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Scientific Abstract

At-Risk Registers Integrated into primary care to Stop Asthma crises in the UK  (ARRISA-UK)

A pragmatic cluster randomised trial with nested economic and process evaluations examining the effects of integrating at-risk asthma registers into primary care with internet-based training and support.


Pragmatic cluster randomised controlled trial of a complex intervention with nested mixed methods process and economic evaluations.


UK general practices

Target population

Patients at high risk of asthma exacerbations/death


262 primary care practices, excluding practices with existing formal, prospective processes for targeting patients with at - risk asthma. All the patients identified as having at - risk asthma according to a validated algorithm (n=9170) will be included, except those with recorded refusal for use of anonymous data in research.

Health technology 

At - risk registers will be created using automated electronic searches identifying at -risk criteria. Training will be delivered via web - based eLearning modules and “webinars” to representatives of all categories of practice staff to train them on how to respond to electronic alerts/flags to ensure best practice care. The flags will tag the electronic health records of at - risk patients to alert all staff at all patient - practice interactions. A practice based study lead will receive email reminders at 6 weeks and 6 months.


Control practices will continue routine care, including Quality and Outcome Framework driven practice- based annual asthma reviews and patients’ use of routine and emergency primary and secondary care services as required the but not the flagging or training.


The primary outcome is the difference in the proportion of at - risk patients with an asthma- related crisis event (A&E attendance, hospitalisation or death) over 12 months. Secondary outcomes: time to first crisis event, asthma control, prescribed medications, medication adherence, smoking status, all cause admission and death, health care costs in all and “at - risk” asthma patients.

Anonymous routinely- collected clinical data from patients will be captured. Health economic analysis will be from an NHS perspective, where the primary outcome will be the measure of effectiveness.

Routine data on processes of care, and questionnaires from practice staff completed before, during and after the training and after 12 months of the intervention, plus exit focus groups and interviews will contribute to the process evaluation.

Sample size

In order to have 90% power to detect a difference in primary outcome from 7% to 5% assuming an average cluster size of 35 (ICC 0.01) we require a minimum of 235 clusters and 8204 patients. To allow- for 10% drop - out we will recruit 262 clusters, 9170 patients.

Project timetable

Regulatory approvals ( - 6 to 0 months), production and evaluation of training programme in one region (0 to 6 months), recruitment of practices (2 to 12 months), training (9 to 24 months), follow up (21 to 36 months), focus groups (30 to 36 months), completion/cleaning dataset (37- 42mth), analysis & report (42 - 48mth).

Study funding 

Study funding is from the NHS’s National Institute of Health Research, Health Technology Assessment Programme, sponsored by the University of East Anglia (UEA) and based at the Norwich CTU at Norwich Medical School. Prof. Andrew Wilson, Clinical Professor/Consultant Physician of respiratory medicine at the UEA and Norfolk and Norwich University Hospitals NHS Foundation Trust is the Chief Investigator. He is working with a distinguished team of researchers from other universities, general practice, the charity Asthma UK, and other research organisations throughout the UK.

Expertise in team

Expertise in patient and public involvement (PPI), primary and secondary care physicians with research and clinical interest in at - risk asthma, health technology assessments, pragmatic cluster randomised controlled trials, statistics, health economics, qualitative research and comprehensive evaluation of complex intervention.


This website presents independent research commissioned by the National Institute for Health Research (NIHR). The views and opinions expressed by authors in this website are those of the authors and do not necessarily reflect those of the NHS, the NIHR, NETSCC, the Health Technology Assessment Programme or the Department of Health.