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Hospital Episode Statistics (HES) and Office for National Statistics (ONS) linked mortality data guide

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Hospital Episode Statistics (HES) and Office for National Statistics (ONS) linked mortality data guide


Introduction

Hospital Episode Statistics (HES) data contains clinical information on patients’ hospital activity and treatment such as diagnoses and procedures. It also includes information on the circumstances under which a patient was admitted (such as elective, emergency etc.) and discharged (discharged with clinical consent, died etc.). Information on patients who die in hospital can be analysed on the basis of their primary diagnosis, but HES data alone cannot be used to identify the cause of death. In addition, HES data cannot be used to obtain information on patients who died after discharge from hospital.

The Office for National Statistics (ONS) mortality data is a richer source of information on deaths than HES, with data on the place of death and the underlying cause of death which takes into account information provided by medical practitioners and/or coroners. Linking ONS mortality data to HES data allows the analysis of deaths in and outside hospital for all patients with a record in HES. It is also a rich source of data for analysis on a wide range of subjects including outcomes of hospital care such as postoperative mortality (deaths within a certain number of days of surgery) and tracking performance of healthcare providers and outcomes of treatment over time. It is to be noted that the linked data contains mortality information only on people who have been treated in hospitals.

The purpose of this guidance is to provide details of the data linkage methodology.

Information on the fields included in the HES-ONS linked data set can be found in the HES Technical Output Specification (TOS)


Last edited: 25 May 2023 1:00 pm