Predictors of Ischemic Stroke After Hip Operation: A Population-Based Study

BACKGROUND: Hip operation (total hip arthroplasty [THA] or fracture repair) is the most common noncardiac surgical procedure performed in patients age 65 years and older. OBJECTIVE: To determine the predictors of ischemic stroke in patients who have undergone hip operation. DESIGN: Population-based historical cohort study, in which postoperative ischemic strokes were identified from medical record review for stroke diagnostic codes and brain imaging results and were confirmed by physician review. SETTING: Tertiary care center in Olmsted County, Minnesota. PATIENTS: Residents of Olmsted County who underwent hip surgical procedure. MEASUREMENTS: Incidence of ischemic stroke within 1 year of hip operation. RESULTS: In total, 1606 patients underwent 1886 hip procedures from 1988 through 2002 and were observed for ischemic stroke for I year after their procedure. Sixty-seven ischemic strokes were identified. The rate of stroke at 1 year after hip operation was 3.9%. In univariate analysis, history of atrial fibrillation (hazard ratio [HR], 2.16; P = 0.005), hip fracture repair vs. total hip arthroplasty (HR, 3.80; P < 0.001), age 75 years or older (HR, 2.20; P = 0.02), aspirin use (HR, 1.8; P = 0.01), and history of previous stroke (HR, 4.18; P < 0.001) were significantly associated with increased risk of stroke. In multivariable analysis, history of stroke (HR, 3.27; P < 0.001) and hip fracture repair (HR, 2.74; P = 0.004) were strong predictors of postoperative stroke. CONCLUSIONS: This population-based historical cohort of patients with hip operation had a 3.9% cumulative probability of ischemic stroke over the first postoperative year. Hip fracture repair and history of stroke were the strongest predictors of this complication. Journal of Hospital Medicine 2009;4:298-303. (C) 2009 Society of Hospital Medicine.