A benchmark too far: findings from a national survey of surgical site infection surveillance

Background: The national surgical site infection (SSI) surveillance service in England collates and publishes SSI rates that are used for benchmarking and to identify the prevalence of SSIs. However, research studies using high-quality SSI surveillance report rates that are much higher than those published by the national surveillance service. This variance questions the validity of data collected through the national service.

Aim: To audit SSI definitions and data collection methods used by hospital trusts in England.

Method: All 156 hospital trusts in England were sent questionnaires that focused on aspects of SSI definitions and data collection methods.

Findings: Completed questionnaires were received from 106 hospital trusts. There were considerable differences in data collection methods and data quality that caused wide variation in reported SSI rates. For example, the SSI rate for knee replacement surgery was 4.1% for trusts that used high-quality postdischarge surveillance (PDS) and 1.5% for trusts that used low-quality PDS. Contrary to national protocols and definitions, 10% of trusts did not provide data on superficial infections, 15% of trusts did not use the recommended SSI definition, and 8% of trusts used inpatient data alone. Thirty trusts did not submit a complete set of their data to the national surveillance service. Unsubmitted data included non-mandatory data, PDS data and continuous data.

Conclusion: The national surveillance service underestimates the prevalence of SSIs and is not appropriate for benchmarking. Hospitals that conduct high-quality SSI surveillance will be penalized within the current surveillance service.