Low incidence of delirium in very old patients after surgery for hip fractures.

OBJECTIVE: The authors sought to determine the incidence of delirium, its predisposing and precipitating factors, and its implications for rehabilitation outcomes and mortality in elderly patients.
METHODS: This was a prospective cohort study, conducted in Gedera, Israel, from August 2001 to January 2002, with 137 consecutive patients over age 75, with hip fractures, who were admitted to the orthopedic section of the emergency department. They were evaluated at admission, 1 week after the surgery for hip fracture, and 1 month after surgery. The evaluation included assessments of delirium, cognitive, and functional status, and a wide range of demographic and clinical parameters.
RESULTS: The cumulative incidence of delirium was 11.4%. No significant difference was found between delirium and non-delirium patients in terms of all demographic, socioeconomic, and perioperative parameters. Mild or moderate cognitive impairment before the fracture and four or more regular medications prescribed to the patient were the only predictive factors for the development of delirium in a multivariate model. Delirium was not a significant predictor of any rehabilitation outcome.
CONCLUSION: Results documented that the incidence of delirium after hip fracture in elderly patients is much lower than was reported in several previous studies. Premorbid cognitive impairment was the most significant predisposing factor for the development of delirium. Thorough evaluation of earlier cognitive status could improve the probability of the diagnosis of delirium and pinpoint a limited group of patients for a delirium-prevention approach.