Request for HES Data to analyse outcomes in the NIHR-funded ATTOM study

The Access to Transplant and Transplant outcome measures (ATTOM) study is a UK-wide cohort study of patients with kidney disease receiving dialysis or with a kidney transplant. Its aim is to investigate patient-specific factors which influence progress and outcomes. Baseline data were collected from 2011-2013 and include the results from patient surveys and case notes review for 6842 patients (which included 1139 patients from Wales, Northern Ireland and Scotland, who are not included in the proposed data linkage, i.e.: cohort size 6842-1139=5703).

Study data contain details of patients’ comorbidities, markers of socioeconomic status such as education, employment, marital status and accommodation, demographics and health literacy (as defined by the Single-item literacy screener: a validated measure of individual health literacy, which is the question ‘How often do you need to have someone help you when you read instructions, pamphlets or other written material from your doctor or pharmacy’, answered on a 5-point scale, with responses 1-Never, 2-Rarely, 3-Sometimes, 4-Often and 5-Always. Responses ‘Sometimes’, ‘Often’ and ‘Always’; See Taylor et al Kidney International Issue 90; vol 3; Pages 685-695).

Patients with advanced kidney disease such as those included in ATTOM have high rates of comorbidity, especially in the form of cardiovascular disease. Because of these comorbidities as well as complications of dialysis or transplantation, they have a high rate of contact with hospital services (emergency care, admissions, outpatients). Data from HES contain details recorded as a result of hospital care, which can be used to examine healthcare use, expenditure and comorbidity, and its relationship to patient-specific factors such as socioeconomic status and health literacy. ATTOM data will be linked to HES (mortality data will be linked at a later date subject to the legal basis being gained) data to allow:

a) Analysis of variations in healthcare utilisation and cost (admission rate, hospital bed days, HRG tariff remuneration, clinic attendance, Emergency Department attendance) in relation to health literacy, socioeconomic status and comorbidity.

b) Comparison of comorbidity data from HES (derived from diagnoses and procedural entries before and during the ATTOM study period, hence start point in 2006) to comorbidity data from the ATTOM dataset (collected by a research nurse from patients’ medical notes), to establish if HES-derived comorbidity data is equal in quality and scope to researcher-collected data from the ATTOM dataset.

c) Survival analysis (from HES initially and linked to ONS mortality data at a later date) in relation to health literacy, socioeconomic status and comorbidity.

Although the linkage of HES data was not specified in the original ATTOM study protocol, the above analyses fit within the first overarching aim of the ATTOM study: to improve equity of access to kidney and pancreas transplantation across the UK. These analyses are primarily concerned with equity of access to treatment and equity of outcome by socioeconomic status and associated factors (including health literacy). By analysing hospital admissions data in this patient group, NHS Blood and Transplant (NHSBT) aim to develop insight into the ways in which socioeconomic factors and health literacy influence patient pathways and may limit access to transplantation. Part b) of the above relates to a specific question about analysis of socioeconomic status in prospective studies (specifically in CKD). Low socioeconomic status is associated with higher comorbidity but also independently with adverse health outcomes. It may be that these factors interact: patients with the same reported baseline comorbidity data but with differing socioeconomic status may develop further comorbidities more quickly (or baseline comorbidities may be more severe in those with low socioeconomic status). In analyses of outcomes, it is difficult to differentiate the effects of comorbidity from the effects of socioeconomic status. This analysis will allow us to compare the consequences of similar comorbidities between patients in different socioeconomic groups. It will be of relevance to the interpretation of our results and to the wider research community.

The data will only be used for this purpose.

1) NHSBT will create a copy of the ATTOM dataset and assign a unique person ID not present in the master ATTOM dataset.

2) NHSBT will send NHS Digital the NHS Numbers, dates of birth and unique IDs.

3) NHSBT will destroy the NHS Numbers, dates of birth and any other identifiers except the unique ID in the copy ATTOM dataset.

4) NHS Digital will provide pseudonymised HES data with the unique ID enabling linkage with the copy ATTOM dataset but not with the master dataset. NHSBT will not attempt to re-link or re-identify individuals to the data received from NHS Digital.

5) All record-level data from the returned dataset will be stored only on the NHS Blood and Transplant(NHSBT) server in a directory with permissions specific to the research team within NHSBT. No data will be accessed by anyone outside of NHS BT.

6) Data will be transferred to statistical packages within the NHSBT server to allow data analysis.

7) Aggregated data with small numbers suppressed in line with the HES analysis guide will be used in draft reports and publications. This data will be made available to the editing team within the ATTOM group. These members are from several institutions listed in the ATTOM protocol.

8) HES ID will be provided to the applicant through this agreement to allow for any future linkage to mortality data (subject to future approval).

Any data used in these draft reports and publications referred to above will be used aggregated with small numbers suppressed in line with the HES Analysis Guidelines.

Data analysis will test the following hypotheses:

a) Healthcare utilisation (admission rate, hospital bed days, HRG tariff remuneration) and patient outcomes (survival from the start of RRT, from transplantation, hospital associated mortality) vary by patient health literacy (defined by responses to the Single Item Literacy Screener), individual-level markers of socioeconomic status and comorbidity in patients from the ATTOM cohort.

b) Comorbidity data derived from diagnoses and procedural information recorded by admissions (prior to the time point of interest) by HES is equal in quality and scope to data collected in the ATTOM study by researchers - this may inform the use of HES data in future observational cohort studies.

No data will be used for commercial purposes, provided in any form to any third party (except when published as aggregate data) or used for marketing of any kind.

All outputs and publications contain only aggregated data with small numbers suppressed in line with the HES Analysis Guide.

All organisations party to this agreement must comply with the Data Sharing Framework Contract requirements, including those regarding the use (and purposes of that use) by “Personnel” (as defined within the Data Sharing Framework Contract ie: employees, agents and contractors of the Data Recipient who may have access to that data).

There will be not data linkage undertaken with NHS Digital data provided under this agreement that is not already noted in the agreement.

Data will only be accessed and processed by substantive employees of NHS Blood and Transplant (NHSBT) and will not be accessed or processed by any other third parties not mentioned in this agreement.

When processing of the linked ATTOM-HES data has been completed, the ATTOM study will have analysed variations in hospital resource use and outcomes associated with health literacy, socioeconomic status and comorbidity. Without linked data from NHS Digital these analyses would not be possible.The target date for completion of the work is 2022 As specified in the ATTOM study protocol, all published output will be open-access (available without charge to the public). All outputs and publications contain only aggregated data with small numbers suppressed in line with the HES Analysis Guide.

Dissemination of results will be as follows:

1) The results of these analyses will form part of planned academic publications in nephrology and public health journals, and presentations at national/international academic meetings (nephrology, public health). This will allow dissemination of the results of these analyses to clinicians and policymakers in nephrology communities worldwide, with subsequent influence on policy.

2) Because the analysis concerns UK patients, the results will be of direct relevance to UK NHS policy. Analyses using ATTOM data have shown that people with low health literacy have reduced access to kidney transplantation, and that this effect is likely to promote socioeconomic inequity in transplant access. Interventions to support people with low health literacy therefore have potential to reduce this inequity and improve outcomes, but have not yet been developed. NHSBT aim to apply for research funding to develop and test such a complex intervention. The proposed HES analysis will provide further evidence in support of this application.

In other healthcare settings (eg: USA nephrology, UK and USA non-nephrology medicine), low health literacy has been associated with increased non-routine healthcare use, but reduced use of preventative healthcare. The suggested analysis of HES data is expected to identify differences in patterns of healthcare use among those with low health literacy- most likely higher expenditure and more use of emergency care. These findings would support interventions to ameliorate the effects of low health literacy in the UK Chronic Kidney Disease population. This analysis will contribute to the development and of a complex intervention as described above.

3) The NIHR-funded ATTOM study has established routes for dissemination of results which include:

a) Presentation at the annual NHS Blood and Transplant Renal Transplant Services Meeting (which invites transplant lead clinicians UK-wide)

b) Stakeholder meetings (which invite clinical leads from UK renal units)

Patient/public representation is required by the NIHR at ATTOM meetings.

All outputs will contain only data that is aggregated with small numbers suppressed in line with the HES Analysis Guide

Research using ATTOM/HES data (and future ONS mortality data pending legal basis obtained) examining variations in healthcare use and expenditure in the context of health literacy, socioeconomic status and comorbidity will expand current knowledge.

For example, results from ATTOM have shown that socioeconomic inequity in access to kidney transplantation appears to be driven in part by health literacy differences. Analysis of healthcare service use data allows more detailed examination of mechanisms underlying this association and would inform policy changes to reduce inequity (possibly by targeting low health literacy groups). Demonstration of higher healthcare costs (from PbR data) among those with low health literacy would add weight to the promotion of initiatives to improve access to care for this group (with resulting reductions in inequity).

Benefits to health and social care will be measurable at the point of dissemination of results, target date August 2020.

Achievement of these objectives will be of relevance to the population of NHS patients receiving dialysis treatment or living with a kidney transplant (the number of patients in these groups in 2013 was 56,940 (UK Renal Registry 17th Annual Report 2014)).

Benefit to these patients will come from research-driven change in policy to improve equity of access to treatment (as described above). Direct communication of results to patient groups will happen as part of ATTOM's Public and Patient Involvement commitment.

Processing of the HES data has started - the data have been cleaned, and cost data is being generated using the HRG grouper. This will allow the analyses above to proceed. None of the above benefits have yet been achieved, in line with the timeline of the original application. The extension is required to allow continuation of this work.