NHS Digital Data Release Register - reformatted

University Hospitals of Derby and Burton NHS Foundation Trust

Project 1 — DARS-NIC-11221-X6Y6N

Opt outs honoured: No - data flow is not identifiable (Does not include the flow of confidential data)

Sensitive: Non Sensitive

When: 2016/09 — 2020/02.

Repeats: Ongoing, System Access

Legal basis: Health and Social Care Act 2012, Health and Social Care Act 2012 – s261(1) and s261(2)(b)(ii)

Categories: Anonymised - ICO code compliant


  • HES Data Interrogation System
  • Hospital Episode Statistics Admitted Patient Care
  • Hospital Episode Statistics Accident and Emergency
  • Hospital Episode Statistics Outpatients
  • Hospital Episode Statistics Critical Care


Access is provided to the entire HES dataset (non-identifiable) for the specific purposes as listed below. The purpose of the request is to use information available in HES to study epidemiology of acute kidney injury in England. Specifically, the objectives of the research are 1) To study regional variation in dialysis requiring acute kidney injury (AKI-D) in England. 2) To evaluate factors affecting renal and patient outcome in acute kidney injury after medical conditions or procedures 3) To develop AKI risk score for community acquired AKI 4) To study long term patient and renal outcomes after dialysis requiring AKI To date there is a paucity of data on the incidence of AKI whether community or hospital-acquired. The reported prevalence of AKI from US data ranges from 1% (community-acquired) up to 7.1% (hospital-acquired) of all hospital admissions. The population incidence of AKI from UK data ranges from 172 per million population (pmp) per year from early data8 up to 486-630 pmp/year from more recent series, again depending on definition. The incidence of AKI requiring renal replacement therapy (RRT) ranges from 22 pmp/year to 203 pmp/year. An estimated 5–20% of critically ill patients experience an episode of AKI during the course of their illness and AKI receiving RRT has been reported in 4·9% of all admissions to intensive-care units (ICU)12. Data from the Intensive Care National Audit Research Centre (ICNARC) suggests that AKI accounts for nearly 10 percent of all ICU bed days. There are 4 studies from United States (S), reporting that the incidence and case-fatality of AKI has decreased, but the health care system in US is insurance based and the data used is from billing databases with their own limitations. The data will allow lay people, the medical community and healthcare policy makers to appreciate the true burden and variation of this important disease. This is important because it is the first critical step in developing strategies to reduce the incidence of AKI as well as improve outcomes. As such this study is well aligned with initiatives undertaken by NHS England to better understand the burden of AKI in England with the goal of developing national initiatives to reduce the incidence and improve survival. The research will be performed in Derby Teaching Hospital NHS Trust The data from HSCIC will provide information regarding incidence and case fatality of AKI in England and specifically in relation to high-risk cardio-vascular procedures. The data will also be used to specifically develop AKI risk scores for community acquired AKI. The research will be based in UK and there will be no element of this work performed abroad.

Yielded Benefits:

HDIS access allows the licensed user to carry out service evaluation for the Trust. The benefit is also in understanding yearly change in length of stay, mortality for certain group of diseases as identified by ICD 10 codes. Some example - 1) The access to HDIS has allowed the Trust to understand the impact of heart failure services on length of stay and readmission rates at University Hospitals of Derby and Burton NHS Foundation Trust. 2) The licensed user evaluated the number of AKI admissions in Queens Hospital Burton as recognised by coding and by NHS England's AKI algorithm to understand the specificity of the coding. This has led to important financial saving to the Trust by implementing "improving coding" in Queens Hospital, Burton. 3) The same audit also evaluated impact of not recognising AKI and mortality which was higher in Queens Hospital, Burton and has resulted in measures to improve AKI recognition. 4) The other service evaluation which is planned to understand the impact of influenza testing in emergency department and medical assessment unit in reducing hospital admission.

Expected Benefits:

The use of HDIS mean that users and organisations have a secure access, remotely hosted software application for the analysis of HES data. The system is hosted and audited by the HSCIC meaning that large transfers of data to on-site servers is reduced and the HSCIC has the ability to audit the use and access to the data. The provision of a tool enables that rapid analysis can be performed to the latest version of the data where speedy analysis is required to react to either local public health, commissioning or research requirements. There are huge benefits with this research as mentioned below. The use of HES data for AKI epidemiology has resulted in clearer picture of the disease burden in England. As mentioned previously, the health care system is different in each country and though the mortality for AKI has decreased in US, this is not the case for England. The previously provided data has highlighted that mortality for dialysis requiring AKI (AKI-D) remains unchanged in England over last 15-years and urgent action needs to be taken to tackle this. The data shared previously was presented at the World Congress of Nephrology 2015 in Cape Town, European Renal Association meeting in London 2015 and an oral presentation in the European Renal Association meeting in London 2015. 1) The epidemiology of hospitalised acute kidney injury not requiring dialysis in England from 1998 to 2013: retrospective analysis of hospital episode statistics. Kolhe NV, Muirhead AW, Wilkes SR, Fluck RJ, Taal MW. Int J Clin Pract. 2016 Jan 22. doi: 10.1111/ijcp.12774. [Epub ahead of print] 2. National trends in acute kidney injury requiring dialysis in England between 1998 and 2013. Kolhe NV, Muirhead AW, Wilkes SR, Fluck RJ, Taal MW. Kidney Int. 2015 Nov;88(5):1161-9. doi: 10.1038/ki.2015.234. Epub 2015 Jul 29 The previous data has highlighted that the population incidence of both AKI & AKI-D has increased more than 12 folds in England. This research has led to further projects by UK Renal Registry to collect dialysis data for AKI prospectively. The NHS as a whole will benefit. As the results of the analysis are freely available, policy makers can also make use of this to decide important healthcare policies. 1) Benefits aimed are to achieved by working on research question 1 (above): England will be the first country to report accurately the incidence and case-fatality from AKI at regional level from ICD-10 coded definition of AKI. Recent evidence from England indicates that outcome of dialysis requiring AKI is poor, though there is no evidence if this is due to regional variation. This study will be provide evidence if regional evidence exists and the factors influencing the regional variation. This will be useful for service planning at national level to reduce the regional variation and improve outcomes. Target: 12-18 months 2) Benefits aimed are to achieve by working on research question 2 (above): It is unclear if AKI after bypass surgery is influenced by keeping patients on a bypass pump. This study will provide evidence and help clinicians with the knowledge gained to improve patient and renal outcome after cardiac bypass surgery. Target: 12-18 months 3) Benefits aimed to achieve by working on research question 3 (above): A better understanding of the factors associated with acute kidney injury in the form a risk score will help to prevent not only community acquired AKI, but also hospital acquired AKI by stratifying patients, who haven’t developed AKI, into low risk or high risk category. Validation in other regions will increase the robustness of the risks core. Target: 12-24 months 4) Benefits aimed are to achieve by working on research question 4 (above): Long term outcome of dialysis requiring AKI has been hampered by bias in the form of being either from specific centers or specific locations like intensive care. The national data available gives the power to investigate long-term patient and renal outcomes which can be further stratified by region. The benefit of this research questions is that it will identify best practice and set a benchmark for future improvements and will inform strategies that lead to a reduction in mortality rates. Target: 12-24 months. There is increasing evidence that AKI episodes, transient and permanent, lead to increased risk of end stage renal disease and all-cause mortality. The linked data with HES and UKRR will provide longitudinal data confirming and quantifying this relationship. Intervention studies initiated in selected locations in England can help understand the effectiveness and help prevent progression of AKI. In summary, it is expected that the benefits to include further published work in peer-reviewed medical journals, and further findings which may lead to quality improvement initiatives.


Users of HDIS are able to produce outputs from the system in a number of formats. The system has the ability to be able to produce small row count extracts for local analysis in Excel or other local analysis software. Users are also able to produce tabulations, aggregations, reports, charts, graphs and statistical outputs for viewing on screen or export to a local system. Any outputs that are produced from the systems that are to be published or shared will be small number suppressed outputs in line with the HES analysis guide. Users are not permitted to link data extracted from the system to any other data items which make the data identifiable. The results of the analysis will be presented as abstracts or posters in following meetings - Renal Association, British Renal Society, European Renal Association and American Society of Nephrology. The results will also be submitted to following reputed journals like BMJ, Plos Medicine or Lancet and Renal journals like Journal of American Society of Nephrology, Kidney International, Nephrology Dialysis and Transplantation etc It is expected that the analysis will take place in October 2016. Considering the review delays and differing resubmission process of each journals, it is difficult to predict dates. The outputs are for medical professionals in any speciality, given the importance of AKI. The output will also be useful to policy makers and commissioners Many journal articles can be published as open access. All manuscripts will be available free of charge and will be available to the public. Outputs will contain only aggregate level of data and small numbers suppressed in line with the HES analysis guide. As mentioned above the output may change as a result of findings, but the Trust expect to produce outputs in 12 months’ time. AKI in relation to cardiological procedures (cardio-pulmonary bypass graft), as mentioned earlier, will be analysed followed by risk modelling for community acquired AKI. Additional information to address DAAG comments 5th April 2016; 1) Regional variation in dialysis requiring acute kidney injury (AKI-D) in England – 6 months a. The outputs will be in the form of regional incidence of AKI-D in each region of England from 2001 to 2015. b. Regional mortality of AKI-D in each year from 2000 to 2015. c. Tables or forest plot of multivariable analysis of mortality determinants 2) Evaluate factors affecting renal and patient outcome in acute kidney injury after medical conditions or cardiac procedures – 12-18 months a. Table and forest plots of multivariable analysis of determinants of AKI-D after CABG 3) Risk score for AKI in community – 12-18 months a. Table and forest plots of multivariable analysis of determinants of AKI-D after CABG b. Table of AKI risk score and results of validation from other regions of England. 4) Long term patient and renal outcome after AKI-D – 24 months a. Kaplan-Meir survival analysis curves to demonstrate acturial survival. b. Cox-proportional hazard analysis and survival curve demonstrating adjusted hazards for patient and renal survival.


HDIS is accessed via a two-factor secure authentication method to approved users who are in receipt of an encryption token ID. Users have to attend training before the account is set up and users are only permitted to access the datasets that are agreed within this agreement. Users log onto the HDIS system and are presented with a SAS software application called Enterprise Guide which presents the users with a list of available data sets and available reference data tables so that they can return appropriate descriptions to the coded data. The access and use of the system is fully auditable and all users have to comply with the use of the data as specified in this agreement. The software tool also provides users with the ability to perform full data minimisation and filtering of the HES data as part of processing activities. Users are not permitted to upload data into the system. Licences are for named users only. Logon details are non-transferable and for use only by the named user. The data obtained will be used to calculate Charlson’s comorbidity index and will be analysed in SPSS v22, statistical software. The data will not be accessed from outside UK. Only direct employees of the Trust will have access to the data, with only the named user(s) having access to the HDIS system itself. Record-level data cannot be downloaded from the HDIS system. Linkage to other data sources is only permitted where this does not increase the risk of re-identification such as geographical databases which are in the public domain. As only aggregated data can be downloaded from HDIS, and it is not possible to upload data into HDIS, any linkage is only carried out on aggregated data. For subsequent linkage with UK renal registry (UKRR) for renal outcome of AKI-D, HSCIC will be requested to perform linkage and anonymise the data before processing for analysis. Any request for linkage to the UKRR would be subject to an application to the HSCIC. Only aggregated data will be downloaded from HDIS. However the applicant will receive separately an extract in relation to a patient cohort recognised as having AKI (by ICD 10 code of N17) and requiring dialysis (by X403 & X404), excluding patients with Chronic Kidney Disease (CKD) stage 5. The additional procedure codes which will be investigated will be K40-K44 for cardiac bypass surgery and other code for On-Pump bypass (Y73.1). Under this agreement, record level data will be provided by HSCIC in relation to the above cohort established within HDIS. This record level data will be an extract once agreed with the applicant, and will subsequently be analyzed to study long term outcome – Renal as well as patient outcome (survival) over a period of 15 years. The applicant will calculate the time on survival (days/months) and use statistical analysis (cox proportional hazard analysis and Kaplan Meir survival analysis) to plot and compare survival in different age groups and region. The Trust also anticipates a request to HSCIC in future to perform anonymised linkage to other dataset such as UKRR (UK Renal Registry) dataset to study the progression of AKI into CKD - such linkage is not part of this agreement. No patient identifiable data will be used for analysis and publishing. For detailed statistical analysis, the Trust may need to obtain statistical advice from Trust statistician.