Association Between Preoperative Malnutrition and Postoperative Delirium After Hip Fracture Surgery in Older Adults

Abstract

Objectives: To determine whether poor nutritional status can predict postoperative delirium in elderly adults undergoing hip fracture surgery.

Design: Prospective observational cohort study.

Setting: Italian orthogeriatric unit.

Participants: Individuals aged 70 and older (mean age 84.0 ± 6.6, 74.5% female) consecutively admitted for surgical repair of a proximal femur fracture between September 2012 and April 2016 (N = 415).

Measurements: Participants underwent a comprehensive geriatric assessment including nutritional status, which was evaluated using the Mini Nutritional Assessment Short Form (MNA-SF). The MNA-SF-based three-class stratification was tested using multivariable logistic regression to assess its role in predicting postoperative delirium (outcome).

Results: Seventy-eight malnourished individuals (MNA-SF score 0-7), 185 at risk of malnutrition (MNA-SF score 8-11), and 152 who were well nourished (MNA-SF score 12-14) were compared. On average, individuals with poor nutritional status were more disabled and more cognitively impaired than those who were well nourished and those at risk of malnutrition. Moreover, those who were malnourished were more likely to have postoperative delirium. Multivariate regression analysis adjusted for age, sex, comorbidity, functional impairment, preoperative cognitive status, and American Society of Anesthesiologists score showed that those who were at risk of malnutrition (odds ratio (OR) = 2.42, 95% confidence interval (CI) = 1.29-4.53) and those who were overtly malnourished (OR = 2.98, 95% CI = 1.43-6.19) were more likely to develop postoperative delirium.

Conclusion: This is the first study in a Western population showing that risk of malnutrition and overt malnutrition, as assessed using the MNA-SF, are independent predictors of postoperative delirium. Accordingly, nutritional status should be assessed in individuals with hip fracture before surgery to determine risk of developing delirium.

Keywords: Mini-Nutritional Assessment Short Form; elderly; hip fracture; malnutrition; postoperative delirium.

Conflict of interest statement

Conflict of Interest: The authors declare that the present manuscript was unfunded and that they have no conflicts of interest to disclose in relation to its preparation. Data collection and all the analyses comply with the current Italian laws and the ethical committee of the University of Milano-Bicocca. All individuals included in the database (or their legal proxies) gave permission to receive hospital treatments, for recording of personal healthcare information, and for the use of these data for research purposes. All written consent forms are stored in the archive of San Gerardo Hospital ASST Monza. Data have been de-identified and protected, in line with the privacy policy of ASST Monza and University of Milano-Bicocca. This prospective study was conducted according to the Helsinki II Declaration.

© 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

Figures

Figure 1.

Flow chart for identification of study cohort among individuals consecutively hospitalized between September 2012 and April 2016.