What are risk adjusted mortality measures and why they are important for learning from deaths?

For hospital leaders, navigating mortality data can be a complex task.

When the board asks: ‘Which mortality measures should we be looking at?’, a nuanced answer is often not enough to provide necessary insight to effect change.

Understanding how risk adjusted mortality measures are created and how the most common measures differ is essential for patient safety leads and performance leads to enable trusts deliver against learning from deaths.??

The mortality rate or the number of deaths in a hospital or service over a period of time is not easy to compare between different hospitals or different services within a hospital or even in the same ward across different years.

The number of patients who die generally depends on the age, why they have been brought into hospital and how many other health problems they already have.

All of these can vary greatly between different patient groups and comparing like with like is difficult.??

Risk adjusted mortality measures use historic patient data to predict how many patients will be expected to die in a specific patient group. In the UK there are three risk adjusted mortality measures that are commonly used these are:?

• Risk Adjusted Mortality Indicator (RAMI): A measure created by CHKS using a wider dataset to make comparison between different models of care more accurate adjusting the number of expected deaths for the length of stay in hospital?

• Summary Hospital-level Mortality Indicator (SHMI): Developed by NHS England to monitor all hospital trusts in England using some data from patients who die after they are discharged from hospital.?

• Hospital Standardised Mortality Ratio (HSMR): One of the early versions of risk adjusted mortality measures which includes adjustments for some factors the others do not such as deprivation or the number of times a patient has already been admitted to hospital?

Each of the risk adjusted mortality measures have different strengths and weaknesses and getting a good understanding of how they are calculated helps boards and those responsible for learning from deaths ensure they have an evidence-based approach to the review, investigation, reporting and learning from deaths.??

CHKS have created a simple guide to risk adjusted mortality measures which is available here:

Download Guide to Risk Adjusted Mortality Measures

Our report clearly explains the way that each measure is calculated with insight into which one or combination of measure would best suit your organisation.?

"CHKS' mortality review reports with peer comparisons allow us to identify areas excelling and those needing improvement. The data facilitates internal and external benchmarking, supporting quality improvement efforts. The learnings help us focus on areas where patient pathways can be enhanced."?

Dr. Susie Orme, Associate Medical Director, Barnsley Hospital NHS Foundation Trust?