OUTREACH study: Urine analysis and antihypertensive treatment
Research type
Research Study
Full title
BiOmarkers in Urine, anTihypeRtensive trEAtment and blood pressure Control in Hypertensive patients - OUTREACH Study
IRAS ID
229352
Contact name
Laurence Loubiere
Contact email
Sponsor organisation
University of Manchester
Clinicaltrials.gov Identifier
Duration of Study in the UK
3 years, 0 months, 0 days
Research summary
High blood pressure (also called hypertension) is a condition that affects more than 1 in 4 adults. It can strain the heart and the blood vessels, and increase the risk of stroke, heart attack, heart failure, kidney damage, and death. Failure to take medication as prescribed (i.e. non-adherence) is believed to be common in hypertension because it rarely has noticeable symptoms. The patients recruited in this study will be asked to provide a urine sample at the hypertension clinic to find out if they take their blood pressure medication as prescribed. A group of non-adherent patients will participate in a simple 5-step (Discuss/Explore/Act/Co-operate/Reinforce) intervention in which the patient and the treating doctor will discuss the test result, the reasons for not taking the medication as prescribed, and useful measures to improve adherence.
Our aim is to test if the 5-step intervention helps non-adherent patients to comply with their treatment and lower their blood pressure. Adherence, health outcomes and care costs will be measured and compared with groups of non-adherent and adherent patients who did not receive the intervention.Summary:
BiOmarkers in Urine, anTihypeRtensive trEAtment and blood pressure Control in Hypertensive patients (OUTREACH), was sponsored by the University of Manchester, and the main funder was the British Heart Foundation. Prof Maciej Tomaszewski was the Chief Investigator and reports no competing interests.High blood pressure (BP) is a common chronic condition that, if not properly controlled, can increase the risk of serious health problems such as strokes and heart attacks. Patients with high BP (hypertensive patients) are prescribed antihypertensive medication to help lower their BP. However, these treatments are only effective when taken regularly as directed. Non-adherence, i.e. not following the prescribed treatment plan, can prevent BP from being properly controlled. Concealed non-adherence to antihypertensive treatment (a common reason why BP is not controlled) can lead to unnecessary diagnostic tests and treatment escalations, increasing costs and straining healthcare systems.
Chemical adherence testing (CAT) of urine is an objective method of detecting non-adherence to antihypertensive medication. Through a biochemical analysis of spot urine samples, the assay detects deviations from prescribed antihypertensive treatment. Combining this test with a tailored discussion focused on the reason(s) for not following the prescribed treatment plan for high BP, could potentially provide a tool for healthcare professionals to address the problem of non-adherence in hypertension. The OUTREACH study was conducted to evaluate the potential of urine CAT to safely improve BP control, adherence to treatment and prevent complications of hypertension (through measurement of urinary albumin-creatinine ratio - a marker of kidney damage).
Patients and members of the public were actively involved throughout the study. Before the study began, the study team tested the initial acceptability of the study to patients and the projected consent rates in 38 patients from University Hospital of Leicester. All patients perceived the study as an important project and 86.8% of them confirmed they would participate in the study if invited. Representatives of the Public and Patient Engagement Committee (at the NIHR Biomedical Research Centre in Leicester) confirmed that the “information for patients” leaflet was entirely informative. Patients also assessed the structured interview tool (A-BIT) and confirmed they would be happy to answer the questions related to their adherence to antihypertensive treatment and have the discussion on the reasons for non-adherence based on this tool. A patient representative also served on the study’s Steering Committee and contributed to an independent monitoring on the study’s conduct.
The study was conducted at 12 sites across England and Scotland, beginning on 18th December 2018 and completing on 30th September 2023.
The study recruited non-pregnant hypertensive patients aged > 18 years prescribed at least 2 antihypertensive medications. 879 participants were assessed for eligibility, and 130 non-adherent patients were recruited into the study alongside 70 registered adherent participants. Of the 130 nonadherent patients recruited, 65 were randomised into each arm of the study (arm A = intervention, arm B = standard of care). At the intervention visit (visit 3) recruited participants from arm A were given information on the results of their urine CAT, combined with a tailored discussion on the main reason(s) for deviating from prescribed antihypertensive treatment. Those in arm B received standard clinical care.
A total of 112 (86·2%) and 97 (74·6%) patients attended the follow-up visit 4 and 5, respectively.
Overall, the urine CAT-guided intervention was not associated with a significant change in clinic systolic BP in non-adherent hypertensive patients attending visit 4 (the primary outcome). There was a nominally significant effect on adherence – non-adherent patients who received the intervention showed a greater improvement in adherence at follow-up visit 4 (approximately 3 months after the intervention). Furthermore, health economic analyses did not detect a significant cost-saving associated with the urine CAT-based intervention. Importantly, the study succeeded in engaging under-represented populations, with a strong representation of non-White ethnicity amongst those recruited.
REC name
North West - Greater Manchester South Research Ethics Committee
REC reference
17/NW/0637
Date of REC Opinion
20 Dec 2017
REC opinion
Further Information Favourable Opinion