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 = 0.860.99), 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 postopera-tive delirium substantially differ based on preoperative dementia status. J Am Geriatr Soc 59: 2306-2313, 2011.