The need for unique risk adjustment for surgical site infections at a high-volume, tertiary care center with inherent high-risk colorectal procedures

The aim of the present study was to create a unique risk adjustment model for surgical site infection (SSI) in patients who underwent colorectal surgery (CRS) at the Cleveland Clinic (CC) with inherent high risk factors by using a nationwide database. The American College of Surgeons National Surgical Quality Improvement Program database was queried to identify patients who underwent CRS between 2005 and 2010. Initially, CC cases were identified from all NSQIP data according to case identifier and separated from the other NSQIP centers. Demographics, comorbidities, and outcomes were compared. Logistic regression analyses were used to assess the association between SSI and center-related factors. A total of 70,536 patients met the inclusion criteria and underwent CRS, 1090 patients (1.5%) at the CC and 69,446 patients (98.5%) at other centers. Male gender, work-relative value unit, diagnosis of inflammatory bowel disease, pouch formation, open surgery, steroid use, and preoperative radiotherapy rates were significantly higher in the CC cases. Overall morbidity and individual postoperative complication rates were found to be similar in the CC and other centers except for the following: organ-space SSI and sepsis rates (higher in the CC cases); and pneumonia and ventilator dependency rates (higher in the other centers). After covariate adjustment, the estimated degree of difference between the CC and other institutions with respect to organ-space SSI was reduced (OR 1.38, 95% CI 1.08-1.77). The unique risk adjustment strategy may provide center-specific comprehensive analysis, especially for hospitals that perform inherently high-risk procedures. Higher surgical complexity may be the reason for increased SSI rates in the NSQIP at tertiary care centers.