Mortality rates

One of the Trust’s most important quality measures is that of mortality.

How is mortality measured?

There are two main ways to measure mortality:

1. Crude mortality – this is as a percentage calculated by dividing the number of deaths within the organisation by the number of patients treated.

2. Standardised Mortality Ratios (SMR). These are statistically calculated mortality ratios that are heavily dependent on the quality of recording and coding data. These are calculated by dividing the number of deaths within the Trust by the ‘expected’ number of deaths. This expected level of mortality is based on individual, patient specific risk factors that a person will present with on their admission i.e. their diagnosis or the reason for their attending the hospital, their age and their existing medical conditions and illnesses and the type of admission i.e. planned procedure or an unplanned emergency admission.

There are a number of SMRs available but the ‘official’ one for the NHS is the Summary-Hospital Level Mortality Indicator (SHMI) which is published by NHS Digital every quarter.

NHS Digital website

Read more about the SHMI and access the latest figures.

The use of an SMR in assessing and ranking performance must always be interpreted with caution. As these are ratios of actual deaths against ‘expected’ levels of mortality they are heavily dependent on data and the accuracy of recording. As a result of this, there interpretation is likened to that of a smoke alarm, in the same way as the smoke alarm sounding does not mean there is definitely a fire, an SMR indicator of above 100 does not definitely indicate a problem. However, just as it would be unwise to ignore a smoke alarms warning and not investigate, the Trust takes the same view, a high SMR is not ignored it is investigated by a number of methods involving the Trust’s information team and the quality and audit team, alongside clinicians.

Published mortality rates

The Trust’s performance on mortality is monitored by the Trust’s Mortality Performance Committee (MPC) which is chaired by the Trust’s chairman and is a sub-committee of the Trust board. The HSCIC publishes the SHMI figures on a quarterly basis.

As SHMI also includes deaths within the community within 30 days following the discharge from hospital, the data takes time to be completed so is usually between six and 18 months out of date when it is published.

Mortality reports and strategy

Key stats on mortality are discussed at the Trust Board meetings as part of the Integrated Performance Report. View the latest report on the Trust Board meeting pages.

Mortality Improvement Strategy (406KB)
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