Frequency, risk factors, and prognosis of prolonged delirium in elderly patients after hip fracture surgery

Abstract

Background: Delirium in elderly patients after hip fracture surgery is believed to be a transient event, although it frequently lasts for more than 4 weeks.

Questions/purposes: We determined the incidence, risk factors, morbidity, and mortality of prolonged delirium in elderly patients after hip fracture surgery.

Patients and methods: We evaluated 232 elderly patients (older than 65 years) (232 hips) who underwent hip fracture surgery for the development and duration of delirium and categorized them into three groups; nondelirium group, transient (≤ 4 weeks) delirium group, and prolonged (> 4 weeks) delirium group. Patients underwent a global geriatric evaluation, which included postoperative complications, mortality, and functional and mental status evaluations. The three groups were compared with respect to these variables.

Results: Seventy patients (30.2%) had delirium develop, and among these, 14 (20%) had prolonged delirium with a total incidence of 6%. Multivariate analysis showed preinjury dementia was a risk factor of prolonged delirium. At the final followup, five (62.5%) of the eight patients who were ambulatory outdoors in the prolonged delirium group became housebound, whereas only 18 (16.4%) of the 110 patients who were ambulatory outdoors in the nondelirium group became housebound. Survival at 40 months was 81.0% (95% confidence interval, 72.6%-89.3%) in the nondelirium group and 63.6% (95% confidence interval, 35.2%-92.1%) in the prolonged delirium group.

Conclusions: Prolonged delirium was found to be associated with a poor functional outcome and increased mortality.

Level of evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

A flowchart shows the flow of patients through the study.

Fig. 2

Kaplan-Meier survival curves show the survival rates at 40 months were 81.0%, 73.5%, and 63.6% for the nondelirium, transient delirium, and prolonged delirium groups, respectively.

Fig. 3

An illustration shows activity changes in the nondelirium, transient delirium, and prolonged delirium groups at final followup. Eighteen of 110 (16.4%) patients in the nondelirium group and 12 of 38 (31.6%) in the transient delirium group were able to ambulate outdoors. Five of eight (62.5%) patients in the prolonged delirium group who were able to ambulate outdoors were housebound at final followup (p = 0.003).