Hospital Standardized Mortality Ratio

The hospital standardized mortality ratio (HSMR) is an indicator of health care quality that measures whether the number of deaths at a hospital is higher or lower than you would expect, based on the average experience of Canadian hospitals (set at 100 in 2012–2013). The HSMR is calculated by dividing the actual number of in-hospital deaths by the expected number of in-hospital deaths, for conditions accounting for about 80% of inpatient mortality.

HSMR was developed in the United Kingdom in the mid-1990s and is used in hospitals worldwide to assess in-hospital mortality rates and to help organizations identify areas for improvement. HSMR is a quality indicator and a measure to help hospitals and health professionals follow trends in their hospital mortality rates. It is yet another tool to help improve the quality of care and patient safety over time.

Ontario hospitals use HSMR results for internal benchmarking purposes. The reporting of HSMR shows hospitals how their ratio has changed, where they have made progress and where they can continue to improve. Through HSMR, hospitals will, more effectively examine their results, identify areas for improvement, and implement strategies to lower mortality and track results over time.

The Canadian Institute for Health Information (CIHI) has calculated the HSMR for eligible acute care hospitals and regions in Canada. HSMR is the ratio of the actual number of acute in-hospital deaths compared to the expected number of in-hospital deaths, for conditions accounting for 80% of inpatient mortality.

The HSMR is most useful to follow a hospital’s performance over time. The ratio provides a starting point to assess mortality rates and identify areas for improvement to help reduce hospital deaths.

CIHI reports results on an annual basis.