A new nationwide method for calculating NHS mortality rates has been unveiled following a national review.
The Summary Hospital-level Mortality Indicator (SHMI) will apply to the NHS in England but will not be used in league tables.
Instead, it is intended to help hospitals better understand trends associated with patient deaths and will replace a variety of methods currently used.
SHMIs are intended to compare the observed number of deaths that actually occurred at a hospital with a statistical estimate of the number of deaths that might have been expected, based upon national average death rates and the particular characteristics of the patients treated in each hospital.
An agreement reached by the review group that produced SHMI decided it cannot be used to rank hospitals in league tables or as a standalone indication of quality.
The Department of Health (DoH) said the indicator will:
• help ensure patient safety by providing an early trigger to probe potential problems;
• cover deaths relating to all admitted patients that occur in all settings - including those occurring in hospital and those occurring 30 days post-discharge;
• apply to all NHS acute trusts except specialist hospitals;
• and adjust as far as possible for factors outside of a hospital's control that might impact on hospital mortality rates.
The need for a new approach was prompted by the Francis Review into Mid Staffordshire NHS Foundation Trust, which recommended that an independent working group should be set up 'in view of the uncertainties surrounding the use of comparative mortality statistics in assessing hospital performance and the understanding of the term ‘excess' deaths.'
The DoH said hospital mortality ratios are complex indicators and changing the approach to calculating NHS rates will lead to greater clarity.
"Variation among existing methodologies and the complex nature of the issue has also caused confusion among NHS managers, clinicians and patients," it added.
Ian Dalton, who chaired the review as chief executive of NHS North East and is now the director of provider development at the Department of Health, believes the result is a significant achievement.
"We now have a wide-ranging consensus not only on the best way to measure mortality but also on how this measure should be used," he said.
"A high SHMI on its own is not an indication of poor standards of care but it is a trigger to take action. Hospital boards across the country have a responsibility to pursue questions the SHMI might raise and quick action will help to ensure safe care for patients at all times," he added.
