NHS Digital Data Release Register - reformatted

Keele University projects

55 data files in total were disseminated unsafely (information about files used safely is missing for TRE/"system access" projects).

REadmissions, Adverse Complications and ouTcomes following Acute Myocardial Infarction Study — DARS-NIC-306651-W7L4C

Opt outs honoured: Yes (Excuses: Section 251 NHS Act 2006)

Legal basis: Health and Social Care Act 2012 - s261 - 'Other dissemination of information', National Health Service Act 2006 - s251 - 'Control of patient information'.,

Purposes: No (Academic)

Sensitive: Sensitive, and Non-Sensitive

When:DSA runs 2021-05 – 2024-05 2021.09 — 2025.02.

Access method: One-Off

Data-controller type: KEELE UNIVERSITY

Sublicensing allowed: No

Datasets:

  1. Civil Registration (Deaths) - Secondary Care Cut
  2. HES:Civil Registration (Deaths) bridge
  3. Hospital Episode Statistics Admitted Patient Care
  4. Civil Registrations of Death - Secondary Care Cut
  5. Hospital Episode Statistics Admitted Patient Care (HES APC)
  6. Civil Registrations of Death
  7. HES-ID to MPS-ID HES Admitted Patient Care

Type of data: Anonymised - ICO Code Compliant

Expected Benefits:

The findings of the REACT-AMI study could greatly improve local and national protocols of care provision for patients admitted with heart attacks. The benefit to patients and the public could be significant in several ways. Characterisation and developing a greater understanding of the prevalence, predictors and impact of the complications that occur following heart attack nationally is important, particularly to both patients and the wider NHS, given such complications have a significant impact on patient care and outcomes both in the short term and the long term. The development of new risk scores could facilitate clinicians in tailoring the treatment of patients according to the predicted risk. This is likely to confer benefits to patients presenting to hospitals with a heart attack as well as the treating physicians by improving risk stratification, balancing the risk and benefits of modern treatments of heart attack, identifying patients at risk of future complications, and guiding patient care provision to reduce the risk of repeat hospital admissions. Such risk scores may also form the basis of national reporting for benchmarking services, allowing expected risk-adjusted rates to be calculated.

All of the study findings will be reported to NICOR on an annual basis. NICOR are responsible for policy design and audit of care for patients admitted with heart attacks nationally. The risk stratification and other relevant findings such as causes of readmissions are expected to help policy-makers to implement measures to reduce the burden of readmission rates in this population. It is hoped that this will result in significant cost savings to the NHS by reducing the number of attendances to 'accident and emergency' and hospital admissions. For example, previous research work in the UK illustrates that unplanned readmissions occur in 9% of patients following a heart attack. It is therefore important to define the size of the problem in the UK, where cost and additional bed days are likely to be substantial in an overstretched National Health System. This might also allow policy makers to develop interventions to optimise care of these patients during index admission and implement pathways to reduce burden of re-admissions. From the patient point of view, it will be important for the patients to understand how different complications can affect their outcomes. This is hoped to help inform decision making when choosing between different treatment options. Furthermore, increased awareness in patients with heart attack may enable them to seek more appropriate medical care regarding minor and major complications post discharge.

Keele University's work are expected to provide important information relating to real-world outcomes, provide new information regarding optimal strategies to reduce the burden of complications, compare newer treatments/ strategies in the care provision of this cohort, particularly in areas/ patient groups where randomised controlled trials have not been undertaken. Publication of these findings in the academic journals/ international conferences are hoped to guide future research in this area such as those evaluating potent blood thinner medications, stents and procedural techniques to improve patient outcomes. For example, previous research work has demonstrated that bleeding complications and repeated heart attacks remain one of the most frequent adverse events after the index episodes. This programme of work will quantify the true extent of this problem in the UK population but will also compare different treatments which can potentially improve the care provision of these patients. Finally, this research will study patients’ outcomes who are otherwise not included in randomised control trials, such as those with different types of cancers, mental health conditions and other important comorbidities.

Outputs:

The study chief investigator is the deputy national audit lead for the National Institute for Cardiovascular Outcomes Research (NICOR) British Cardiac Intervention society. He is also a member of the NCAP (National Cardiovascular Audit Project) Operational and Methodology Group within NICOR. The findings of the study would be shared with the other audit leads, and if rates of unplanned readmissions were found to be significantly different between hospitals/ strategic health authority regions and the development of the risk score were to be successful, this would be implemented into national reporting by the group.

The main research findings will be presented on the Keele University webpages for the Keele Cardiovascular Research Group and the school of primary, social and community care in the form of news articles and press releases. Further dissemination of results and findings will be done via multiple sources such as Twitter, press releases, patient and public involvement (PPI) groups, particularly the patients representative groups that are part of the NICOR NCAP Operational and Methodology Group meetings that are held monthly, and national and international conferences and presentations. Furthermore, this work will be submitted for publications in peer-reviewed Journals soon after the analyses are completed.

Keele University will submit the findings of this study for presentation at the European Society of Cardiology, British Cardiovascular Society and American College of Cardiology annual meetings. The target scientific journals for this work will be Journal of American Medical Association (JAMA) Family, British Medical Journal, the Journal of the American College of Cardiology, and the American Heart Association Journal. All dissemination of data and results in relation to this project will be made in line with HES analysis guidance, aggregated with small numbers under 7 suppressed. The initial paper will be submitted for publication within the first 18 months of the project start date.

Processing:

Data flow:

Barts Health NHS Trust, on behalf of the National Institute for Cardiovascular Outcomes Research (NICOR), will submit patient identifiers from the Myocardial Ischaemia National Audit Project (MINAP) to NHS Digital as follows: NHS number, study ID, date of birth, postcode and gender. Date of index acute myocardial infarction (AMI) admission will also be supplied.

NHS Digital will return Hospital Episode Statistics (HES) Admitted Patient Care (APC), and Civil Registrations (Deaths) Secondary Care Cut data to the Barts Health NHS Trust pseudonymised by study ID.

NICOR has designed security mechanisms that allow only authorised users to access information on the NICOR data collection and reporting system. Each audit database is accessed through a secure ID, the ID can be set to expire or have its access terminated, preventing unauthorised users from accessing the system. A complex password is required to access the ID and the password can be set to expire after a given period, forcing the user to change it regularly. Access to the database is controlled by a database Access Control List (ACL). This records when users have accessed data. Users and organisations only have access to their own records. All system database accesses are recorded in a system log file that can be audited in the event of suspected security threats or data misuse. The information recorded and managed by NICOR about patients and the clinical care they have received is confidential. Strict security measures are in place to safeguard patient information.

The NICOR data management team (DMT) at Barts Health NHS Trust will link the HES APC and mortality data from NHS Digital with the associated clinical information from MINAP using the pseudonymised study ID number which cannot be used by Keele University to re-identify patients. The NICOR DMT are substantive employees of Barts Health NHS Trust and are appropriately trained in data protection and confidentiality. The NICOR DMT will check the linked dataset for completeness, accuracy and consistency, and modify ‘date of death’ to ‘the number of days living since index admission’ and a yes/ no mortality status. This will further mitigate any risk of patient reidentification by Keele University. The pseudonymised linked clinical database will then be transferred to Keele University. There will be no further onward flows of record-level data. NICOR will retain record level NHS Digital data for a maximum of 12 months following linkage to the relevant MINAP clinical information. NICOR will retain record level data for this time in case there is any loss of data or in accuracies in final merged data extract. This will provide Keele University the opportunity to request a correction of the data in order that all necessary analyses can be undertaken.

The data will be stored on the Keele University computer system with access restricted to substantive employees of Keele University for the purposes of the proposed project. There will be no requirement or attempt to re-identify individuals. Access to the Keele University computing resources is controlled by the University's Microsoft Active Directory through login IDs and passwords. Access to information assets is authorised by the Responsible Owner of the asset (the Information Guardian) and is granted by the Information Governance Lead (the Data Custodian). All information assets require a credential check on log in. All staff are fully trained in dealing with sensitive and confidential data, including their responsibilities to maintain patient confidentiality. Remote access to data is only allowed via a university secured laptop system via a secure VPN connection which is further protected by a secure authenticator password.

The data will be analysed by the REACT-AMI study team at Keele University. Exploratory analyses will quantify post-discharge complications, causes, and how these differ over baseline patient characteristics, types of heart attacks and time. The frequency of different types of complications, changes in frequency over time and association between different patient and hospital-related factors will be studied. All results will be produced at an aggregated level rather than at the patient level. A statistical risk assessment will be completed for each publication of data and small number suppression techniques in line with the HES Analysis Guide will be used to ensure that analysis is not disclosive.

BISTRO Trial application for NHS Digital data for data linkage — DARS-NIC-90126-D4Z2W

Opt outs honoured: No (Excuses: Mixture of confidential data flow(s) with consent and non-confidential data flow(s))

Legal basis: Health and Social Care Act 2012 - s261 - 'Other dissemination of information'

Purposes: No (Academic)

Sensitive: Sensitive, and Non-Sensitive

When:DSA runs 2021-07 – 2024-07 2022.06 — 2022.06.

Access method: One-Off

Data-controller type: KEELE UNIVERSITY

Sublicensing allowed: No

Datasets:

  1. Civil Registration (Deaths) - Secondary Care Cut
  2. HES:Civil Registration (Deaths) bridge
  3. Hospital Episode Statistics Admitted Patient Care
  4. Hospital Episode Statistics Critical Care
  5. Hospital Episode Statistics Outpatients
  6. Civil Registrations of Death - Secondary Care Cut
  7. Hospital Episode Statistics Admitted Patient Care (HES APC)
  8. Hospital Episode Statistics Critical Care (HES Critical Care)
  9. Hospital Episode Statistics Outpatients (HES OP)

Type of data: Anonymised - ICO Code Compliant

Objectives:

The "BioImpedance (BI) Spectroscopy To maintain Renal Output" - the BISTRO Trial - is a randomised controlled trial funded by the National Institute for Health Research (NIHR), the research funding arm of the NHS.

Most patients who develop kidney failure choose unit-based haemodialysis treatment. Dialysis removes waste products and excess fluid from the blood when the kidneys stop working properly. Haemodialysis involves diverting blood to a machine to be cleaned.

One of the main functions of dialysis is to control the amount of fluid in the body. Too much fluid can lead to raised blood pressure that damages the heart and increases the risk of stroke, and may cause fluid to collect in the lungs leading to breathing difficulties. Too little fluid causes dehydration, cramps and low blood pressure and more rapid or complete loss of any remaining kidney function. Bioimpedance (BI) is a simple, bedside measurement giving information about body composition, specifically how much excess fluid is present. Clinicians can use this to guide how much fluid should be removed from the body with the normal clinical assessment of the amount of fluid in the body, but it is not known if this results in better decisions and outcomes for patients.

This trial aims to test whether taking regular measurements with a bioimpedance device, which gives information about body composition, improves outcomes for people who have newly started haemodialysis treatment for kidney failure. In particular, the trial aims to see if this helps patients maintain their remaining kidney function, as this is associated with improved survival, fewer symptoms of kidney failure, fewer side effects of dialysis treatment and a better quality of life including confidence in managing their health, and cost benefit analysis.

People starting haemodialysis as an outpatient with some remaining kidney function were invited to participate in a clinical trial that compares current best practice with the same but additionally guided by regular bioimpedance measurements. The study has randomised 438 consented patients from about 34 dialysis units across the UK. This agreement refers to the 381 consented individuals from England only.

Patients that have given their informed consent were randomly allocated into two study groups. Other than allocation of the intervention under investigation (which participants have given informed consent to be allocated through randomisation), there will be no decision making based solely on automated means.

The BISTRO trial was designed to use routine data collection where possible, and for this purpose data linkage is required with UK Renal Registry and Hospital Episodes Statistics (HES), via NHS Digital, databases for the collection of dialysis-related information to the renal registry and events. People treated with in-centre dialysis unfortunately experience many complications, admissions to hospital (both planned and unplanned) and frequently require interventions and clinic attendances from departments external to the kidney dialysis unit. While some of these events are collected as Serious Adverse Events via paper case report forms (CRFs) for trial monitoring purposes, many are not. Detailed knowledge of these is required, in particular for the Health Economic analysis, which is fully funded by the National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme.

Examples of these events include episodes related to vascular access failure and associated interventions, cardiovascular events and their associated interventions, the length and cause of hospital admissions and death.
The data linkage ensures more reliable capture of inter-current events and procedures and post-trial follow up which will allow the study team to determine if there is a legacy effect and link early dialysis events to long-term outcomes.

COLLECTION OF TRIAL DATA: Good clinical practice-trained research staff provided the eligible study participants with information about the trial in the form of a participant information sheet. If the patients agreed to participate, they will have consented by signing a consent form. During the trial duration, the research nurse completed paper forms containing:
(a) administrative data (with identifiable information),
(b) clinical data and
(c) intervention delivery related data.

The research nurse also asked the patient to complete a patient quality of life questionnaire. The data collected by the participating sites (NHS Trusts) and is stored securely for the 438 participants randomised into the trial. These documents were returned to Keele Clinical Trials Unit.

The trial administrator and trial manager Keele Clinical Trials Unit received the paper documents from the recruiting sites and entered them into two types of databases: (a) a management database and (b) a data entry database. Hard copy paperwork is held securely within an access-controlled environment within Keele University. Electronic and hard copy data is pseudonymised as soon processing is complete. Pseudonymised clinical data is linked by a BISTRO Study ID.

DATA REQUESTED: The datasets requested are as follows:
• Hospital Episode Statistics (HES) Admitted Patient Care (APC - required for the evaluation of secondary outcomes: significant events and cost-effectiveness of the intervention
• Hospital Episode Statistics Critical Care (CC) - required for the evaluation of secondary outcomes: significant events and cost-effectiveness of the intervention, particularly in light of COVID-19
• Hospital Episode Statistics Outpatients (OP) - required for the evaluation of secondary outcomes: significant events and cost-effectiveness of the intervention
• Civil Registration (Deaths) Secondary Care Cut – required for long-term legacy effects.

Keele University will send a cohort of 381 individuals identified only by the BISTRO Study ID and the identifiers NHS Number, forename, surname, and date of birth, to NHS Digital for linkage to HES data. All study participants have provided informed consent to allow linkage and collection of this data.

Data is required from when the trial completes follow up in 2021. The study is intended to run for 4 years, and will require outcomes data for the period from April / May 2017 to August 2021.

Study Participants were recruited from centres UK-wide and data is therefore requested across all the devolved nations. This agreement refers to data collected in English Hospitals only.

To collect these data using research nurses would have added considerably to the cost of the trial. The use of routine data makes this trial affordable and therefore possible. All study participants have been provided with information about the nature of the trial and how their personal and sensitive data will be processed, and have given their explicit consent. NHS Digital has considered the adequacy of the consent materials in relation to the application and has determined on balance that data flow is compatible with the consent.

DATA MINIMISATION: only data items necessary for the analysis of the trial have been requested; specifically: Primary Health Economic analysis and pre-specified secondary analyses. All the relevant trial data has been collected using Case Report Forms, except for routinely clinical data collected by external data registries.

For trial participants who have consented to data linkage, routine clinical data collected by units for the Renal Registry returns will be transferred to the CTU for incorporation into the trial database (from 2017 to end of follow-up plus a final download 5 year years post first randomisation for legacy data only) in the form of an electronic downloads (following appropriate testing procedures to ensure data integrity). This includes data collected for individual dialysis sessions (e.g. pre and post weights, blood pressure dialysis prescription), haematology and biochemistry results, and treatment modality timelines, using the Renal Registry Dataset v4.2 (UKRR website). Admission and discharge dates, diagnostic and procedural codes will be obtained from HES datasets via NHS Digital (or its equivalent body for devolved nations).

The data has been requested in line with inclusion and exclusion criteria as described in the study protocol, focussing on adults aged >18 years, within 3 months commencing centre-based maintenance haemodialysis as an outpatient (Day 0) due to advanced kidney disease CKD stage 5 who have given consent to participate on the trial. There were no reported pregnancies in the trial, as expected, as this is mostly an older population.

The sole data controller for this agreement is Keele University. The data will be processed at Keele Clinical Trials Unit which is part of the Keele University and by the University of Warwick for Heath Economics analyses. The Chief Investigator and all co-investigators accessing NHS Digital data are substantive employees of the Keele University or Warwick University.

The UK Renal Registry will be providing data to the Keele University on kidney disease outcomes and a separate data sharing agreement is in place for this.

The funder is NIHR HTA. NIHR do not determine the purpose or the manner in which the data will be processed and are thus not considered a data controller for this agreement.

LEGAL BASIS FOR PROCESSING DATA:
- GDPR (personal identifiable data): Article 6(1)(e) - 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. As a higher education establishment, the University conduct research to improve health care and services.
- GDPR (special category data): This data is processed on the additional condition of: Article 9(2)(j) – Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes.

Outputs:

The trial steering committee has approved the dissemination strategy, with approval by the Sponsor (Keele University). This was developed in close collaboration with the trial management group, Advisory and Dissemination Board facilitated by Kidney Research UK (on behalf of the UK Kidney Research Consortium), BISTRO Patient Advisory Group (PAG) and the trial steering committee.

Trial progress and results aim to be disseminated by other communication channels at Keele University, such as Keele Clinical Trials Unit website, Keele University social media account, and Keele staff and public news (weekly publications) as and when relevant. As BISTRO is funded by NIHR HTA, the trial follows the NIHR research outputs and publications guidance: https://www.nihr.ac.uk/documents/nihr-research-outputs-and-publications-guidance/12250#Notifying_NIHR_of_upcoming_research_outputs

Trial progress and results are hoped to be disseminated to patient organisations, e.g. Devices for Dignity, with the support of the BISTRO PAG.

An BISTRO social medial twitter account (@Keele_BISTRO) and a trial specific website (https://www.keele.ac.uk/bistro/) have also been set up to keep interested patients, carers, clinicians, managers and policy makers up-to-date with trial progress.

Peer-reviewed publications - Data will only be published in aggregated format with small number suppression applied as per the HES analysis guide.

The BISTRO trial has a dissemination plan - the following outputs are planned (estimated 2022/2023):
• Economic evaluation of the intervention and analysis of the benefits of residual kidney function
• In-depth analysis of effect of the intervention on the patient activation and engagement with fluid management
• The impact of dialysis unit practice patterns on primary and secondary endpoints
• Publication of the clinically validated fluid assessment tool and associated educational material, with the potential to develop this into an application suitable for hand-held devices.

Routes of dissemination will be as follows:
• National Meetings (to include study updates and findings):
• Renal Association and British Renal Society (e.g. annual Kidney Week, usually multidisciplinary meeting covering all aspects of nephrology and dialysis treatment).
• International Meetings (via submitted abstracts):
• American Society of Nephrology, European Dialysis and Transplantation Association/European Renal Association, European Dialysis and Transplantation Nurses Association, International Society of Nephrology.

Abstracts for poster and/ or oral presentation aim to be submitted to national and international conferences, such as UK Kidney Week, The European Renal Association – European Dialysis and Transplant Association (ERA-EDTA), American Society of Nephrology and World Congress of Nephrology (estimated 2022/2023).

The funder (NIHR) requires sight of all output before it is made public (with the exception of individual tweets).

Processing:

METHODOLOGY
1. Keele University will send in a Cohort of 381 consented patients Study IDs plus NHS Number, Forename, Surname, and Date of Birth to NHS Digital via a Secure Electronic File Transfer (SEFT) service.

2. NHS Digital will link the cohort and extract the HES and Mortality data, and then remove the identifiers. NHS digital will then send the pseudonymised extracts back to Keele University via SEFT.

3. Keele University will link the pseudonymised data from NHS Digital* to pseudonymised data from the UK Renal Registry and pseudonymised BISTRO trial data (e.g. Case Report Forms and Questionnaires) via the Study ID to form the final pseudonymised record-level BISTRO trial data set.
*Similar data linkage requests are being processed by the equivalent organisations in the devolved nations.

4. Keele University will then share the final record-level pseudonymised BISTRO trial data set with the University of Warwick for joint data processing and analysis.

Reporting and export procedures for data downloads to common statistical software analysis packages (SPSS, SAS, Stata, R) are provided within Keele University’s secure network.

For the purpose of identifying the correct cohort and obtaining agreed pseudonymised data linkage for the trial the appropriate variables will be shared with UK Renal Registry (renal data, UKRR) and NHS Digital- equivalent bodies in devolved nations (for equivalent HES and mortality data). No special category data, specifically no health data, will be sent from Keele University. UKRR and NHS Digital-equivalent bodies in devolved nations will return a pseudonymised dataset (BISTRO BISTRO Study ID and variables containing no identifying data) to Keele University for data linkage.

DOWNLOADING DATA FROM SEFT AND UPLOAD TO KEELE CTU SERVER
A member of the BISTRO study team will request Keele University IT to create a temporary folder with restricted access on the secure Keele University server (logging this action in the audit history). The data recipient will then use a Keele University secure remote device using 2-factor authentication via VPN to log into NHS Digital’s Secure Electronic File Transfer (SEFT) system and save downloaded file(s) into the temporary folder.

After the data download, the data recipient – who is still accessing the server via a secure remote device will upload the NHS Digital data from the temporary folder into the Clinical Trials Unit (CTU) secure server space as soon as possible with a 2-factor authentication via Virtual Private Network (VPN) enabled for each team member.

A member of the BISTRO study team will request Keele University IT to destroy the initial download folder with the appropriate software and ensure this is logged on the audit history.

NHS Digital data linkage and analysis will be performed on the Keele University CTU server. Keele University is able to limit access within the CTU server according to department and permissions. In this instance, the BISTRO study area in Password access is randomised and changes every 60 days.

BISTRO Trial identifiable data is stored separately to the pseudonymised datasets, and no linkage will be attempted.

Notes:
- The use of Microsoft Office 360 is for a transient, short-term data transfer method only. Data is not stored on SharePoint for longer than the period of transfer and no data analysis/manipulation will be conducted on this Cloud Platform.
- All Keele and Warwick substantive staff complete mandatory Information Governance and GDPR training on an annual basis. Please note that Warwick will only have access to NHS Digital data after the data linkage has taken place at Keele University.
- Physical access to the both University’s offices are restricted to personnel authorised to access these premises. The computers used are encrypted or work within an encrypted environment.

The Keele University will store the identifying details of participants linked with a pseudonym BISTRO Study ID and will separately store the “clinical” data (i.e. data provided by participants, recruiting sites and obtained from other providers such as NHS Digital, UKRR, etc.) as “pseudonymised” data containing the pseudonym BISTRO Study ID but no other identifying details.

The two datasets (initial PID containing dataset submitted to NHS Digital and returned pseudonymised dataset) would be kept separate and not re-linked. Access to the database with identifiable information will be restricted according to the Keele University’s Data Security and Protection Toolkit. Datasets from NHS Digital (and UKRR) would be added into the trial database using the pseudonym BISTRO Study ID for linkage with other data. For patients in England, this includes data from: the trial case report forms, participant questionnaires and UKRR.

Appropriate pseudonymised variables from HES and Civil Registration data will be shared with the University of Warwick. It will be used to derive event rates (e.g. hospital admission rates and death rates) for Health Economics analysis, together with BISTRO Study ID (pseudonymised dataset) will be shared with University of Warwick (data processor). A separate data sharing agreement has been established with the data processing organisation.

Microsoft Limited provide Office 360 SharePoint Cloud Services for the University of Warwick and Keele University and are therefore listed as a data processor. They supply support to the system, but do not access data. Therefore, any access to the data held under this agreement would be considered a breach of the agreement. This includes granting of access to the database[s] containing the data.

TRANSFER OF DATA FROM / TO WARWICK UNIVERSITY FROM KEELE UNIVERSITY
As a part of the data analysis, a pseudonymised subset of the trial data (using the BISTRO Study ID), with pre-defined appropriate variables, will be then shared with University of Warwick via SharePoint (Microsoft Office 365) which both Universities have.

The files are in the form of excel documents with password protection applied.

A member of the BISTRO study team will request Keele University IT to create a temporary folder with restricted access on the secure Keele University server (logging this action in the audit history).

A member of the BISTRO study team will move the files from the Keele CTU Server, to the temporary folder, and then upload the file to a specifically created secure folder on Microsoft Office 360 SharePoint. SharePoint access to the folder requires a 2-factor authentication for the folder to be opened, i.e. authorised person’s email address and a random code generated every time access is required. The folder will be accessible to only authorised University of Warwick substantive staff that will be performing the analyses. In order to access the folder, the users will be sent a link to the folder and will need to request a code to enter the folder. This code will need to requested every time access is required. The code will be different for each request.

A member of the BISTRO study team will request Keele University IT to destroy the initial download folder with the appropriate software and ensure this is logged on the audit history.

A member of the BISTRO study team at the University of Warwick accesses the secure folder on Microsoft Office 360 SharePoint and downloads the files directly into the Warwick University’s CTU secure server. Study team members at University of Keele and University of Warwick must ensure the data files within the Microsoft 360 SharePoint folder is then deleted and removed from the recycle bin.

The data will be processed and analysed in the Warwick CTU secure server.

When all the analyses have been performed, the pseudonymised data will be shared back to Keele University via SharePoint (as described in steps 6 – 1 above in reverse)

Trial data will be processed at specific trial time points: upon receipt for data linkage, data analysis including the use of the datasets by external processors (e.g. University of Warwick).

HES and Civil Registration data will be processed to derive the secondary outcomes for the trial, as set out above. These will then be added to the main analysis file for the trial. Both statistical and health economic analysis plans have been developed and were signed off by the trial steering committee. This will be followed to address secondary objectives of the trial to determine the effect of the intervention on:
- Significant events, including vascular access failure and associated interventions, cardiovascular events, hospital admissions and death, including the use of routinely collected data and long-term legacy effects beyond trial completion using data linkage to routine health care databases such as the UK Renal Registry (via the Renal Registry), Hospital Episode Statistics and Mortality data via NHS Digital (and their equivalent bodies in Wales, Scotland and Northern Ireland).
- Objective measures of dialysis efficacy and safety: e.g. inter-dialytic fluid gains, intra-dialytic hypotension, urea-reduction ratios (routine data)
- Cost effectiveness of the intervention – a cost-utility analysis will be undertaken to determine the primary outcome of incremental cost (or cost savings) per quality-adjusted life year (QALY) gained.

DATA RETENTION
Retention of data at participating sites (site archiving) will be for 5 years from the end of the trail - this is only applicable for BISTRO Trial collected data by the site, for their participants, not the NHS Digital data referred to in this agreement. At the end of the 5 year period, each site will be contacted to destroy this data. The reason for this is to resolve any potential queries after data lock.

Retention of the final dataset for the BISTRO trial will be for 10 years post end of the study as per Keele Standard Operating procedure (SOP 17 - CTU Archiving and Destruction) at the Keele University approved location. This will include the data linkage data, e.g. pseudonymised NHS Digital data.

HES DISCLOSURE CONTROL / SMALL NUMBER SUPPRESSION
In order to protect patient confidentiality, when presenting results calculated from HES record level data, outputs will contain only aggregate level data with small numbers suppressed in line with HES Analysis Guide. When publishing HES data, you must make sure that:
· cell values from 1 to 7 are suppressed at a local level to prevent possible identification of individuals from small counts within the table.
· Zeros (0) do not need to be suppressed.
· All other counts will be rounded to the nearest 5.
Data will not be made available to any third parties other than those specified except in the form of aggregated outputs with small numbers suppressed in line with the HES Analysis Guide.