Objective: Postoperative delirium (POD) is a major cause for concern among elderly patients undergoing surgery, often resulting in poor outcome. It is therefore important to predict and prevent POD. The aim of this study was to evaluate the Mini Nutritional Assessment Short-Form (MNA-SF) as a predictor of POD after orthopedic surgery.

Methods: Elderly patients undergoing orthopedic surgery between April 2011 and March 2013 were included in the study (n=544; mean age, 74.24 ± 7.92 years). The MNA-SF was used to evaluate preoperative nutritional status. Delirium was assessed daily after surgery using the confusion assessment method. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria were used to confirm delirium diagnosis. Univariate and multivariate logistic regression analyses were performed to identify key factors associated with POD.

Results: POD occurred in 52 patients (9.6%). According to the MNA-SF, 17.5% of subjects were at risk of undernutrition. Adjusting for all potential factors in the final model, age, male gender and lower Mini-Mental State Examination and higher Charlson Comorbidity Index scores were associated with significantly increased likelihood of POD. Subjects who were identified preoperatively as at risk of undernutrition were 2.85 times more likely to develop POD compared to normally nourished subjects (odds ratio: 2.85, 95% confidence interval: 1.19-6.87).

Conclusions: These results suggest that the MNA-SF is a simple and effective tool that can be used to predict incident delirium in elderly patients after orthopedic surgery.