Past History of Skin Infection and Risk of Surgical Site Infection After Elective Surgery

Abstract

To identify baseline patient characteristics associated with increased susceptibility to surgical site infection (SSI) after elective surgery. The Center for Medicare and Medicaid Services considers SSI to be preventable through adherence to current infection control practices; however, the etiology of wound infection is incompletely understood. Prospective cohort study involving patients undergoing cardiac, vascular, craniotomy, and spinal surgery at 2 academic medical centers in Baltimore, MD. A comprehensive medical history was obtained at baseline, and participants were followed for 6 months using active inpatient and outpatient surveillance for deep SSI and infectious death. Infection control best practices were monitored perioperatively. The relative risk of SSI/infectious death was determined comparing those with versus those without a past medical history of skin infection using Cox proportional hazards models. Of 613 patients (mean [SD] = 62.3 [11.5] years; 42.1% women), 22.0% reported a history of skin infection. The cumulative incidence of deep SSI/infectious death was 6.7% versus 3.1% for those with and without a history of skin infection, respectively (unadjusted hazard ratio (HR) = 2.25; 95% confidence interval (95% CI), 0.98-5.14; P = 0.055). Risk estimates increased after adjustments for demographic and socioeconomic variables (HR = 2.82; 95% CI, 1.18-6.74; P = 0.019) and after propensity score adjustment for all potential confounders (HR = 3.41; 95% CI, 1.36-8.59; P = 0.009). Adjustments for intraoperative infection risk factors and adherence to infection control best practice metrics had no impact on risk estimates. A history of skin infection identified a state of enhanced susceptibility to SSI at baseline that is independent of traditional SSI risk factors and adherence to current infection control practices.