By Accountable Care Journal-
NHS Digital has today updated the Summary Hospital-level Mortality Indicator (SHMI). The SHMI reports on mortality at trust level across the NHS in England. Methodological changes will be made from the 16 May 2019 publication.
What is the SHMI?
The SHMI is the ratio between the actual number of patients who die following hospitalisation, and the number that would be expected to die on the basis of average England figures.
The SHMI can be used by hospital trusts to compare their mortality outcomes to the national baseline. However, it should not be used to directly compare mortality outcomes between trusts and it is inappropriate to rank trusts according to their SHMI.
It covers all deaths reported of patients who were admitted to non-specialist acute trusts in England and either die while in hospital or within 30 days of discharge.
The expected number of deaths is calculated from statistical models derived to estimate the risk of mortality based on the characteristics of the patients, including the condition the patient was in hospital for, other underlying conditions the patient suffered from, age, gender, method and month of admission to hospital, and birthweight (for perinatal diagnosis groups only).
How is it changing?
From the May 2019 publication onwards, a breakdown of the data by site of treatment will be available alongside the trust level results. This new breakdown is being published as an experimental statistic.
All output counts will now be rounded to the nearest five, with the underlying SHMI values calculated from the unrounded values. This is to ensure consistency with the Hospital Episode Statistics disclosure control methodology.
The SHMI is now composed of 142 different diagnosis groups which are aggregated to calculate the overall SHMI value for each trust. The increase from 140 diagnosis groups has been made to improve the accuracy of the indicator.
Also from May 2019, the SHMI will be published on a monthly basis rather than every quarter. Each publication will include discharges in a rolling twelve-month period.
Full details of all the updates are available in the methodological changes document which is available to download here.