The Association Between Preoperative International Normalized Ratio Values and Postoperative Outcomes including Mortality in Geriatric Femoral Neck Fractures Treated With Hemiarthroplasty

Abstract

Objectives: To evaluate the association between preoperative international normalized ratio (INR) and postoperative mortality and other outcomes after hemiarthroplasty for geriatric femoral neck fractures. Design: Retrospective cohort study. Setting: A single Level-I trauma center. Patients/Participants: Patients ≥55 years of age with OTA/AO 31B proximal femur fractures [1556 patients (1616 hips)] Intervention: Hip hemiarthroplasty. Main Outcome Measurements: Ninety-day mortality, postoperative transfusion within 72 hours, and 90-day postoperative outcomes. Results: Adjusting for confounders, the association of preoperative INR and 90-day mortality was not statistically significant [hazard ratio (HR): 1.3; 95% confidence interval (CI): 0.97, 1.8; P = 0.08]. Dementia (HR: 1.9; 95% CI: 1.4–2.6; P < 0.001), Charlson Comorbidity Index (HR: 1.1; 95% CI: 1.1–1.2; P < 0.001), and age by decade (HR: 1.4; 95% CI: 1.1–1.8; P = 0.002) were associated with 90-day mortality. Increasing INR was significantly associated with blood transfusion [odds ratio (OR) 1.4; 95% CI 1.03–1.6; P = 0.031]. Preoperative hemoglobin <10 g/dL (OR 13.7; 95% CI 8.4–23.3; P < 0.001) was also associated with a postoperative transfusion, whereas intraoperative tranexamic acid use (OR 0.3; 95% CI 0.2–0.5; P < 0.001) was inversely associated with postoperative transfusion rate. INR was associated with superficial wound infection (HR: 2.0; 95% CI: 1.1–3.7; P = 0.02) and noninfected wound complications (HR: 1.6; 95% CI: 1.1–2.4; P = 0.007). Risk of superficial infection increased when INR was >1.8. Conclusion: When controlling for confounders, preoperative INR was not significantly associated with 90-day mortality. Underlying medical conditions contribute to postoperative mortality more than an elevated INR. However, INR is associated with superficial wound complications. This risk becomes statistically significant as INR rises above 1.8. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.