Comparing surgical infections in National Surgical Quality Improvement Project and an Institutional Database

Surgical quality improvement requires accurate tracking and benchmarking of postoperative adverse events. We track surgical site infections (SSIs) with two systems; our in-house surgical secondary events (SSE) database and the National Surgical Quality Improvement Project (NSQIP). The SSE database, a modification of the Clavien-Dindo classification, categorizes SSIs by their anatomic site, whereas NSQIP categorizes by their level. Our aim was to directly compare these different definitions.

NSQIP and the SSE database entries for all surgeries performed in 2011 and 2012 were compared. To match NSQIP definitions, and while blinded to NSQIP results, entries in the SSE database were categorized as either incisional (superficial or deep) or organ space infections. These categorizations were compared with NSQIP records; agreement was assessed with Cohen kappa.

The 5028 patients in our cohort had a 6.5% SSI in the SSE database and a 4% rate in NSQIP, with an overall agreement of 95% (kappa = 0.48, P < 0.0001). The rates of categorized infections were similarly well matched; incisional rates of 4.1% and 2.7% for the SSE database and NSQIP and organ space rates of 2.6% and 1.5%. Overall agreements were 96% (kappa = 0.36, P < 0.0001) and 98% (kappa = 0.55, P < 0.0001), respectively. Over 80% of cases recorded by the SSE database but not NSQIP did not meet NSQIP criteria.

The SSE database is an accurate, real-time record of postoperative SSIs. Institutional databases that capture all surgical cases can be used in conjunction with NSQIP with excellent concordance.