Preoperative prognostic nutritional index predicts postoperative delirium in elderly patients after hip fracture surgery.

BACKGROUND

Postoperative delirium (POD) is a very common complication in elderly patients after hip fracture surgery, which has poorly understood pathophysiology. This study aimed to investigate potential risk factors for POD.

METHODS

Elderly patients (aged ≥65 years) scheduled to undergo selective surgery in our hospital were consecutively recruited. Patient characteristics, preoperative laboratory tests and prognostic nutritional index (PNI) levels were compared between patients with or without POD. The risk factors for POD were evaluated by univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive value of PNI and age for POD.

RESULTS

Fifty-seven of the 163 enrolled patient had suffered POD within postoperative day 7 with an incidence of 35.0%. Multivariate logistic analyses revealed that an advanced age (cut-off value: 71.5 years, sensitivity: 48.1%, specificity: 75.4%, odds ratio (OR): 3.24, 95% CI: 1.16-8.69, P = 0.026) and lower PNI level (cut-off value: 47.45, sensitivity: 86.0%, specificity: 51.9%, OR: 2.88, 95% CI: 1.25-6.64, P = 0.012) were two independent predictive factors associated with POD. According to the ROC curve analysis, preoperative PNI level was a predictor for POD with an area under the curve of 0.686 (95% CI: 0.604-0.767, P < 0.001).

CONCLUSIONS

Advanced age and lower preoperative PNI level were significantly associated with POD in elderly patients after hip fracture surgery.