INTRODUCTION 2022

The United Kingdom National Bariatric Surgery Registry Publication of Surgeon-level data in the public domain for bariatric surgery in NHS England

Summary

The NBSR Committee on behalf of the British Obesity and Metabolic Surgery Society presents the outcomes data for NHS patients having bariatric surgery for the four financial years from 2017/18 to 2021/22 on https://nbsr.e-dendrite.com. The main results are summarised in the tables below from the data cut taken on 24^th November 2022, with the 2012/19 data copied through from the 2018/19 Report. This report covers clinical activity during the COVID-19 pandemic when many hospitals and surgeons did not perform Bariatric Surgery and the recovery period when services were restarting.

As before, all NHS data are included and there were no non-contributing hospitals. The total number of hospitals includes private hospitals, where used, to provide additional capacity for the NHS bariatric units. The data shown are those of surgeons currently practising within the NHS for the 4 years reported in this Clinical Outcomes Publication (COP).

* These data include all primary and revision surgery, without subdividing revision surgery. Therefore, the numbers are likely to include re-operations for complications of the primary procedure) as well as conversions to another bariatric procedure. There are a few cases each year which are not classified within NBSR as either primary or revisional surgery.

** The historic HES data volumes may be slightly different from those recorded in previous COP reports due to adjustments made by the HSCIC. Case ascertainment is recorded as primary operations in NBSR / HES recorded data (%). However due to differences in the way bariatric procedures are coded within HES, this methodology of case ascertainment has some limitations. 

*** The NBSR mortality data we report are in-hospital deaths and exclude patients who may be readmitted and die due to a complication of surgery within 30 days. The data are adjusted compared to previously reported, since entries on the registry have been changed/edited by contributing surgeons.

**** Data suppressed from HES as low numbers to prevent potential identification of individual patients. 

 Mortality statistics according to Hospital Episode Statistics (HES) are shown on the following table and record both the number of deaths in hospital and within 30 days of surgery.

* Small numbers have been suppressed for these years.

BACKGROUND

The first round of Consultant Outcomes Publication in 10 specialties, including bariatric surgery, in summer 2013, followed a call for a culture of openness, transparency and candour from the Francis Report (2013)¹ that dealt with the events leading up to the Mid Staffordshire inquiry. The NBSR publishes its 7th round of outcomes data for surgeons and units in the NHS in England. 

2017 saw the launch of version 2 of the NBSR reporting website for consultants. The NBSR Committee has repeated the outcome measures used for the 2017/18 COP report which include:

• Publishing the names of the hospitals whose total patient records were >10% fewer than they should be according to HES (though we know that codes used by HES are not completely clear for different primary and revisional bariatric procedures)
• Adding the percentage of initial patient records that are ‘green for complete’
• Sub-divides revision surgery into major and minor, so as to highlight the work of those who take on higher risk major revisions.

We are well aware of the lack of audit back up in many units and the first two are intended to support bariatric teams in their discussions locally. In particular, teams should audit total procedure numbers against their actual activity and submit any missing data. NBSR committee has sent several reminders to contributors to check and correct this prior to publishing this report. Contributing surgeons should also ensure NBSR teams have their current email addresses. 

In addition to previous outcomes, NBSR has further sub-divided gastric bypass procedures into Roux-en-Y gastric bypass and the One anastomosis Gastric Bypass/Mini Gastric Bypass (OAGB/MGB) which now features in Version 2 of the NBSR reporting website.

OUTCOMES PUBLISHED FOR 2019/20 and 2020/21

• Total number of operations, broken down by common procedures (bands, sleeve gastrectomy, Roux-en-Y gastric bypass and one anastomosis gastric bypass/mini gastric bypass
• Proportion primary vs major revision vs minor revision
• Data completion rates ('green for complete')
• In-hospital mortality
• The names of hospitals whose NBSR entries are more than 10% fewer than they should be according to Hospital Episodes Statistics (HES) (poor case ascertainment)
• Data completion rates for the initial in-patient record according to the proportion of records that are ‘green for complete’ for each surgeon
• Reporting of revisional surgery rates according to major and minor, expressed as % of workload of each surgeon.

NOTES ON THESE OUTCOMES

1.  Case ascertainment vs Hospital Episodes Statistics (HES)

Following is largely borrowed from the 2013/14 report where we call for NHS trusts to provide sufficient administrative support to help their bariatric teams with data entry:

Most NHS bariatric units don’t have sufficient administrative support to ensure data submission, completeness of data entry, and internal validation although the NBSR became mandatory for NHS providers from 1st April 2013. We, therefore, remind NHS Trusts of their obligation to:

• Ensure and resource team engagement with this national clinical audit; including providing resources for data validation
• Respond to audit provider requests for checking data accuracy and notification of outlying data
• Work with clinicians and audit providers to use audit data for quality improvement
• Promote the value of clinical audit across all work streams, not just those involved with COP ²

Our view remains that it is insufficient to rely on individual clinicians alone to ensure there are no missing records, incomplete records or inaccurate data entry and thus possible under-reporting. Submitting data to NBSR is a combined responsibility of the trust and all the clinicians involved in the multidisciplinary teams.’’

It is possible that individual hospital coding issues are the reason for some of the apparent differences, and these may need assessing locally. Although mandated in the NHS provider contracts, the NBSR committee has no further role other than pointing out the apparent discrepancy.

Our policy on this link https://bomss.org/wp-content/uploads/2022/02/NBSR-Policy-for-Managing-Non-Contribution-of-Patient-Data-March-2015.pdf may help clarify our position further. 

2.  Data completion rates – initial record ‘green for complete’

The First NBSR Report details the data fields that need to be completed to make the record go green³.  If one or more field is missing the data record will remain yellow for incomplete.  The fields are:

Initial information

• Weight
• Height
• Hospital name
• Funding Category

Baseline comorbidity

• ASA grade
• Type 2 Diabetes and duration (where applicable)
• Hypertension
• Cardiovascular
• Sleep apnoea
• Asthma
• Functional Status
• Known risk factors for pulmonary embolus

Operation Record

• Type Of Operation (Primary, Revision or Planned Second Stage)
• Operative approach (Laparoscopic, Lap converted to Open, Open, Endoscopic)
• Operation (select relevant choice)
• For Revisions Prior Operation Type (where applicable)

Post-op course and discharge

• Cardiovascular complications
• Other complications
• Discharge date
• Discharged destination

'Are the initial data complete' button

Note that the published data are for the 4 years 2017/21 and any records incomplete before the 2018/19 years will still be evident in the current reporting unless they have been updated. Thus, a hospital with a local version of the database that was not collecting the relevant record for ‘green for complete’ before 2018/19 would not change its potential outlier status.

3.  Primary and Revision surgery are here defined as

• Primary surgery: the first bariatric operation
• Minor revision: all operations for later complications of surgery, which may or may not involve laparoscopy or laparotomy, and includes band port and band removal procedures
• Major revision: where one operation is converted to another bariatric operation, including planned second stage procedures

Minor revision surgery includes reoperations for complications of all bariatric procedures, ranging from more minor reoperations on for instance a subcutaneous gastric band port to more major reoperations for complications eg a leak from or stricture in a staple line, or bleed from a gastric bypass or sleeve gastrectomy. The definition also includes re-operations for internal hernia (twisted bowel) that can occur after some types of surgery. Operations such as cholecystectomy are not recorded as revisions with this definition.

Major revision surgery includes an operation for instance where a vertical banded gastroplasty (now obsolete) is converted to a gastric bypass, or a band procedure is added to a gastric bypass. Experienced surgeons may be more likely to perform more major revisional surgery, compared to younger, newly appointed consultants.

Future reports may sub-divide ‘Minor revision surgery’ into local procedures not involving laparoscopy/laparotomy, and more invasive procedures that involve laparoscopy/laparotomy since the current definition encompasses a wide range of invasiveness. Future reports may also include post-operative complications occurring within or after 30 days of the index procedure.

MORTALITY RATES AND VALIDATION FROM HES

We use the same methodology to calculate in-hospital and 30-day mortality as for the 2013/2017/2020 reports ^3-5. The definition of in-hospital death used for the NBSR and HES reporting is - a death that occurs during the initial hospital stay before discharge.

It is our policy that all mortalities related to bariatric surgery should be reported into the registry, but we are not able to comment on any mortality that is not. 

Overall, the NBSR data and the various HES analyses are similar to a US benchmark, the American College of Surgeons Bariatric Surgery Center Network, where the published mortality rate was 0.12% (35 out of 28,616) for patients operated from 2007-10⁶.

OTHER OUTCOMES REPORTED 

These are:

• Consultant workload for primary and revision operations excluding gastric balloon placement
• Operation split by consultant
• BMI on entry into the weight loss programme 
• Co-morbidity count per type of operation (number of co-morbidities recorded per patient)
• Obesity-Surgery Mortality Risk Score (OS-MRS) and class per operations and overall per consultant
• Initial BMI overall per consultant (box and whiskers)
• Length of stay for primary procedures compared to the rest per consultant
• In-hospital mortality, described as survival

The co-morbidity count was taken from the NBSR dataset of co-morbidities:

• Type 2 diabetes
• Hypertension on treatment
• Dyslipidaemia
• Atherosclerosis (includes angina, MI, CABG, stroke, claudication)
• Sleep apnoea
• Asthma
• Functional status (presence of comorbidity defined as unable to climb 3 flights of stairs without resting)
• Back or leg pain from arthritis
• GORD
• Liver disease (suspected NAFLD or worse)
• Poly-cystic ovarian syndrome (female patients only)
• Depression (clinically significant depression as a reason for bariatric surgery)

The Obesity Surgery-Mortality Risk Score is the only validated measure of operative risk for patients undergoing bariatric surgery⁷. A point is added for each of the following risk factors that are present, up to a maximum of 5 points: age at surgery ≥45 years, BMI ≥50 kg m2, male gender, recorded hypertension, one or more known risk factors for deep vein thrombosis (DVT) / pulmonary embolism (PE). Using the resultant score, complication & mortality rates can be risk-adjusted; the higher the score/group, the greater the risk of surgery. Patients can be stratified for risk according to how many of these risk factors are present. It is normal practice to refer to the calculated scores in three groups:

 Group A (0-1 points)
 Group B (2-3 points)
 Group C (4-5 points)

We worked with Device Access to analyse the HES data, and using a refined set of OPCS4 codes were able to estimate the mortality for primary bariatric surgery.

PRESENTATION OF RESULTS 

Patients are able to search for hospitals by geography using an added map function and postcode. See the Frequently Asked Questions section on how to interpret this. As before, we present data for each outcome variable either as graphs, bar charts or box and whiskers graphs. Comments are included interpreting the results.

ACKNOWLEDGEMENT OF SUPPORTING TRUSTS.

The NBSR committee would like to acknowledge voluntary contribution from following trusts towards production of this report and maintenance of the NBSR. This only includes those trusts that have contributed until the time of publication of this report. 

TRUST NAMES:

Royal Cornwall Hospitals NHS Trust

University Hospitals of Derby and Burton NHS Trust

Gloucestershire Hospitals NHS Trust

University Hospitals Leicester NHS Trust

Portsmouth Hospitals University NHS Trust

University Hospitals Plymouth

Sunderland And South Tyneside NHS Trust

INTERPRETATION OF RESULTS

We believe the 4-year data for 2018/22 are a correct representation of surgeon and hospital volume, baseline BMI, degree of baseline obesity-related disease, type of operation, mortality and length of stay.

NBSR Committee, 14th of March 2022

Andrew Currie                                                Kamal Mahawar

Reports Subcommittee Lead                          Chair, National Bariatric Surgery Registry

Contact details

The NBSR administrators are contactable by email info@bomss.org or
 Tel: 01543 422 195 or post to:
 Secretariat, BOMSS, C/O EBS, City Wharf, Davidson Road, Lichfield, Staffordshire, WS14 9DZ 

NATIONAL BARIATRIC SURGERY REGISTRY BOOK REPORTS

So far over 100,000 individual patient records have been added since its inception in January 2009 and the First NBSR Report of aggregated operative and disease-related outcomes was published in April 2011³. A Second NBSR Report of aggregated outcomes in 18,000 patients over 3 years was published in November 2014⁴. A third NBSR Report of 38,388 patients, taking the NBSR total to 70,461 up to 2018, was published in 2020 and can be downloaded for free at https://www.e-dendrite.com/NBSR2020⁵

References

¹The Francis Report 2013 Executive Summary http://www.midstaffspublicinquiry.com/sites/default/files/report/Executi...

²HQIP Clinical Outcomes Publication programme 2016-2020. http://www.hqip.org.uk/resources/clinincal-outcomes-publication-2016-2020/

³ First NBSR Report April 2011. http://www.nbsr.org.uk/

⁴Welbourn R, Sareela A, Small P et al. National bariatric surgery registry: second report. 2014 ISBN 978-0-9568154-8-4. 

⁵Small P, Mahawar K et al. The United Kingdom National Bariatric Surgery Registry 3rd Report (2020) ISBN 978-1-9160207-2-6.

⁶Hutter MM, Schirmer BD, Jones DB et al. First Report from the American College of Surgeons Bariatric Surgery Center Network Laparoscopic Sleeve Gastrectomy has Morbidity and Effectiveness Positioned Between the Band and the Bypass. Ann Surg 2011; 254: 410–422. 

⁷DeMaria EJ, Portenier D, Wolfe L. Obesity surgery mortality risk score: proposal for a clinically useful score to predict mortality risk in patients undergoing gastric bypass. Surgery for Obesity and Related Diseases. 2007; 3(2): 134-40.