Category 2000
Health-related outcomes ⏵ Hospital inpatient


This category contains data on hospital inpatient admissions, obtained through linkage to external data providers. Inpatients are defined as persons who are admitted to hospital and occupy a hospital bed. This includes both admissions where an overnight stay is planned and day cases.

Hospital inpatient data are available to researchers in two formats: summary and record-level. Detailed explanations of the how the data was collected and the data formats available can be found in the Resources tab below, in particular in the overview of the Inpatient data (Resource 138483) and the Hospital Inpatient Data Dictionary (Resource 141140).

Summary fields - Diagnoses & Operations

UK Biobank has created summary fields based on the record-level data that provide the first date of any given diagnosis or operation code appearing in each participant's inpatient record.

For diagnoses, there are separate fields for each of ICD-9 & ICD-10 and for both the main diagnosis position and for either main or secondary position. (See Category 2002 below.)

There are similar fields for operations/procedures, for each of OPCS-3 and OPCS-4, both for the main procedure position or any position in the data. (See Category 2005 below.)

For projects needing only information about diagnoses and operations/procedures and their first known occurrence dates these Summary fields should be sufficient and are simpler to work with than the record-level data.

Other Summary fields

There are also other summary fields relating to administration, maternity and psychiatry (Category 2001, Category 2003 and Category 2004 respectively) with each summary field providing an overview of the amount and type of data stored across all inpatient records for that data field for each participant.

These summary fields are not, of themselves, particularly useful for research purposes, but are provided to illustrate the quantity and type of data available in the corresponding record-level tables via the Data Portal.

Record-level inpatient data

A rawer form of the data is available, which consists of seven interrelated database tables: HESIN, HESIN_DIAG, HESIN_OPER, HESIN_CRITICAL, HESIN_PSYCH, HESIN_MATERNITY and HESIN_DELIVERY. These are explained in detail in the overview of the Inpatient data (Resource 138483) and the Hospital Inpatient Data Dictionary (Resource 141140) below.

Due to its size and complexity the record-level inpatient data is accessed via the online Data Portal (via a project's Download page). Access is granted to each table by adding the appropriate field from Category 2006 to a researcher basket.

Researcher publications should use the following citation where data from NHS England has been used: "This work uses data provided by patients and collected by the NHS as part of their care and support."