Mortality ratio: deaths in hospital within 30 days of discharge

What this data shows:

Whether the number of deaths for an NHS Trust is higher or lower than expected

How the data is gathered:

This mortality ratio compares the actual number of deaths following time in hospital with the expected number of deaths.  It covers patients admitted to hospitals in England who died either while in hospital or within 30 days of being discharged. Please note COVID-19 activity is excluded from the SHMI. The SHMI is not designed for this type of pandemic activity and the statistical modelling used to calculate the SHMI may not be as robust if such activity were included.

The expected number of deaths takes into account a range of factors that can affect mortality rates, but which are beyond the control of the individual trust (the condition the patient is in hospital for, other underlying conditions the patient suffers from, age, gender and whether the patient was admitted in an emergency).

NHS Trusts are categorised as having either a higher than expected, as expected or lower than expected number of deaths.  For any given number of deaths, a range of observed deaths is considered to be ‘as expected’ (Blue).  If the observed number of deaths falls outside of this range, the trust in question is considered to have a higher (Red) or lower (Green) SHMI than expected.  The extremes of this range are called control limits and full details of their calculation are provided in the SHMI methodology specification, which is available to download from the SHMI homepage at http://digital.nhs.uk/SHMI.

A higher than expected number of deaths should not immediately be interpreted as indicating poor performance and instead should be viewed as a ‘smoke alarm’ which requires further investigation by the Trust. Similarly, an as expected or lower than expected number of deaths should not immediately be interpreted as indicating satisfactory or good performance.Further details on the interpretation of this indicator are available at http://digital.nhs.uk/SHMI

SHMI is not a measure of quality of care. A higher/lower than expected number of deaths should not immediately be interpreted as indicating poor/good performance and instead should be viewed as a 'smoke alarm' which requires further investigation.

SHMI cannot be used to directly compare mortality outcomes between trusts and it is inappropriate to rank trusts according to their SHMI.

More information about the data source:

This indicator is calculated at NHS Trust level, not for individual hospital sites.

Data Source:

NHS Digital

Data Period:

Monthly - Current data is for discharges in the period 1 March 2023 to 30 February 2024

Further Information:

Further information can be found at: https://digital.nhs.uk/data-and-information/publications/statistical/shmi