Use of administrative data for surgical site infection surveillance after congenital cardiac surgery results in inaccurate reporting of surgical site infection rates

Background: The National Healthcare Safety Network (NHSN) is a safety surveillance system managed by the Centers for Disease Control and Prevention that monitors procedure specific rates of surgical site infections (SSIs). At our institution, SSI data is collected and reported by three different methods: (1) the NHSN database with reporting to the Centers for Disease Control and Prevention; (2) the hospital billing database with reporting to payers; and (3) The Society of Thoracic Surgeons Congenital Heart Surgery Database. A quality improvement initiative was undertaken to better understand issues with SSI reporting and to evaluate the effect of different data sources on annual SSI rates.

Methods: Annual cardiac surgery procedure volumes for all three data sources were compared. All episodes of SSI identified in any data source were reviewed and adjudicated using NHSN SSI criteria, and the effect on SSI rates was evaluated.

Results: From January 1, 2008, to December 31, 2011, 2,474 cardiac procedures were performed and reported to The Society of Thoracic Surgeons Congenital Heart Surgery Database. Billing data identified 1,865 cardiac surgery procedures using the 63 CARD International Classification of Diseases-Ninth Revision codes from the NHSN inclusion criteria. Only 1,425 procedures were targeted for NHSN surveillance using the NHSN's CARD operative procedure group in the same period. Procedures identified for NHSN surveillance annually underestimated the number of cardiac operations performed by 17% to 71%. As a result, annual SSI rates potentially differed by 12% to 270%.

Conclusions: The NHSN CARD surveillance guidelines for SSI fail to identify all pediatric cardiac surgical procedures. Failure to target all at-risk procedures leads to inaccurate reporting of SSI rates largely based on identifying the denominator. Inaccurate recording of SSI data has implications for public reporting, benchmarking of outcomes, and denial of payment. Use of The Society of Thoracic Surgeons Congenital Heart Surgery Database as the gold standard to identify procedures for surveillance will lead to more accurate reporting of SSI rates.