Using hospital standardised mortality ratios to assess quality of care - proceed with extreme caution.

Abstract

Australian Health Ministers have endorsed the hospital standardised mortality ratio (HMSR) as a key indicator of quality and safety, and efforts are currently underway towards national implementation. In the UK, Canada, the Netherlands and the US, the HSMR has been used for several years within organisations to monitor performance and response to quality and safety programs. In the UK and Canada the HSMR is publicyl reported and used to compare performances between hospitals. The validity and reliability of the HSRM as a tool for distinguishing low-quality from high-quality hospitals remain in doubt, and it has not been proven that HSMR reporting leads to worthwhile improvement in quality of care and patient outcomes. Institutions may respond to an unfavourable HSMR by "gaming" administrative data and risk-adjustment models or implementing inappropriate changes to care. Despite its apparent low cost and ease of measurement the HSMR is currently not "fit for purpose" as a screening tool for detecting low-quality hospitals and should not be used in making comparisons. It may be better to monitor changes in outcomes over time within individual institutions.