Patient activity data in HES can be used to identify if a patient died in hospital. Deaths recorded in HES may be analysed by the main diagnosis for which the patient was being treated, however this data alone cannot be used to determine the underlying cause of death. For example, a patient admitted for a hernia operation (with a primary diagnosis of hernia) may die from an unrelated heart attack. HES data also has the limitation that it does not capture deaths happening outside of hospital. Linking HES with the ONS deaths data addresses these issues.
Using HES data alone to analyse deaths
ONS Mortality Data
The Office for National Statistics (ONS) mortality data contains information related to a person's death taken from the death certificate for all deaths registered in England and Wales. It contains valuable information such as cause of death, date and place of death etc. for neonatal and non-neonatal deaths. Information related to still births is not available in this dataset.
Provisional nature of ONS mortality data
The Office for National Statistics provides mortality data on a monthly basis which is provisional in nature. ONS provisional data has not been subject to full quality assurance and may not contain all deaths which were registered or which occurred during the period. Deaths which occurred in a given year may be registered in a subsequent year. The database remains open to accept these registrations so figures are subject to change. ONS also supplies a final annual refresh of mortality data for the year which is based on calendar year of death registration.