Unplanned interventions following bariatric surgery: first cohort outcomes from the National Emergency Bariatric Surgery Audit (NEBSA)

Abstract

Background:

Despite the increasing volume of bariatric surgery, patterns of management following complications are poorly characterized in national datasets. We present the UK data collected by the National Emergency Bariatric Surgery Audit on patient characteristics following treatment for bariatric surgery complications, concentrating on 30-day mortality, complication severity, threshold for intensive care unit (ITU)/ high dependency unit (HDU) care, and postoperative follow-up. These data seek to inform the design of new clinical studies, support service development, and address surgical training requirements.

Methods:

A prospective, multi-center audit was conducted across UK hospitals from October 2023 to March 2025. Adults presenting with bariatric surgery-related complications requiring urgent intervention were included. Demographics, index procedures, presentation details, and outcomes were collected using a standardized electronic tool.

Results:

A total of 187 patients were included. The median age was 43 years, and 85.6% were female. The most common index procedures were sleeve gastrectomy (25.7%) and Roux-en-Y gastric bypass (31%). A total of 34.8% of patients had undergone surgery abroad. Emergency department attendance accounted for 72.2% of presentations. Emergency surgery was needed in 86.1% of cases, with two recorded deaths (0.8%). Additionally, 14% of patients were admitted to ITU. Follow-up was arranged for 73.3% of patients. Variation was noted in follow-up plans and the threshold for ITU/HDU care.

Conclusion:

Emergency bariatric surgery is a distinct and growing domain within acute surgical practice. This study highlights the urgent need for standardization of treatment pathways, targeted investment, training, and national collaboration to improve outcomes in the emergency treatment of bariatric complications. The data from this cohort can provide a stepping stone to better understanding the service, training, research, and funding needs of complex bariatric emergency services.

Introduction

The landscape of bariatric surgery has evolved considerably over the past two decades. In the UK, this is reflected in increasing procedural volume and broader patient eligibility. Elective bariatric surgery is generally regarded as safe, with a mortality rate ranging from 0.03 to 0.2%, depending on the type of procedure carried out[1]. While the safety and efficacy of bariatric surgery in the elective setting are well established, the nature, frequency, and outcomes of emergency presentations remain poorly understood.

Complications may arise in the immediate or delayed postoperative periods, with early issues such as staple line and anastomotic leaks, bleeding, internal herniation, and bowel obstruction, and later sequelae including marginal ulcers and nutritional complications. These often require urgent surgical or endoscopic intervention[2]. More importantly, such events frequently occur outside the index surgical center, with patients presenting to non-specialist units, often influenced by factors such as insurance status or clinical urgency[3]. In the United Kingdom, national guidance recommends that patients experiencing complications should be referred to specialist bariatric centers[4]. Despite potentially longer travel distances, treatment at such centers has been associated with improved patient outcomes[5].

Elective bariatric surgery is effectively captured by the National Bariatric Surgery Registry (NBSR). These data also contribute to the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) registry report, hence having an international effort in capturing elective data[6]. Data from both NBSR and IFSO reports show that elective bariatric surgery is safe, with an in-hospital mortality rate of 0.04% and an overall complication rate of 2.4%[7] and it is cost-effective^[8,9^]. The main issue for UK bariatric services has been patient access to elective services, with long waiting times pushing patients to seek private treatment either within the country or abroad^[10–12^].

The number of private bariatric surgery procedures is recorded as being between 5000 and 6000 in the UK, with an additional estimated 10000 per year traveling abroad for weight loss surgery[13]. The emergency landscape, hence, remains poorly recorded, with great discrepancies between NBSR and Hospital Episode Statistics (HES) data[7]. These discrepancies relate to patients presenting to non-bariatric centers with no access to NBSR, hence leading to underreporting. Additionally, many patients who have had their procedures abroad present to National Health Service (NHS) hospitals, as their initial unit does not provide emergency cover[14].

These shifts, combined with varying patient adherence to structured NHS weight management pathways, present unique challenges to emergency service delivery, continuity of care, and accurate data collection and auditing[15]. The current provision of bariatric services – both NHS and private – is unlikely to meet future demand without substantial investment, and the cost of managing postoperative complications is considerable[16]. Notably, only one UK-based study has previously explored emergency bariatric activity, and it encompassed a period (2011–2013) during which service provision was markedly different from current practice[17].

We established the National Emergency Bariatric Surgical Audit (NEBSA) in recognition of the need for a national, prospective platform to capture and analyze emergency bariatric interventions. This multicenter initiative aimed to provide granular insight into real-world clinical practice, resource utilization, and patient outcomes following unplanned interventions for bariatric complications. This study presents the first cohort of patients recorded in the first 18 months of the NEBSA study, offering patient characteristics and a contemporary overview of emergency bariatric activity across the UK. By doing so, we aim to demonstrate the importance of accurate data collection through a dedicated system, which will act as a learning platform and identify areas for quality improvement, training, policy, and service improvement.

Methods

Study design and setting

This is a prospective, multicenter audit conducted across NHS and independent sector hospitals in the United Kingdom, managing emergency gastrointestinal and bariatric conditions. Participating sites included both specialist bariatric centers and non-bariatric acute surgical units. The audit was designed in accordance with SQUIRE 2.0 (Standards for Quality Improvement Reporting Excellence) guidelines and was locally registered as a clinical audit at each participating institution[18]. The detailed study protocol was published previously[19].

HIGHLIGHTS

• Emergency bariatric surgery represents a distinct and growing domain within acute surgical practice, with 86% of patients requiring emergency operative intervention and 14% needing intensive care admission.

• Over one-third of patients (34.8%) have their index bariatric procedure abroad, highlighting the substantial impact of medical tourism on National Health Service emergency services and the need for international care coordination.

• Significant variation exists in clinical pathways, including critical care thresholds and post-discharge follow-up arrangements (74%), emphasizing the urgent need for standardized national treatment protocols.

Patient selection

All patients who aged 18 years or older and had an emergency admission requiring intervention to diagnose or treat complications of bariatric surgery were included. This included presentations through emergency departments, urgent care, and transfers from other institutions, as well as returns to theater during the index admission. Procedures encompassed surgical, endoscopic, and radiological interventions. Exclusion criteria were limited to patients with hospital stays under 24 hours, misclassified readmissions unrelated to bariatric procedures, and patients under the age of 18.

Data collection and storage

Data were collected prospectively using a secure, bespoke electronic platform hosted by Bedfordshire Hospital NHS Foundation Trust. Contributors required NHS.net authentication with two-factor login. Data fields were standardized using structured inputs, with mandatory completion for key variables. Pseudo-anonymized patient data were validated locally prior to submission. Each participating site maintained oversight through clinical governance and Caldicott Guardian approvals. (The Caldicott Guardian is a senior healthcare professional who is responsible for protecting patient confidentiality and ensuring that data are used ethically and appropriately.)

Variables and outcomes

Collected data included patient demographics (age, sex, ethnicity), bariatric history (index procedure, surgical center, time since surgery), clinical presentation, diagnostic tests, and therapeutic interventions. The primary explored outcomes included 30-day mortality and complication severity classified using the Clavien–Dindo classification[20]. Secondary outcomes included variations in the need for critical care and postoperative follow-up.

Statistical analysis

Descriptive statistics were used to summarize demographic and clinical data. Categorical variables were compared using chi-squared or Fisher’s exact tests, and continuous data were analyzed with t-tests or Mann–Whitney U tests, as appropriate. Normality was assessed using the Shapiro–Wilk test. Multivariable regression was employed to explore predictors of adverse outcomes. A P-value of < 0.05 was considered statistically significant.

Results

Patient demographics and baseline characteristics

A total of 187 patients were included in this interim analysis. The vast majority were women (n = 160, 85.6%). The median age was 43 years (IQR: 35–52). Age was not recorded for 22 patients.

Patients were found to be predominantly of Caucasian/British/Irish ethnicity (n = 99; 65%), though ethnicity data were missing in 90 cases. Patients presented to 14 NHS trusts. Most of the data were collected from two bariatric units: Luton and Dunstable University Hospital (25%) and St Richard’s Hospital (15%). This is to be expected, as most bariatric emergency patients presenting to non-bariatric units would be transferred to specialist services.

One-third of patients (n = 50, 26.7%) had their index bariatric surgery at the same trust as their emergency presentation, while 34.8% (n = 65) had undergone surgery abroad. The remainder of the patients had their index procedure in other UK NHS hospitals (n = 62, 33.2%) or private UK hospitals (n = 10, 5.3%).

Index procedure

The most common index surgical procedure was Roux-en-Y gastric bypass (n = 58, 31%), followed by sleeve gastrectomy (n = 48, 25.7%). Gastric balloon procedures were carried out in 37 patients (19.8%). Other procedures included gastric band (n = 26, 13.9%) and one-anastomosis gastric bypass (n = 14, 7.5%). A full list of index procedures is shown in Table 1.

Table 1.

Data demographics, index operation, and interventions.

	n	%
Sex
Female	160	85.6
Male	27	14.4
Age (median)	43 (35–52)
BMI_Index_Operation (median/IQR)	39.9 (34.3–47.9)
BMI_Emergency_Presentation (median/IQR)	31.1 (26.6–38.8)
Time from index operation to emergency presentation (median/IQR)	5 (1–40)
Type_Of_Index_Operation
Duodenal switch	1	0.5
Gastric balloon	37	19.8
Gastric band	26	13.9
One-anastomosis gastric bypass (mini-bypass)	14	7.5
Roux-en-Y gastric bypass	58	31.0
Single-anastomosis stomach-ileal bypass with sleeve (SASI-S)	3	1.6
Sleeve gastrectomy	48	25.7
Site_Of_Bariatric_Surgery
Abroad	65	34.8
Other UK Hospital (NHS)	62	33.2
Other UK hospital (Private)	10	5.3
Same trust of admission	50	26.7
Mode_Of_Referrals
Another NHS trust	26	13.9
Clinic	3	1.6
Emergency department	135	72.2
General practitioner	12	6.4
Independent sector	5	2.7
Others	6	3.2
American_Society_Of_Anesthiology_Grade
I	11	5.9
II	69	36.9
III	92	49.2
IV	13	7.0
V	2	1.1
Mortality_At_Discharge
Alive at discharge	185	98.9
Deceased at discharge	2	1.1
Planned_Follow_Up
No	50	26.7
Yes	137	73.3
Emergency_Nutritional_Intervention
No	124	66.3
Yes	63	33.7
Type_Of_Emergency_Nutritional_Intervention
Combined	16	8.6
Enteral	29	15.5
No intervention	67	35.8
Oral	57	30.5
Parenteral	18	9.6

ASA classification at emergency presentation

ASA classification at the point of emergency presentation revealed that 49.2% (n = 92) of patients were ASA III, with 7% (n = 13) recorded as ASA IV and 1.1% (n = 2) as ASA V (Table 1).

Mode of referral

The most common route of presentation was through the emergency department (n = 135, 72.2%), followed by referrals from other NHS trusts (n = 26, 13.9%) and GPs (n = 12, 6.4%). A full list of modes of referral is shown in Table 1.

Presenting diagnosis

The most common presenting diagnoses were obstruction (n = 35, 18.6%), anastomotic leak (n = 26, 13.8%), and gastric balloon intolerance (n = 31, 16.5%). Other presenting diagnoses were malnutrition (n = 12, 6.4%), internal hernia (n = 10, 5.3%), and adhesional bowel obstruction (n = 10, 5.3%). Information on presenting diagnoses was missing in 48 records, and some patients had more than one diagnosis recorded (e.g., obstruction and internal hernia). A full list of presenting diagnoses is shown in Table 2 with a complete breakdown according to the index procedure. It is also important to note that the term “obstruction” was used as a generic term to describe obstruction from all etiologies.

Table 2.

Presenting diagnosis by index procedure.

	Type_Of_Index_Operation
	Duodenal switch		Gastric balloon		Gastric band		One-anastomosis gastric bypass (mini-bypass)		Roux-en-Y gastric bypass		Single-anastomosis stomach-ileal bypass with sleeve (SASI-S)		Sleeve gastrectomy		Total
	n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%
Leak	0	0.0	0	0.0	1	3.8	5	35.7	9	15.5	0	0.0	11	22.9	26	13.9
Bleed	0	0.0	0	0.0	0	0.0	2	14.3	2	3.4	1	33.3	8	16.7	13	7.0
Ulcer	0	0.0	0	0.0	1	3.8	2	14.3	8	13.8	1	33.3	1	2.1	13	7.0
Balloon_Intolerance	0	0.0	19	51.4	4	15.4	1	7.1	1	1.7	0	0.0	6	12.5	31	16.6
Stricture	0	0.0	0	0.0	0	0.0	2	14.3	4	6.9	1	33.3	8	16.7	15	8.0
Obstruction	1	100.0	4	10.8	2	7.7	4	28.6	14	24.1	2	66.7	8	16.7	35	18.7
Perforation	0	0.0	3	8.1	0	0.0	0	0.0	1	1.7	0	0.0	1	2.1	5	2.7
Displaced_Band	0	0.0	0	0.0	11	42.3	0	0.0	0	0.0	0	0.0	0	0.0	11	5.9
Balloon_Intolerance	0	0.0	31	16.60	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	31	16.6
Dysphagia	0	0.0	0	0.0	1	3.8	0	0.0	0	0.0	0	0.0	0	0.0	1	0.5
Internal_Hernia	0	0.0	0	0.0	0	0.0	0	0.0	9	15.5	1	33.3	0	0.0	10	5.3
Hiatus_Hernia	0	0.0	0	0.0	0	0.0	0	0.0	2	3.4	0	0.0	4	8.3	6	3.2
Malnutrition	0	0.0	0	0.0	0	0.0	2	14.3	2	3.4	0	0.0	8	16.7	12	6.4
Adhesion	0	0.0	0	0.0	2	7.7	1	7.1	7	12.1	0	0.0	0	0.0	10	5.3
Sleeve_Twist	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	3	6.3	3	1.6
Port_Site hernia	0	0.0	0	0.0	1	3.8	1	7.1	0	0.0	0	0.0	0	0.0	2	1.1
Fistula	0	0.0	0	0.0	1	3.8	1	7.1	0	0.0	0	0.0	0	0.0	2	1.1
Other	1	100.0	8	21.6	3	11.5	1	7.1	10	17.2	0	0.0	5	10.4	28	14.9

Clinical outcomes and interventions

From the 187 patients, 161 (86.1%) required emergency operative intervention. Planned follow-up was arranged for 74% of cases. Two patients died in-hospital, resulting in an all-cause mortality rate of 0.8%. According to the Clavien–Dindo classification, 63% of complications were classified as Grade III, while 12% were classified as Grade IV.

The most common surgical interventions carried out were laparoscopy, washout, and drain insertion (n = 40, 21.4%), followed by gastric band removal (n = 19, 10.2%), laparotomy (n = 16, 8.6%), and repair of internal hernia (n = 13, 7%). Endoscopic interventions were carried out in the form of stricture dilatation (n = 8, 4.3%) and gastric balloon removal (n = 31, 16.6%).

Emergency radiological interventions were reported in 1.1% (n = 2) of patients, primarily in the form of drain insertions. Table 3 shows the breakdown of the emergency interventions per index procedure.

Table 3.

Emergency treatment provided.

	Type_Of_Index_Operation
	Duodenal switch		Gastric balloon		Gastric band		One-anastomosis gastric bypass (mini-bypass)		Roux-en-Y gastric bypass		Single-anastomosis stomach-ileal bypass with sleeve (SASI-S)		Sleeve gastrectomy
	n	%	n	%	n	%	n	%	n	%	n	%	N	%
Conversion	0	0.0	0	0.0	0	0.0	1	7.1	0	0.0	1	33.3	9	18.8
Perforation_Repair	0	0.0	1	2.7	1	3.8	3	21.4	5	8.6	1	33.3	2	4.2
Adhesiolysis	0	0.0	0	0.0	1	3.8	2	14.3	8	13.8	1	33.3	2	4.2
Repair internal hernia	0	0.0	0	0.0	0	0.0	0	0.0	9	15.5	1	33.3	3	6.3
Repair port site hernia	0	0.0	0	0.0	0	0.0	0	0.0	1	1.7	0	0.0	0	0.0
Band removal	0	0.0	0	0.0	19	#####	0	0.0	0	0.0	0	0.0	0	0.0
Balloon removal	0	0.0	31	16.6	0	0.0	0	0.0	0	0.0	0	0.0	31	16.6
Revision anastomosis	1	100.0	0	0.0	0	0.0	2	14.3	9	15.5	0	0.0	0	0.0
Stricture dilatation	0	0.0	0	0.0	0	0.0	2	14.3	3	5.2	0	0.0	3	6.3
Stent	0	0.0	0	0.0	0	0.0	2	14.3	2	3.4	0	0.0	5	10.4
Washout	0	0.0	1	2.7	2	7.7	6	42.9	14	24.1	2	66.7	15	31.3
Drain	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	2	4.2
Feeding	0	0.0	0	0.0	1	3.8	2	14.3	6	10.3	2	66.7	9	18.8
Laparotomy	0	0.0	1	2.7	1	3.8	0	0.0	9	15.5	1	33.3	4	8.3
Other	0	0.0	0	0.0	0	0.0	0	0.0	1	1.7	0	0.0	2	4.2

Critical care utilization

In 14% of patients, admission to an intensive care unit was required, with a further 5.5% requiring HDU care.

Follow-up care

Follow-up plans were recorded in 74% of patients. Notably, some patients would not require follow-up (e.g., post-gastric balloon removal); however, clearer data recording is required in this regard. Some of the differences are expected to relate to a lack of uniformity between ICBs (Integrated Care Boards) in funding pathways for emergency bariatric patients.

Discussion

This prospective national audit offers a novel and systematic insight into emergency presentations following bariatric surgery in the United Kingdom. The data highlight a substantial and complex clinical workload, with patients requiring operative intervention and critical care input. These results reinforce the hypothesis posed in the original NEBSA protocol[19] that the impact of emergency bariatric surgery is under-recognized and inconsistently managed within current NHS pathways. This inconsistency results from multiple variables, both local and national. At a national level, recognized differences exist between integrated care boards with regard to funding pathways and national pay tariffs. At a more local level, differences exist between NHS trusts with regard to the availability of intensive care unit / high dependency unit beds in the postoperative period, local care protocols, and the availability of specialized bariatric care.

Additionally, this work recognizes the impact of emergency bariatric surgery within NHS services and quantifies the need for better planning, resource utilization, and staff training.

Most patients presented via the emergency department, often to non-specialist centers, with only one in three returning to their original surgical unit. This dispersion of care adds to the clinical complexity, as local teams may lack detailed operative records, nutritional surveillance data, or specialist bariatric input. Bariatric services are centralized into tertiary units in the UK and worldwide. This leads to specialization of services in the management of this patient group. This centralization, however, does not necessarily occur in emergency bariatric surgery, leading to difficulties in the management of these patients by non-specialist units. We would argue that all patients with complications post-bariatric surgery should be managed in specialized units. The findings support the protocol’s initial rationale[21] for developing a unified platform to capture granular, real-time data from a wide range of providers.

Notably, 34.8% of patients had undergone surgery abroad, underscoring the ongoing challenge of managing complications associated with bariatric medical tourism. This figure highlights the need for greater transparency and information-sharing across international bariatric services. This practice, driven by shorter waiting times, lower costs, and the increasing availability of surgical packages overseas, presents several clinical and governance challenges to NHS services. Patients returning to the UK often present acutely with complications such as leaks, internal herniation, or obstruction – without operative records, clear discharge instructions, or structured follow-up plans. This lack of continuity significantly hampers clinical decision-making and may delay diagnosis or appropriate intervention[22].

BOMSS (British Obesity and Metabolic Surgery Society) has raised many concerns regarding bariatric tourism, particularly in relation to inadequate preoperative assessment and counseling, poor choice of procedures offered, and the unknown quality and safety of the team providing surgery. Furthermore, the risk of long-distance travel immediately after surgery, with increased risks of venous thromboembolism, needs to be taken into account. Patients undergoing bariatric surgery abroad are also less likely to have routine follow-up after their surgery, leading to a lack of direct access to specialist services and a greater possibility of nutritional deficiencies[23]. Other authors have called for the creation of an international registry of accredited bariatric tourism providers to aid patients in the decision-making process[24].

The absence of standardized protocols, variable quality assurance mechanisms, and unclear access to multidisciplinary follow-up in overseas centers may contribute to avoidable morbidity. While patients have the right to seek treatment abroad, the NHS inevitably absorbs the impact of managing complications – often without adequate preparation or reimbursement structures. This raises important questions around policy, consent, and patient education. National guidance on pre-travel counseling, shared documentation standards, and perhaps a formal registry for repatriated bariatric cases could enhance both safety and service planning. Future iterations of NEBSA may consider capturing more granular data on the country of origin, perioperative procedure, and timeline to better inform system-wide responses to this expanding phenomenon.

Clinical outcomes from NEBSA increase awareness of these issues with supporting real-life data. Over 80% of patients required emergency surgery, and 14% required admission to intensive care. The in-hospital mortality rate, while low at 0.8%, must be viewed in the context of significant missing data, especially regarding ASA scores and Clavien–Dindo grading. Over 60% of patients experienced Clavien–Dindo Grade III or higher complications, reinforcing the argument that emergency bariatric surgery demands highly trained personnel and robust escalation pathways. These results mirror prior international registry studies, which have similarly demonstrated elevated complication rates associated with revisional or emergency procedures^[25,26^]. Data on revisional and emergency bariatric procedures on an international scale are often fragmented with missing aspects, a phenomenon which is recognized by IFSO[26].

Importantly, this initial report has exposed variation in the delivery of follow-up care. Only 74% of patients had documented plans for post-discharge monitoring by an NHS bariatric unit. While not all patients require regular follow-up, the process may be inhibited by differences in funding between regions.

This underscores the need for shared care pathways and integrated electronic health records. The creation of such frameworks would help to ensure longitudinal continuity, support early detection of late complications, and facilitate patient engagement. Lessons can be learnt from the introduction of other emergency databases, such as National Emergency Laparotomy Audit, which raised issues regarding care, redefined best practices, and has led to improvements in patient outcomes through standardization of care^[27,28^].

Conclusions

In conclusion, the NEBSA interim findings underscore the pressing need to recognize emergency bariatric surgery as a distinct and growing domain of acute surgical practice. These data highlight the need for a national collaboration to establish a standardized treatment pathway for emergency bariatric patients based on data. Additionally, aspects such as targeted investment in workforce training, resource funding and appropriate utilization, cross-sector communication, and long-term outcome monitoring are essential to this process. National and international bariatric registries can utilize the NEBSA framework to measure the need for emergency bariatric services worldwide and facilitate healthcare resource utilization and planning.

Study strengths and limitations

The strengths of this study include its prospective design, multi-institutional reach, and emphasis on standardized data collection. The NEBSA platform, although still young, has successfully demonstrated that national collaboration in emergency bariatric care is feasible, even in the absence of centralized funding. However, several limitations must be acknowledged. The sample size remains modest relative to the national impact, and case ascertainment may be biased toward centers with established bariatric interest. Furthermore, substantial missing data in several fields, including ethnicity, diagnosis, and follow-up, suggest that further refinements to the data entry interface and training materials are warranted. These aspects are expected to improve in the future as the database matures and a greater awareness of its role becomes more prominent.

Future work

Future directions include the formal linkage of NEBSA records to HES and NBSR datasets, the development of benchmarking dashboards, and the structured dissemination of findings to NHS England, the Royal College of Surgeons, BOMSS, and IFSO. Further engagement with frontline clinicians is essential to increase case capture and enhance real-world applicability. Future work will aim to involve patient representatives as essential stakeholders in bariatric surgery services.

Ethical approval

The project has been registered as an audit individually by all contributing trusts. No patient identifiable information is presented in this manuscript. No further ethical approval was required for the purpose of this manuscript.

Consent

None required.

Sources of funding

None.

Author contributions

A.T. wrote and amended the manuscript and is part of leading group for NEBSA collaboration, F.I. contributed to the initial manuscript data, A.A., O.A., M.A. and A.M. contributed to the data collection, analysis and concept for the manuscript. They are also senior leads for the NEBSA. M.L., M.H., R.Z., D.P. and G.R. reviewed and contributed to amendments required for the manuscript.

Conflicts of interest disclosure

None.

Research registration unique identifying number (UIN)

Not applicable.

Guarantor

Mohamed Aly.

Provenance and peer review

The data presented in this manuscript belongs to the NEBSA research group and governed by NHS GDPR. The manuscript has been peer reviewed and approved by all members of NEBSA collaborative group.

Data availability statement

All publicly available data are presented in Tables 1–4. The original data contain patient information and cannot be made publicly available.

Assistance with the study

We acknowledge the assistance of the NEBSA Collaborative Group in the conduct of this study.

Financial Support

None.

Presentation

Part of the data presented here were shared at the AUGIS conference to raise awareness of NEBSA.