Follow Us


NHSE Subsegment / Condition Definitions

A national data-driven approach to population segmentation has been developed to support Population Health Management (PHM) outlined in the NHS Long Term Plan. The subsegment and condition definitions in this section provide further detail on the business rules that have been applied to the data sources.

Read more about the background to segmentation, which includes how the project and the Segmentation Dataset output is delivered as part of this initiative.



These pages provide further details on the business rules that have been applied to create each of the subsegments (conditions) used in the Segmentation Dataset. The conditions are organised into the following segments which can be selected at the top of the page. For further information on how the segments and subsegments relate to each other see the next page, “Segment Configuration”.

  • Long Term Conditions 
  • Disability 
  • Incurable Cancer
  • Organ Failure
  • Frailty and Dementia
  • Maternal Health

Detailed Overview

The Bridges to Health National Segmentation Dataset has been produced, maintained and updated regularly since 2019 to support operational functions, care planning and improvement and service evaluation within NHS England. The dataset currently covers a longitudinal period starting from April 2016 until March 2023, with monthly granularity. The dataset includes all individuals registered with a GP in England, and assigns individuals into a number of conditions (‘subsegments’), each derived using a combination of business rules and code clusters. The subsegments are categorised as cohorts of the population with similar needs and characteristics. These are either specific long-term conditions (eg. Atrial Fibrillation), aggregated conditions group (eg. Coronary Heart Disease includes individuals with myocardial infarction or angina), or ‘nested’ conditions (eg. all COPD and Severe COPD, as a subset). In addition, the dataset includes associated socio-demographic data (age, sex, ethnicity and socioeconomic deprivation), and geographical data (registered GP practice, mapped to administrative NHS organisations and aggregated geographies).

The Segmentation Dataset is derived from a number of national operational and care planning pseudonymised patient-level data sources available in the National Commissioning Data Repository in NHS England. This includes more than 15 years of longitudinally accrued data from Secondary Uses Services (SUS – a collection of data from all hospitals in England, including admitted patient care data, outpatient data, and emergency care data), Mental Health Data, Community Data, IAPT, amongst others, as well as Master Patient Index data which holds non-clinical data on the GP registered population in England including those who have died and GP registration history since 2014, and the National Diabetes Audit extracted from participating GP practices. Otherwise no additional clinical data from GP practices is included at source.

These data sources are run through a series of analytical data pipelines which link the data by pseudonymised NHS number, and apply business rules for combinations of code clusters (ICD-10, OPCS, SNOMED), relevant ‘flags’, and logic to define each subsegment between and within the source datasets. The earliest recording of the specified business rules in at least one of the source operational datasets creates a flag for that individual. These data definitions have been developed through extensive clinical review and evaluation.

Data Governance

Data is collected and used in line with NHS England’s purposes as required under the statutory duties outlined in the NHS Act 2006 and Health and Social Care Act 2012. Data is processed using best practice methodology underpinned by a Data Processing Agreement between NHS England and Outcomes Based Healthcare Ltd (OBH), who produce the Segmentation Dataset on behalf of NHS England. This ensures controlled access by appropriate approved individuals, to anonymised/pseudonymised data held on secure data environments entirely within the NHS England infrastructure. Data is processed for specific purposes only, including operational functions, service evaluation and service improvement. Where OBH has processed data, this has been agreed and is detailed in a Data Processing Agreement. The data used to produce this analysis has been disseminated to NHS England under Directions issued under Section 254 of the Health and Social Care Act 2012.

Segment Configuration

The visual below shows how each Segment in the Bridges to Health segmentation model is defined by a set of Subsegments/Conditions within the Segmentation Dataset, and how the Healthy / Generally Well segment is defined as people who do not meet the criteria of any other core Segment.

Colour-coded table defining each segment by the subsegment(s) it contains, whilst also depicting the relationship between the segments.

Data Sources Used

The Segmentation Dataset is derived from a number of national operational and care planning pseudonymised patient-level data sources available in the National Commissioning Data Repository in NHS England. The following table summarises the data sources used and the number of years of data that has been longitudinally accrued.

Source datasets including time periods used to generate the National Bridges to Health Segmentation Dataset.