Predisposing factors for postoperative delirium after hip fracture repair in individuals with and without dementia.

OBJECTIVES

Based on a multifactorial model of delirium, to compare the types and magnitude of pre- and intraoperative predisposing factors for incident delirium in a stratified sample of individuals with and without preoperative dementia undergoing acute hip fracture repair.

DESIGN

Prospective cohort study.

SETTING

Academic medical center.

PARTICIPANTS

Four hundred twenty-five individuals with acute hip fracture and without delirium (mean age 80.2 ± 6.8, 73.2% female, 33.1% with probable dementia) admitted to a multidisciplinary hip fracture repair service.

MEASUREMENTS

A research nurse assessed each participant for delirium based on the Confusion Assessment Method (CAM) before study enrollment and from the second postoperative day until hospital discharge.

RESULTS

The incidence of delirium was higher in the group with probable dementia (56%) than in the group without dementia (26%) (P < .001). In the group without dementia (n = 284), age (odds ratio (OR) = 1.07, 95% CI = 1.02-1.13), male sex (OR = 2.81, 95% CI = 1.40-5.64), body mass index (OR = 0.92, 95% CI = 0.86-0.99), number of medical comorbidities (OR = 1.15, 95% CI = 1.01-1.32), and duration of surgery longer than 2 hours (OR = 2.53, 95% CI = 1.20-4.88) were independently associated with postoperative delirium. In the group with probable dementia, only the lag time from the emergency department to operating room was significantly associated (OR = 2.83, 95% CI = 1.24-2.25) with delirium.

CONCLUSION

Preoperative determination of dementia status is important for risk stratification for incident delirium after acute hip fracture repair surgery because types and magnitude of predisposing risk factors for postoperative delirium substantially differ based on preoperative dementia status.