Epidemiology of Surgical-Site Infections Diagnosed After Hospital Discharge A Prospective Cohort Study

Objective:To study postoperative infections in hospital and after discharge, and to identify the risk factors for such infections.Design:Prospective cohort study, with telephone follow-up for 1 month after hospital discharge.Setting:The general surgery service of a tertiary hospital in Spain.Main Outcome Measure:In-hospital and postdischarge surgical-site infection (SSI), always confirmed by a physician.Results:Of the 1,506 patients initially enrolled, 29 died during hospital stay, and 33 were lost to postdischarge follow-up. An SSI was identified prior to discharge in 123 patients and after discharge in 103. For several variables (age, serum albumin, glycemia, lengths of preoperative and postoperative hospital stay, etc), there were no differences between patients with postdischarge SSI and noninfected patients; however, there were differences detected between patients with postdischarge SSI and in-hospital SSI, as well as between patients with in-hospital SSI and noninfected patients. The analysis of risk factors showed that most predictors for in-hospital SSI did not behave in the same manner for postdischarge SSI. Stepwise logistic regression only identified chemoprophylaxis, age (advanced age was a preventive factor), and body mass index as independent risk factors for postdischarge SSI. Differences in risk factors between in-hospital and postdischarge SSIs remained even after controlling for time from operation to diagnosis.Conclusions:Most predictors of in-hospital SSI were not predictors of postdischarge SSI.