Sharon L. Trivette

OBJECTIVE: To determine mortality, morbidity, and costs attributable to surgical-site infections (SSIs) in the 1990s. DESIGN: A matched follow-up study of a cohort of patients with SSI, matched one-to-one with patients without SSI. SETTING: A 415-bed community hospital. STUDY POPULATION: 255 pairs of patients with and without SSI were matched on age, procedure, National Nosocomial Infection Surveillance System risk index, date of surgery, and surgeon. OUTCOME MEASURES: Mortality, excess length of hospitalization, and extra direct costs attributable to SSI; relative risk for intensive care unit (ICU) admission and for readmission to the hospital. RESULTS: Of the 255 pairs, 20 infected patients (7.8%) and 9 uninfected patients (3.5%) died during the postoperative hospitalization (relative risk [RR], 2.2; 95% confidence interval [CI95], 1.1-4.5). Seventy-four infected patients (29%) and 46 uninfected patients (18%) required ICU admission (RR, 1.6; CI95, 1.3-2.0). The median length of hospitalization was 11 days for infected patients and 6 days for uninfected patients. The extra hospital stay attributable to SSI was 6.5 days (CI95, 5-8 days). The median direct costs of hospitalization were $7,531 for infected patients and $3,844 for uninfected patients. The excess direct costs attributable to SSI were $3,089 (CI95, $2,139-$4,163). Among the 229 pairs who survived the initial hospitalization, 94 infected patients (41%) and 17 uninfected patients (7%) required readmission to the hospital within 30 days of discharge (RR, 5.5; CI95, 4.0-7.7). When the second hospitalization was included, the total excess hospitalization and direct costs attributable to SSI were 12 days and $5,038, respectively. CONCLUSIONS: In the 1990s, patients who develop SSI have longer and costlier hospitalizations than patients who do not develop such infections. They are twice as likely to die, 60% more likely to spend time in an ICU, and more than five times more likely to be readmitted to the hospital. Programs that reduce the incidence of SSI can substantially decrease morbidity and mortality and reduce the economic burden for patients and hospitals.

Data for 479 patients were analyzed to assess the impact of methicillin resistance on the outcomes of patients with Staphylococcus aureus surgical site infections (SSIs). Patients infected with methicillin-resistant S. aureus (MRSA) had a greater 90-day mortality rate than did patients infected with methicillin-susceptible S. aureus (MSSA; adjusted odds ratio, 3.4; 95% confidence interval, 1.5-7.2). Patients infected with MRSA had a greater duration of hospitalization after infection (median additional days, 5; P<.001), although this was not significant on multivariate analysis (P=.11). Median hospital charges were 29,455 dollars for control subjects, 52,791 dollars for patients with MSSA SSI, and 92,363 dollars for patients with MRSA SSI (P<.001 for all group comparisons). Patients with MRSA SSI had a 1.19-fold increase in hospital charges (P=.03) and had mean attributable excess charges of 13,901 dollars per SSI compared with patients who had MSSA SSIs. Methicillin resistance is independently associated with increased mortality and hospital charges among patients with S. aureus SSI.

We evaluated all surgical site infections (SSI) and postoperative bacteremias secondary to SSI as part of an ongoing active surgical surveillance program at a community hospital. Among 40,191 surgical procedures, we identified 515 patients with SSI and 47 with postoperative bacteremia secondary to SSI. Four variables were examined as potential predictors for developing postoperative bacteremia secondary to an SSI: National Nosocomial Infections Surveillance risk index, abdominal surgery, surgical procedures with an implantable device, and the presence of Staphylococcus aureus in wounds. Of these 4 variables, only one, S. aureus isolated from a wound culture, was associated with an increased risk of developing postoperative bacteremia secondary to SSI. Patients with S. aureus isolated in either pure or mixed culture from SSI were more than twice as likely to have postoperative bacteremia secondary to SSI than were those without S. aureus wound infection.