Poor functional status as a risk factor for surgical site infection due to methicillin-resistant Staphylococcus aureus

Objective. To identify risk factors for surgical site infection (SSI) due to methicillin-resistant Staphylococcus aureus (MRSA). Design. Prospective case-control study. Setting. One tertiary and 6 community-based institutions in the southeastern United States. Methods. We compared patients with SSI due to MRSA with 2 control groups: matched uninfected surgical patients and patients with SSI due to methicillin-susceptible S. aureus (MSSA). Multivariable logistic regression was used to determine variables independently associated with SSI due to MRSA, compared with each control group. Results. During the 5-year study period, 150 case patients with SSI due to MRSA were identified and compared with 231 matched uninfected control patients and 128 control patients with SSI due to MSSA. Two variables were independently associated with SSI due to MRSA in both multivariable regression models: need for assistance with 3 or more activities of daily living (odds ratio [OR] compared with uninfected patients, 3.97 [95% confidence interval {CI}, 2.18-7.25]; OR compared with patients with SSI due to MSSA, 3.88 [95% CI, 1.91-7.87]) and prolonged duration of surgery (OR compared with uninfected patients, 1.98 [95% CI, 1.11-3.55]; OR compared with patients with SSI due to MSSA, 2.33 [95% CI, 1.17-4.62]). Lack of independence (ie, poor functional status) remained associated with an increased risk of SSI due to MRSA after stratifying by age. Conclusions. Poor functional status was highly associated with SSI due to MRSA in adult surgical patients, regardless of age. A patient's level of independence can be easily determined, and this information can be used preoperatively to target preventive interventions.