National Obesity Audit, July 2025 - September 2025 [Management Information]

Hospital Episode Statistics (HES)

NHS England (previously NHS Digital) has worked closely with the British Obesity and Metabolic Surgery Society (BOMSS) and policy colleagues to develop a methodology to define how the number of people receiving bariatric surgical procedures can be most accurately derived from HES data. The names of individual bariatric procedures in HES may not directly correspond with the names commonly used by bariatric surgeons, so clinical input has been necessary to help overcome this. NHS England has responded to advice from BOMSS to use a limited code list to identify primary procedures. Whilst the methodology used to derive these statistics has been designed with this input, these numbers should be viewed as developmental until we further refine the methodology with users and stakeholders. Full details of the constructions used are in the metadata document with this release. 

NHS England has historically published data on admissions and number of finished consultant episodes (FCEs) for bariatric surgical procedures in the Statistics on Public Health (SoPH) publication (previously known as Statistics on Obesity, Physical Activity and Diet (SOPAD) publication).  Following a consultation the SoPH now proposes to use the same methodology (in terms of clinical procedure codes) as this National Obesity Audit (NOA) publication. There are some slight differences in reporting where SoPH counts the number of procedures and admissions for bariatric surgical procedures with no separate measures for revisions or gastric balloons.  

Therefore, in liaison with stakeholders and users we will consider whether these figures continue to be published separately from SoPH or whether the 2 publications somehow align in future. You may share your comments on this or any aspect of this publication by emailing [email protected]  (please include ‘NOA’ in the subject line).

Reporting Period

The annual analysis is presented by financial year based on finalised HES data. This is updated once a year.

The quarterly analysis is presented by financial quarter based on both finalised and provisional data, enabling publication of the most recently available information. This is updated 4 times a year. Please note, as the quarterly analysis contains some provisional data, counts may change between publications.

Full details of the HES data extract periods included in this publication release are provided in the Contents chapter.

Weight Management Services (WMS) data in Community Services Data Set (CSDS)

This publication examines the coverage and completeness of certain key fields needed to monitor activity, access and wait times and patient outcomes based on data submitted to CSDS (v1.6) related to WMS. It is not until completeness of these key fields improves that we will be able to publish further meaningful analyses around these services.  Full details of the constructions used are in the metadata document within this release.

The following tables from CSDS v1.6 have been used for the DQ metrics:

• CYP001: Master Patient Index
• CYP102: ServiceTypeReferredTo
• CYP201: Care Contact
• CYP202: Care Activity
• CYP611: Observation

WMS referrals

For the purpose of this analysis, WMS referrals are defined as referrals submitted to CSDS within Table CYP102 with a Service or Team Type Referred To coded as 55 (Children's Weight Management Services)  or 56 (Adult's Weight Management Services). Any referrals submitted without this data field completed will not be captured in the analysis.

Reporting period

The analysis includes new referrals received within the named quarter, and care contact appointments up to one month after the quarter end. For example, for Q1, April to June 2024, the extended period for care contact appointments is April to July 2024. This is to allow more time for referrals to have had a first care contact appointment within the reporting period. Depending on when the new referral date falls in the reporting period, some patients may still be waiting for a first care contact appointment, some will have had one care contact appointment and some may have had multiple care contact appointments. Please note, whilst all data within the reporting period is based on finalised ‘refresh’ data, provisional 'primary' data (which is subject to change) is also used for the extended period of one month in order to capture care contact appointments. 

BMI derivations

BMI can be captured within CSDS in a number of different ways. The methodology looks at where height and weight measurements have been taken simultaneously from the information submitted to CSDS in the Observation Value and UCUM unit of measurement fields in Table CYP202, where Observation Value is not null with a corresponding valid UCUM unit of measurement relating to height and weight. This information can be used to derive BMI. NHS England has also checked for BMI measurements in the Observation Value field with a corresponding valid UCUM unit of measurement relating to BMI.  The guidance states for information to be submitted to CYP202 (as this is where clinical codes can be submitted to support any measurements recorded) but NHS England has also checked for any Height and Weight information being submitted in Table CYP611 (which is for those for those providers that don't yet use clinical codes).

Tier 2 and Tier 3 providers

For the purpose of the analysis, providers of WMS who have been captured in this publication have been categorised as either a Tier 2 or a Tier 3 provider (or both) based on information collected internally.  An Excel file containing this information is available to download in the Resources section of the Overview chapter.