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The evolution of the UK’s National Bariatric Surgery Registry

In October 2023, Mr Omar Khan was appointed as the Chair of the British Obesity & Metabolic Surgery Society’s (BOMSS) National Bariatric Surgery Registry Committee. In this interview, we discuss the evolution of the NBSR, some of the changes he would like to see and the challenges in collecting and reporting patient data…

“The NSBR was established in 2008 and to start with it was very much an audit tool but under the leadership of Richard Welbourn it developed into something a lot more powerful that has allowed us as a speciality to not only showing the long-term safety and efficacy of bariatric surgery, but also our professional competence by demonstrating the high standards of bariatric surgeons in the UK,” explained Mr Khan, a Consultant Surgeon at St George's University Hospitals NHS Foundation Trust, London. “Another motivation for  the NBSR was to counter  an incorrect perception that bariatric surgery is dangerous. Incredibly, if you were to ask the average member of the public what their perception of bariatric surgery was some 10 -15years ago, they would tell you ‘it’s an unnecessary operation’, ‘a cosmetic procedure’, ‘a dangerous operation and one which actually no one really needed’. The general perception about weight loss was the tired and disapproved adage, ‘eat a bit less and do a bit more.”

He said that over the years, the outcomes from the NBSR have time and again clearly proven to both the general public and all the healthcare providers that globally speaking, when benchmarked against international comparators, bariatric surgery is safe in the UK. The NBSR has also showed that individual surgeons are safe via the Consultant Outcome Publication, demonstrating that not only is surgery safe in the UK,  and that  consistency of safety and effectiveness is demonstrated across all units and centres in the UK.

Outcomes measures

“One of the key benefits of the Registry is that is has a mechanism to identify outliers within the NHS, so they can be dealt with as a matter of urgency. I think that's a testimony to my predecessors and their design of the database, as well as Dendrite, who've been fantastic in

giving us the ability and the assurance that we have a robust system that works and picks up potential problems and demonstrates good results.”

Khan explained that in terms of outliers, the database is essentially identifying mortality. However, he believes that is a blunt outcomes measure, citing the experience of UK cardiac surgeons, who he noted, have been reporting outcomes (mortality) data for more than 25 years. 

Mr Omar Khan

“Our cardiac colleagues soon realised that mortality is crude measure because you could have someone who's not a good surgeon but working in a hospital with a a very good intensive care unit (ICU) where they regularly rescue his/her patients and so their outcomes do not show any significant rise in mortality. Conversely, you could have a very good surgeon who has one mortality and actually suddenly is an outlier because they had a high-risk patient or something went wrong in the ICU. In addition, if you are reporting such data it can have unintended consequences, such as avoidance, where surgeons in wanting to keep their mortality down will avoid treating high-risk patients. As a surgeon, I understand that no one wants to be the outlier, but that's not behaviour we want to encourage. It's a really difficult balancing act between on the one hand, showing that we're getting good results and identifying the true outliers, and also not encouraging gaming behaviour because that's not good for anyone. Of course, we will continue to publish mortality data, but in the future there will also other outcome measures we can report.”

He discussed several outcome measures that BOMSS could report on but noted that data can  reveal strange anomalies. For example, one of the things they noted was patients who were operated on a Friday tend to have a longer stay than those operated Monday to Thursday. The most likely  reason is not because the patients were high-risk or had a complication, but because the on call surgical team were reluctant to discharge a bariatric patient over the weekend.

“We could also look at complication rates, but the problem with complication rates is that we rely on people to put the complications into the NBSR. However in the UK, bariatrics is often a supra-regional service; and hence patients in general do not come back to the bariatric unit when they have a complication, but instead tend to go to their local A&E department. If you look at the Hospital Episode Statistics (HES) data and look at re-admissions, it is significantly higher than those seen on NBSR - one reason is the bariatric surgical teams may not know patients have been re-admitted. Even if you ask patients at six weeks follow up if they have had any problems, sometimes they will forget  for example they spent the night in  A&E suffering from dehydration. Another issue is that HES data does not distinguish between a gastrectomy done for cancer and one for obesity, so this is another source of noise in the data.

NBSR changes

One aspect of the NBSR he is eager to strengthen is the number of private procedures that are collected on the database. Khan states "we know that about half of the half the bariatric surgery is now being done in the private sector; and post pandemic this figure is increasing. Some, but not all private centres do submit NBSR data so we need to find way to convince all surgeons and centres to collect and submit  all their data. The Department of Health have been very generous in giving BOMSS money for the publication of the NHS reports;  and individual NHS trust contribute to  the NBSR to allow us to analyse  data. What we need to do is find a similar  funding and resource structure which works in collaboration with the private sector.”

He revealed that the NBSR is currently undergoing a review with the plan to add several new procedures including endoscopic sleeve gastrectomy and Single Anastomosis Duodenal Switch, as well as adding a section within the database for revision surgery.

“To date we've taken the view that NBSR is purely a registry is for patients who are having surgery for weight loss.  If you have a sleeve and then have a bypass, we  collect data if the bypass is being done for weight regain, not for reflux. But that does not reflect what is actually happening in the real-world where an awful lot of revisional surgery is in fact being done for functional reasons. Under our current system it is very difficult to reflect these outcomes because our primary outcome has always been weight.”

As well as improvements to the NBSR, Khan would also like to see its data used in conjunction with other national database such as the National Obesity Audit, National Diabetes Audit and HES, to help answer one of the most important questions in bariatric surgery - not whether it works - but when should we intervene?

“Once you've got obesity-related complications, the risks of  surgery  increases.  An useful analogy can  be seen with aortic valve surgery -if  you were to ask  what is the optimum time to replace a stenotic valve then the answer would be day before your symptoms start. Well if we were to ask when the best time to do bariatric surgery it would be day before you get metabolic impairments. But of course, the problem is that we currently cannot predict  when in patient’s natural weight trajectory these metabolic impairments are about to develop. I believe data-mining from all these audits we could provide much needed answers to these questions”.

As an example, he cited the Second NBSR Report (2014) which showed that UK bariatric patients were heavier and  more unhealthy  as compared to other European  countries.  It would be much more cost-effective to operate on people who are younger, fitter and thinner, he argues, and that should be the future direction of research.

Bariatric tourism and emergencies

Perhaps one of the most pressing and interlinked issues in bariatric surgery is bariatric tourism and emergencies. A national multi-centre prospective audit of unplanned surgical and endoscopic interventions in patients who have undergone bariatric surgery in the UK or abroad - The National Emergency Bariatric Surgical Audit (NEBSA) – was recently established in the UK. Khan would like to try and link this database with the NBSR so patient’s complications and outcomes can be collected and reported on more thoroughly.

“This would be difficult to achieve, one that will require funding and ethical approval, but is one that is in keeping with our notion of getting not just good data on our own operations,  but excellent robust data for every  bariatric patient.”

The issue of bariatric tourism is, Khan believes, because the UK simply does not do enough bariatric procedures and he can understand the desperation of people seeking treatment abroad. “There's nothing wrong with medical tourism. I live  ten miles away from Great Ormond Street and people come from all over the world to have treatment there. That is an example of good medical tourism - ie informed patients going to a centre of excellence. What we're talking about here is a patient saying ‘it's going to cost too much money, so I'll go to the cheapest provider’ and, broadly speaking, you get what you pay for. There's some superb surgeons and centres in countries such as Turkey, but they charge more. But the centres who are charging say £3000 for bariatric surgery are not likely to provide the patient care that is required. And I think the big worry for me is that their business model is predicated on the NHS picking up their complications. That’s like buying a car without insurance.”

Khan and his team have previously reported that the costs from five London hospitals of treating complications from patients returning from having bariatric surgery abroad, could have funded over 150 bariatric surgical procedures in those five hospitals. So ultimately, correcting the mistakes of others is actually costing the NHS more than the actual surgery would have cost the NHS itself.

“Overall, as a society, we can be very, very proud of the NBSR. The past-President of BOMSS, Mr Vinod Menon, rightly said it is the ‘jewel on the crown’ of our society,” he concluded. “Now, I think we need to move to the next step, which is research and trying to collaborate with other databases to try and get a more global picture of obesity, as opposed to just obesity surgery.”


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