Surgical site infections in elderly fragility hip fractures patients undergoing warfarin treatment

OBJECTIVES: Surgical site infection (SSI) is a devastating complication of proximal femoral fracture surgery, related with an increased morbidity and mortality. As warfarin treatment has been described as a risk factor for SSI, we aimed to compare patient and SSI characteristics in warfarin and nonanticoagulated patients. DESIGN: Retrospective cohort study. SETTING: Level-1 trauma center. PATIENTS: Individuals 65 years of age and older with fragility hip fractures. INTERVENTION: Patients were divided into 2 cohorts: warfarin treated (n = 85) or nonanticoagulated (n = 771). Demographics, in-hospital characteristics, laboratory data, prior hospitalizations, recent antibiotic use, and 1-year incidence of SSIs and their characteristics were gathered. MAIN OUTCOME MEASURES: Postoperative SSIs. RESULTS: Twelve patients (14.1%) from the warfarin group and 21 patients (2.7%) from the noncoagulated group had SSI (P < 0.001). Both groups were comparable in terms of demographics and Charlson comorbidity score. Warfarin-treated patients had reduced white blood and neutrophils counts (10.1 ± 3.2 vs. 11.6 ± 4.0 cells/mm and 8.1 ± 3.2 vs. 9.6 ± 3.9 cells/mm for both comparisons respectively; P < 0.001 for both). They were more likely to be admitted to a geriatric ward than to orthopedics ward and were delayed to theater (58.5 ± 44.5 vs. 30.6 ± 27.4 hours; P < 0.001). Following surgery, there was no difference in blood transfusions required, in-hospital complications, or time to infection. Rates of prior hospitalizations, antibiotic use, or type of bacteria did not differ. CONCLUSIONS: Warfarin treatment in fragility hip fracture surgery is correlated with an increased risk for SSI, regardless of in-hospital complications, and hospitalizations before surgery or to the infection itself. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.