NELA Data Requests and Collaborations

The aim of NELA is to provide high quality comparative data from all providers of emergency laparotomy to facilitate improvements in care for patients. Although NELA is run by the Royal College of Anaesthetists, we also work in conjunction with the surgical Royal Colleges and specialty organisations in addition to collaborating with other projects and key stakeholders.

If you are interested in making a data access request please read below on this webpage.

Accessing NELA Data

The NELA team are keen for NELA data to be used to maximal patient benefit. Thus, in addition to formal outputs by the central Project Team in the form of annual reports and dashboards, we actively encourage and support external proposals for secondary uses.
It is essential that the anonymity of the people included in the database is protected and that the data are used in an ethical way. We therefore provide two types of data from NELA:

1. Aggregate data

These are data at the level of an individual hospital. NELA already openly publish a large amount of data at aggregate levels and so these data do not need to be requested. Local users may access NELA data for their own hospital here.

However, for aggregate data that is not already published by the central NELA team, researchers will need to fill in the "Aggregate data request form" below. This might, for example, be for aggregate data on individual patient risk factors (e.g. the proportion of patients who are anaemic before surgery).

NELA grant permission for access to this type of data. Aggregate data can normally be emailed as an Excel file to an NHS or University email address. Please download the application form:

Download aggregate data request form

2. Patient level data

Individual, patient-level data is also available to external researchers following an application process. As NELA's funder and data controller, the Healthcare Quality Improvement Partnership (HQIP) must review and approve all requests for patient level data. We therefore ask that you complete NELA's data enquiry form (Form A) and HQIP's Data Access Request Form (DARF) as part of your application. Before applying, please first read HQIP's guidance which can be found on their website:

For more information on data sharing for uses outside of the NELA programme, please see

To receive patient level data, you are likely to need a recognised data safe haven that complies with certain IG standards.

Download application forms

The NELA team will review your application in the first instance and may request further information. Once approved, the NELA team will forward your DARF on to HQIP for consideration by the Data Access Request Group (DARG). DARG meet once every month to consider applications. More information about this process can be found here.

If approved, HQIP will inform NELA who will make arrangements to transfer the data to your secure data safe haven.

You should be aware that if your application is approved, there may be fees associated with the sharing of data for both NELA and HQIP. NELA's cost recovery policy can be found below.

Notes Regarding Mortality Data
The NELA dataset includes data on inpatient mortality. This can be provided under either of the above requests. If you require any other mortality data, you will need to make a separate data application via NHS Digital to request ONS date of death alongside a DARF. Although NELA obtains ONS date of death for its annual reports, we are legally unable to share on date of death that is directly taken or derived from ONS mortality (ie date of death, or alive/dead at 30 days).

Publications Resulting from Use of NELA Data

Collaborations and requests for NELA data have resulted in the following peer-reviewed publications. If you'd like more information about projects that NELA has collaborated with, please email us at

  • Boyd-Carson, H., Shah, A., Sugavanam, A., Reid, J., Stanworth, S.J. and Oliver, C.M. (2020), The association of pre-operative anaemia with morbidity and mortality after emergency laparotomy. Anaesthesia, 75: 904-912.

  • Boyd-Carson H, Doleman B, Cromwell D, Lockwood S, Williams JP, Tierney GM, Lund JN, Anderson ID; National Emergency Laparotomy Audit Collaboration. Delay in Source Control in Perforated Peptic Ulcer Leads to 6% Increased Risk of Death Per Hour: A Nationwide Cohort Study. World J Surg. 2020 Mar;44(3):869-875. doi: 10.1007/s00268-019-05254-x. PMID: 31664496.

  • Boyd-Carson H, Doleman B, Herrod PJJ, Anderson ID, Williams JP, Lund JN, Tierney GM; NELA Collaboration. Association between surgeon special interest and mortality after emergency laparotomy. Br J Surg. 2019 Jun;106(7):940-948. doi: 10.1002/bjs.11146. Epub 2019 Apr 25. Erratum in: Br J Surg. 2019 Sep;106(10):1403. PMID: 31021420.

  • Boyd-Carson H, Doleman B, Lockwood S, Williams JP, Tierney GM, Lund JN; National Emergency Laparotomy Audit Collaboration. Trainee-led emergency laparotomy operating. Br J Surg. 2020 Sep;107(10):1289-1298. doi: 10.1002/bjs.11611. Epub 2020 Apr 26. PMID: 32335905.

  • Coe PO, Lee MJ, Boyd-Carson H, Lockwood S, Saha A. Open Versus Laparoscopic Repair of Perforated Peptic Ulcer Disease: A Propensity-matched Study of the National Emergency Laparotomy Audit. Ann Surg. 2020 Nov 12. doi: 10.1097/SLA.0000000000004332. Epub ahead of print. PMID: 33201117.

  • Salih T, Martin P, Poulton T, Oliver CM, Bassett MG, Moonesinghe SR; NELA Project Team. Distance travelled to hospital for emergency laparotomy and the effect of travel time on mortality: cohort study. BMJ Qual Saf. 2020 Jun 23:bmjqs-2019-010747. doi: 10.1136/bmjqs-2019-010747. Epub ahead of print. PMID: 32576606.

  • Aitken RM, Partridge JSL, Oliver CM, Murray D, Hare S, Lockwood S, Beckley-Hoelscher N, Dhesi JK. Older patients undergoing emergency laparotomy: observations from the National Emergency Laparotomy Audit (NELA) years 1-4. Age Ageing. 2020 Jul 1;49(4):656-663. doi: 10.1093/ageing/afaa075. PMID: 32484859.

  • Pucher PH, Mackenzie H, Tucker V, Mercer SJ. A national propensity score-matched analysis of emergency laparoscopic versus open abdominal surgery. Br J Surg. 2021 Mar 16:znab048. doi: 10.1093/bjs/znab048. Epub ahead of print. PMID: 33724351.

  • Aggarwal G, Peden CJ, Mohammed MA, Pullyblank A, Williams B, Stephens T, Kellett S, Kirkby-Bott J, Quiney N; Emergency Laparotomy Collaborative. Evaluation of the Collaborative Use of an Evidence-Based Care Bundle in Emergency Laparotomy. JAMA Surg. 2019 May 1;154(5):e190145. doi: 10.1001/jamasurg.2019.0145. Epub 2019 May 15. PMID: 30892581; PMCID: PMC6537778.

  • Stephens TJ, Peden CJ, Haines R, Grocott MPW, Murray D, Cromwell D, Johnston C, Hare S, Lourtie J, Drake S, Martin GP, Pearse RM; Enhanced Perioperative Care for High-risk patients (EPOCH) trial group. Hospital-level evaluation of the effect of a national quality improvement programme: time-series analysis of registry data. BMJ Qual Saf. 2020 Aug;29(8):623-635. doi: 10.1136/bmjqs-2019-009537. Epub 2019 Sep 12. PMID: 31515437.

  • Stephens, T.J., Peden, C.J., Pearse, R.M. et al. Improving care at scale: process evaluation of a multi-component quality improvement intervention to reduce mortality after emergency abdominal surgery (EPOCH trial). Implementation Sci 13, 142 (2018).

  • Peden CJ, Stephens T, Martin G, Kahan BC, Thomson A, Rivett K, Wells D, Richardson G, Kerry S, Bion J, Pearse RM; Enhanced Peri-Operative Care for High-risk patients (EPOCH) trial group. Effectiveness of a national quality improvement programme to improve survival after emergency abdominal surgery (EPOCH): a stepped-wedge cluster-randomised trial. Lancet. 2019 Jun 1;393(10187):2213-2221. doi: 10.1016/S0140-6736(18)32521-2. Epub 2019 Apr 25. PMID: 31030986.

  • Peden CJ, Stephens T, Martin G, Kahan BC, Thomson A, Everingham K, Kocman D, Lourtie J, Drake S, Girling A, Lilford R, Rivett K, Wells D, Mahajan R, Holt P, Yang F, Walker S, Richardson G, Kerry S, Anderson I, Murray D, Cromwell D, Phull M, Grocott MPW, Bion J, Pearse RM; the EPOCH trial group. A national quality improvement programme to improve survival after emergency abdominal surgery: the EPOCH stepped-wedge cluster RCT. Southampton (UK): NIHR Journals Library; 2019 Sep. PMID: 31577397

  • Eugene N, Oliver CM, Bassett MG, Poulton TE, Kuryba A, Johnston C, Anderson ID, Moonesinghe SR, Grocott MP, Murray DM, Cromwell DA, Walker K; NELA collaboration. Development and internal validation of a novel risk adjustment model for adult patients undergoing emergency laparotomy surgery: the National Emergency Laparotomy Audit risk model. Br J Anaesth. 2018 Oct;121(4):739-748. doi: 10.1016/j.bja.2018.06.026. Epub 2018 Aug 23. PMID: 30236236.

Frequently Asked Questions

Please see the below Frequently Asked Questions for data requests

Can I use NELA data for quality improvement projects or evaluations?

Yes. Individual teams have access to the data that they have uploaded. Aggregate data is available for all teams participating in NELA and can be downloaded from our website or from
All requests for anonymous patient level data need to go through the application and approvals process.

Do I need to inform NELA if I use aggregate data for quality improvement projects or research?

No. However, NELA must be attributed as the source of the data in publications or reports. We are also keen to hear about any quality improvement projects using NELA data and may be able to help you share and showcase your work. Please let us know how you are using the data to improve care by emailing us at or telephoning the NELA helpdesk 020 7092 1683 / 1676

How do I attribute NELA in publications or reports?

Please attribute NELA as 'The National Emergency Laparotomy Audit (NELA), Royal College of Anaesthetists'. When describing funding please include the following statement 'NELA was commissioned by the Healthcare Quality Improvement Partnership (HQIP), funded by NHS England and Welsh Government and it is part of the National Clinical Audit and Patient Outcomes Programme (NCAPOP).' Additional information about authorship is provided here:

How do I request anonymous patient level data?

The first step is to complete a NELA patient-level data enquiry form detailing your proposal; this will be reviewed by the NELA Project team at their monthly meeting. The team will then respond to say whether the application is suitable or not, or if further information is required. In all cases, accepted proposals will then need approval by the Data Access Request Group (DARG), hosted by the Healthcare Quality Improvement Partnership (HQIP), the commissioners and data controllers of NELA. Successful applications to the DARG will then require a data sharing agreement to be signed before data can be released. In some cases, application may also need to be made to NHS Digital.

Can I request patient level data that includes patient identifiers?


Can I request data that is not already in the public domain?

Yes. If you require aggregate anonymous data that is not already available freely then please fill out the form which is available in our Data Requests page. We may be able to provide bespoke extracts of aggregate data, depending on the details of the request and the data analysis capacity of the NELA team. We are unlikely to be able to provide access to data that has yet to be published in any forthcoming NELA annual report.

Can I collaborate with the NELA team on a project or proposal?

Yes, NELA has already collaborated with research teams on the EPOCH, EL Collaborative and ALPINE projects. Every approach for collaboration will be considered by the NELA team, and the decision on whether this can proceed will depend on the nature of the project and the capacity of the NELA team. If you wish to collaborate with the NELA team then please contact us to discuss. Additional information about authorship is provided here:

Is there a cost to requesting data?

Aggregate NELA data is published openly and freely, and there is no charge for downloading or using aggregate data.

Charges may apply for new aggregate data, and extracts of anonymous patient level data. The charges are to recover the costs of managing the applications process and preparing extracts of data. The costs are likely to depend on the level of service required from NELA, and will depend on whether this is limited to a simple extract of data, or requires additional input such as methodological or statistical support. We will be able to advise on costs once your completed application form is received.

Will you let me know if someone else is carrying out a similar study?

Because aggregate data are open access, it is unlikely that we will know about studies using aggregate data and therefore will not be able to tell you if you are duplicating a study. You should consult the NELA team in the first instance.

Can I use extracts of anonymous patient level data for other studies?

No. Data can only be used in the manner described in the agreed research protocol. If you wish to carry out further studies not specified in the protocol then approval will need to be granted by the NELA team and the DARG at HQIP.

How long can I keep data?

There are no restrictions on keeping aggregate data.
However, extracts of patient level data must be securely destroyed after an agreed time specified in your DARF. Applicants should formally inform NELA and HQIP once data have been securely destroyed.

What about publishing my findings?

We expect that all studies using patient level data will be written up and published in a peer-reviewed publication. This is true even for 'negative' studies as the risk of publication bias from observational studies is even greater than for interventional studies. Wherever possible publications should be Open Access and researchers should include the costs of open access publication in funding applications for studies using NELA data. All studies using patient level data must be notified to HQIP in advance of publication.

How long will it take for my application to be reviewed?

NELA meetings are generally held monthly and applications are reviewed within these meetings. More complex applications may need discussion at more than one meeting. Therefore the minimum timescale before receiving a reply is likely to be one month, but the process may take longer for more complex applications.

What is the legal basis that NELA uses to process personal information?

Under GDPR the following legal bases apply: processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the controller (Article 6 (1) (e and (Article 9 (2)(i processing is necessary for reasons of public interest in the area of public health, such as protecting against serious cross-border threats to health or ensuring high standards of quality and safety of health care and of medicinal products or medical devices, on the basis of Union or Member State law which provides for suitable and specific measures to safeguard the rights and freedoms of the data subject, in particular professional secrecy.

Under the Common Law Duty of Confidentiality (CLDC), NELA uses Section 251 as its legal basis to meet the CLDC. You can find out more about CLDC here:

NELA currently has approval under Section 251 to collect patient level data (reference number: CAG 5-07(d)/2013) for all emergency laparotomy patients admitted to hospital

Historical Membership of the NELA Project Team

The document below contains an historical list of all members of the NELA Project Team: