The effect of surgical site infection on older operative patients

To determine the effect of surgical site infection (SSI) on mortality, duration of hospitalization, and hospital cost in older operative patients.

Retrospective matched-outcomes study.

Eight hospitals, including Duke University Medical Center, and seven community hospitals.

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.

Mortality, duration of hospitalization (including re-admissions), and hospital charges for the 90 days after surgery.

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).

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).