Independent, Differential Effects of Delirium on Disability and Mortality Risk After Hip Fracture

Abstract

Objectives: To assess the independent effect of delirium on mortality and disability after 1 year of follow-up, in consecutive older patients with hip fracture hospitalized for surgical repair.

Design: This is a prospective observational study.

Setting and participants: Patients aged older than 65 years consecutively admitted for hip fracture to the Trauma and Orthopedics Centre of a third-level hospital, between March and October 2014.

Methods: Patients were evaluated by a multidisciplinary team. A comprehensive geriatric assessment was performed on admission. Delirium was assessed before and after surgical repair according to the Confusion Assessment Method. Mortality and disability status were collected at 3 months and 1 year after hospital discharge.

Results: Of 411 patients with hip fracture, 387 (mean age 82 years, female 72%) were enrolled. Delirium was assessed in 50% of the enrolled population. Patients with delirium were older, frequently affected by dementia, severe prefracture disability, history of falls, and polypharmacy. One-year mortality was 19% in all populations, and higher in patients with delirium, although delirium did not show an independent association with mortality, in multivariable analysis. Conversely, delirium was identified as an independent prognostic factor of long-term disability (B-1.605, SE 0.211, P < .001).

Conclusion and implications: This study identifies delirium as an independent long-term disability generator, regardless of associated clinical conditions and premorbid cognitive and functional status. This emphasises the importance of delirium prevention through a multidisciplinary approach and the potential role of systematic treatment of risk factors in reducing functional decline, even in subjects with preexistent disability and dementia. Moreover, these data call for research on rehabilitation interventions specifically targeted to these complex patients, with the aim of identifying approaches effective in reducing long-term disability. Conversely, a high level of clinical alertness is required in patients with delirium, as an appropriate treatment of acute diseases should reduce their high mortality risk.

Keywords: Delirium; functional status; hip fracture; mortality; multidisciplinary.