Risk factors for coronary artery bypass graft chest surgical site infections in New York State, 2008

BackgroundAll hospitals in New York State (NYS) are required to report surgical site infections (SSIs) occurring after coronary artery bypass graft surgery. This report describes the risk adjustment method used by NYS for reporting hospital SSI rates, and additional methods used to explore remaining differences in infection rates.MethodsAll patients undergoing coronary artery bypass graft surgery in NYS in 2008 were monitored for chest SSI following the National Healthcare Safety Network protocol. The NYS Cardiac Surgery Reporting System and a survey of hospital infection prevention practices provided additional risk information. Models were developed to standardize hospital-specific infection rates and to assess additional risk factors and practices.ResultsThe National Healthcare Safety Network risk score based on duration of surgery, American Society of Anesthesiologists score, and wound class were not highly predictive of chest SSIs. The addition of diabetes, obesity, end-stage renal disease, sex, chronic obstructive pulmonary disease, and Medicaid payer to the model improved the discrimination between procedures that resulted in SSI and those that did not by 25%. Hospital-reported infection prevention practices were not significantly related to SSI rates.ConclusionsAdditional risk factors collected using a secondary database improved the prediction of SSIs, however, there remained unexplained variation in rates between hospitals.