Understanding and using the hospital standardized mortality ratio in Canada: challenges and opportunities

In 2005, the Canadian Institute for Health Information (CIHI) began a methodological journey to develop a Canadian version of the hospital standardized mortality ratio (HSMR). For two years, CIHI worked with hospitals, regional authorities and measurement experts to define the most appropriate methodology given Canadian datasets and systems of care. In November 2007, we made the findings publicly available for regional health authorities and larger facilities. In their lead article, Penfold et al. discuss their views regarding some methodological issues and potential limitations of the HSMR to monitor quality of care and, in particular, as a patient safety indicator. Here we respond to their specific concerns and maintain that the HSMR remains an important tool in the arsenal of information hospitals can use to focus the discussion of patient safety/quality improvement, monitor the provision of care over time and identify opportunities for improvement.