Bariatric surgical procedures, 2021/22 (provisional)– National Obesity Audit [Management Information]

This data quality statement aims to provide users with an evidence based assessment of quality of the statistical output included in this publication.  

It reports against those of the nine European Statistical System (ESS) quality dimensions and principles appropriate to this output. The original quality dimensions are: relevance, accuracy and reliability, timeliness and punctuality, accessibility and clarity, and coherence and comparability; these are set out in Eurostat Statistical Law. However more recent quality guidance from Eurostat includes some additional quality principles on: output quality trade-offs, user needs and perceptions, performance cost and respondent burden, and confidentiality, transparency and security. 

In doing so, this meets NHS Digital’s obligation to comply with the UK Statistics Authority (UKSA) code of practice for statistics and the following principles in particular: 

• Trustworthiness pillar, principle 6 (Data governance) which states “Organisations should look after people’s information securely and manage data in ways that are consistent with relevant legislation and serve the public good.” 

• Quality pillar, principle 3 (Assured Quality) which states “Producers of statistics and data should explain clearly how they assure themselves that statistics and data are accurate, reliable, coherent and timely.” 

• Value pillar, principle 1 (Relevance to Users) which states “Users of statistics and data should be at the centre of statistical production; their needs should be understood, their views sought and acted upon, and their use of statistics supported.” 

• Value pillar, principle 2 (Accessibility) which states “Statistics and data should be equally available to all, not given to some people before others. They should be published at a sufficient level of detail and remain publicly available.” 

This dimension covers the degree to which the statistical product meets user needs in both coverage and content. 

This publication is considered to be of particular interest to NHS and independent sector providers in England and to English NHS commissioning organisations. However, data and findings are likely also to be of interest to a much broader base of users. 

This dimension covers, with respect to the statistics, their proximity between an estimate and the unknown true value. 

Procedures from Hospital Episode Statistics (HES) data 

The accuracy of HES data is the responsibility of the NHS providers who submit the data to Secondary Uses Service (SUS). 

Further general information on HES data quality, including specific known issues can be found here: 

https://digital.nhs.uk/data-and-information/data-tools-and-services/data-services/hospital-episode-statistics/the-processing-cycle-and-hes-data-quality 

The data presented in this report are for inpatients only. We have used primary diagnosis of obesity (ICD10 code E66), to limit the bariatric procedures to those related to obesity but there is a small possibility that people undergoing bariatric surgical procedures for cancer may be counted.  

The revision procedure count will not include patients; 

• who had their first bariatric surgical procedure as a non-NHS patient in the private sector, or 

• who had their first bariatric surgical procedure as an NHS patient earlier than 10 years prior to the reporting period year, or 

• who had their first bariatric surgical procedure during the same reporting period year and both surgeries were coded as primary surgeries using one of the 13 primary procedure codes 

Outpatient procedures are not included in these figures due to the primary diagnosis code being poorly populated, and there being no certainty that procedures are for obesity diagnoses. 

In HES, people are identified using the Master Person Service (MPS) person identifier (Person ID). This is a unique identifier for each individual patient, generated via the MPS. HES is a well curated data asset, and most records (over the time period used in the NOA analysis) have NHS number and date of birth (DOB) populated. This means that Person ID matching is mostly based on the most robust tracing step in MPS. Further information on MPS is available here: https://digital.nhs.uk/services/master-person-service  

Children's bariatric surgery 

The methodology used to derive these figures was designed with adults in mind. We aim to refine this methodology further and would welcome feedback on whether these figures are likely representative of the true picture for people aged 0-18 years. 

Timeliness refers to the time gap between publication and the reference period. Punctuality refers to the gap between planned and actual publication dates. 

This is the first release of data to form part of NOA. It is planned that it will be released quarterly and presents the most up-to-date information available, as early as possible. 

This publication uses statistics from the Hospital Episodes Statistics (HES) dataset. HES data for 2021-22 is still provisional and should therefore be treated as an estimate. When the final HES National Statistics 2021-22 annual publication is released later this year, we will update the data in this dashboard. 

Accessibility is the ease with which users are able to access the data, also reflecting the format in which the data are available and the availability of supporting information. Clarity refers to the quality and sufficiency of the metadata, illustrations and accompanying advice. 

All reports are accessible on the NHS Digital website. NHS Digital produced data tables are provided in the dashboard and as csv file, as part of the government’s requirement to make public data public. An accompanying metadata file is provided in MS Excel format which provides a broad definition of each measure, including the data items used. 

Coherence is the degree to which data which have been derived from different sources or methods but refer to the same topic are similar. Comparability is the degree to which data can be compared over time and domain. 

NBSR data 

BOMSS also collect and publish annual data on bariatric surgery through the National Bariatric Surgery Registry (NBSR) which allows surgeons to voluntarily submit data. The key objective of the registry is to accumulate sufficient data to allow the publication of a comprehensive report on outcomes following bariatric surgery. The latest NBSR report was published in 2020 at https://www.e-dendrite.com/NBSR2020  

There are some differences in the data collected by NBSR and HES. The data is collected for different primary purposes with NBSR collecting much broader data, different coding/terms are used for procedures, NBSR includes all adult NHS and private procedures, and not all hospitals submit complete data to NBSR. However, the data are relatively coherent, with large provider differences highlighted on the NBSR website. Full details of NBSR and their reports are on the Bariatric Surgeon Reporting Website (e-dendrite.com) 

NHS Digital and NHS England continue to work together with BOMSS to ensure both NBSR and HES provide reliable data which support improvements in quality of care. 

Data in the Statistics on Obesity, Physical Activity and Diet publication 

NHS Digital has historically published data on admissions and number of finished consultant episodes for bariatric surgical procedures in the National Statistics on Obesity, Physical Activity and Diet (SOPAD) which uses a different methodology, as explained in their Technical notes. SOPAD counts the number of procedures and admissions for bariatric surgery,  groups reporting on primary and revision procedures, excludes gastric balloons and bubbles procedures and uses a wider range of different procedure codes. Therefore the SOPAD figures are higher than the counts of people provided in this release. SOPAD have recently been through a consultation, accessible here: Statistics on Obesity, Physical Activity and Diet - NHS Digital  which didn’t include a revised methodology for these estimates. Therefore, as this dashboard and statistics develop, we will consider in liaison with stakeholders and users, whether these statistics continue to be published separately from SOPAD or realign back into SOPAD with the revised methodology, as part of a new combined compendia publication following the consultation. 

Obesity related hospital admissions 

Changes to the figures over time need to be interpreted in the context of improvements in data quality and coverage, and changes in NHS practice. 

Improved use of secondary procedure codes 

There is continuing evidence that recording of secondary procedure codes is improving over time, which result in a increase in the number of people identified as having a bariatric procedure. 

This dimension describes the extent to which different aspects of quality are balanced against each other. 

New analyses by NHS Digital consist of HES statistics. HES data quality information, including details of trade-offs, is available here: 

https://digital.nhs.uk/data-and-information/data-tools-and-services/data-services/hospital-episode-statistics/the-processing-cycle-and-hes-data-quality 

This dimension covers the processes for finding out about users and uses and their views on the statistical products. 

This is the first release of data to form part of NOA . 

NHS Digital is keen to gain a better understanding of the users of this publication and of their needs; feedback is welcome and may be sent to [email protected] (please include ‘NOA’ in the subject line). 

You may feedback your comments on this using our customer survey https://forms.office.com/r/i9WyhAdYRn

The procedures and policy used to ensure sound confidentiality, security and transparent practices. 

All publications are subject to a standard NHS Digital risk assessment prior to issue. Disclosure control is implemented where deemed necessary. 

The code of practice for statistics is adhered to from collecting the data to publishing. 

Details of relevant NHS Digital procedure and policy information can be found below: 

NHS Digital Statistical Governance Policy 

NHS Digital Freedom of Information Process 

NHS Digital Statement of Compliance with Pre-Release Order 

NHS Digital Disclosure Control Procedure 

HES Disclosure Control