HSMR is calculated using statistical models that adjust for variables such as age, sex, diagnosis, comorbidities, and length of hospital stay to fairly compare mortality rates across different institutions and patient populations. A value of 100 indicates that the hospital’s mortality rate matches the national average, while values above or below 100 suggest higher or lower than expected mortality, respectively. Although HSMR is not intended for direct hospital-to-hospital comparisons, it serves as an important tool for internal benchmarking and performance monitoring. Many hospitals use HSMR data alongside clinical audits and other quality measures to identify unexpected deaths and target patient safety improvements.
The adoption of HSMR has been instrumental in guiding healthcare providers to implement evidence-based interventions such as infection control protocols, medication reconciliation, and rapid response teams. Its ongoing use supports transparency and accountability in healthcare delivery by providing actionable insights into mortality trends. While HSMR is a powerful indicator, it is most effective when interpreted in context with other clinical and operational data. Health systems worldwide, including those in Canada, the UK, and Australia, rely on HSMR as part of their quality assurance frameworks to enhance patient care and reduce preventable deaths.
Key features include:
- Measures ratio of observed to expected in-hospital deaths adjusted for patient risk factors
- Enables tracking of hospital mortality trends over time for quality improvement
- Adjusts for demographics, diagnosis, comorbidities, and length of stay
- Supports identification of unexpected deaths for clinical audit and safety interventions
- Widely adopted in healthcare systems for internal benchmarking and performance monitoring
- Facilitates transparency and accountability in patient safety and care quality