The Effect of Surgical Site Infection on Older Operative Patients

OBJECTIVES: To determine the effect of surgical site infection (SSI) on mortality, duration of hospitalization, and hospital cost in older operative patients. DESIGN: Retrospective matched-outcomes study. SETTING: Eight hospitals, including Duke University Medical Center, and seven community hospitals. PARTICIPANTS: Patients aged 65 and older undergoing surgery from 1991 to 2003. Cases were defined as patients who developed deep incisional or organ or space SSI; controls were operative patients who did not develop SSI. Controls were frequency matched to cases according to type and year of operative procedure and to hospital in a 1: 1 ratio. MEASUREMENTS: Mortality, duration of hospitalization (including re-admissions), and hospital charges for the 90 days after surgery. RESULTS: One thousand three hundred thirty-seven patients were enrolled in the study: 561 cases with SSI and 576 controls without SSI. In cases, the most common SSI pathogen was Staphylococcus aureus (n=275, 51. 6%). Of S. aureus isolates, 58. 2% were methicillin resistant. One hundred sixteen subjects died within 90 days of surgery (8. 6%). In multivariable analysis, SSI was associated with greater mortality risk (odds ratio (OR) =3. 51, 95% confidence interval (CI) =2. 20-5. 59), 2. 9 times longer postoperative hospitalization (95% CI=2. 61-3. 13), and 1. 9 times greater hospital charges (95% CI=1. 78-2. 10). CONCLUSION: In elderly operative patients, SSI was associated with almost 4 times greater mortality, a mean attributable duration of hospitalization after surgery of 15. 7 days (95% CI=13. 9-17. 6) and mean attributable hospital charges of 43, 970 (95% CI=31, 881-56, 060).