Evaluating Diuretics in Normal Care (EVIDENCE) - a cluster randomised evaluation of hypertension prescribing policy
| ISRCTN | ISRCTN46635087 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN46635087 |
| IRAS number | 219202 |
| Secondary identifying numbers | Protocol number: 2016CV12 |
- Submission date
- 09/08/2017
- Registration date
- 11/08/2017
- Last edited
- 20/01/2025
- Recruitment status
- No longer recruiting
- Overall study status
- Ongoing
- Condition category
- Circulatory System
Plain English Summary
Background and study aims
Having high blood pressure increases the chances that a person will suffer a heart attack or stroke in the future. The aim of treating high blood pressure with medication is to reduce this risk. A number of different types of medication are known to be effective in reducing blood pressure and in reducing the risk of heart attack and stroke. One of these medication types is the diuretics, often referred to as “water-tablets”. There are two diuretics commonly used in the UK for the treatment of high blood pressure but we do not know which is better. We know that they both work but one may be more effective than the other in the long term. The EVIDENCE (Evaluating Diuretics in Normal Care) study aims to find out if one of these medications is better than the other at preventing heart attacks and strokes. In everyday practice, GP's and hospital doctors are guided by agreed policies, based upon the best available evidence, in deciding which medications are likely to be the most effective. This study aims to compare the effectiveness of two different prescribing policies for diuretics in preventing heart attacks and strokes.
Who can participate?
Patients aged 18 and older who are diagnosed with a thiazide, or thiazide-like diuretic to treat hypertension.
What does the study involve?
Participating GPs are randomly assigned to one of these two prescribing policies. The doctors within that practice then use that policy to guide their prescribing decisions. As already happens in the NHS, mechanisms for switching from one medication to another is used to help practices adhere to their prescribing policy. GP's and their patients are free to choose what they think is the most appropriate treatment in each individual case. People who are registered in practices taking part in the study have their blood pressure medication managed by their GP in the usual way. If the practice policy requires a change to a patient’s usual diuretic prescription, participants are sent a letter advising them that this will take effect on their next requested prescription. All such patients will be given the opportunity to decline the switch. Participants are followed up with for the cardiovascular outcomes.
What are the possible benefits and risks of participating?
As the two medications in question are currently thought to be effectively the same in terms of benefits and side effects, there will be no direct risk or benefit to a person whose GP practice is taking part in the study.
Where is the study run from?
Medicines Monitoring Unit, University of Dundee (UK)
When is the study starting and how long is it expected to run for?
October 2017 to December 2025
Who is funding the study?
University of Dundee (UK)
Who is the main contact?
Dr Amy Rogers
arogers@dundee.ac.uk
Contact information
Public
Medicines Monitoring Unit
University of Dundee
Medical School
Dundee
DD1 9SY
United Kingdom
 ORCID ID |
0000-0001-5207-7032 |
|---|---|
| Phone | +44 1382 383390 |
| arogers@dundee.ac.uk |
Study information
| Study design | Two-arm cluster randomized study of prescribing policy |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Cluster randomised trial |
| Study setting(s) | GP practice |
| Study type | Treatment |
| Participant information sheet | No participant information sheet available |
| Scientific title | EValuatIng DiurEtics in Normal CarE (EVIDENCE) - a cluster randomised evaluation of hypertension prescribing policy |
| Study acronym | EVIDENCE |
| Study hypothesis | The aim of this study is to formally evaluate the effectiveness of a policy of prescribing bendroflumethiazide versus a policy of prescribing indapamide as first-line choice of thiazide/thiazide-like diuretic in the treatment of hypertension. |
| Ethics approval(s) | Approved 04/01/2017, East of Scotland Research Ethics Service (EoSRES) (Tayside Medical Science Centre (TASC), Ninewells Hospital and Medical School, Dundee, DD1 9SY, United Kingdom; 01382 383878; tay.eosres@nhs.scot), ref: 219202 17/ES/0016 |
| Condition | Hypertension and cardiovascular risk |
| Intervention | Current interventions as of 27/02/2020: There are two study arms. Practices are randomly assigned on a 1:1 basis (using a computer algorithm) to either of two prescribing policies: 1. A policy of using Bendroflumethiazide (2.5mg, oral, once daily) as first choice when a diuretic is required for the treatment of hypertension 2. A policy of using Indapamide (2.5mg, immediate release, oral, once daily) as first choice when a diuretic is required for the treatment of hypertension Practices agreed to adopt the assigned policy for future prescribing and existing routine prescriptions are been switched accordingly. Doctors remain free to select the most appropriate medication for their patients. All patients eligible for a potential medication switch are informed by letter of the policy change. The letter explains the reason for any medication changes and directs patients to visit the study website or contact the study team (by telephone or email) to find out more about the study or to opt-out of the proposed medication change. _____ Previous interventions: There are two study arms. Practices are randomly assigned on a 1:1 basis (using a computer algorithm) to either of two prescribing policies: 1. A policy of using Bendroflumethiazide (2.5mg, oral, once daily) as first choice when a diuretic is required for the treatment of hypertension 2. A policy of using Indapamide (2.5mg, immediate release, oral, once daily) as first choice when a diuretic is required for the treatment of hypertension Individual treatment decisions regarding drug choice, dosage, method and frequency of administration for patients will be left up to the treating GPs. Where patients are already taking thiazide, or thiazide-like, diuretics at the time a practice joins the study, routine repeat prescriptions will be switched to the policy preferred drug, unless clinically indicated. |
| Intervention type | Other |
| Primary outcome measure | The composite cardiovascular outcome (comprising non-fatal MI, non-fatal stroke, hospitalization for congestive heart failure, and vascular death) is measured using electronic record-linkage to national datasets of routinely collected data and supported by information from medical records. |
| Secondary outcome measures | 1. Each individual component of the composite primary outcome will be included as a secondary outcome 2. All-cause mortality is measured using record-linkage to national datasets of routinely collected data The study is primary outcome driven so the outcomes are counted as they occur rather than at defined time periods. We expect that the follow-up process will take around 3 years to accrue sufficient events to power the study. |
| Overall study start date | 21/03/2017 |
| Overall study end date | 31/12/2025 |
Eligibility
| Participant type(s) | Other |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | Both |
| Target number of participants | 100 GP practices of typical size (including approximately 240 individuals prescribed diuretics for hypertension) |
| Total final enrolment | 98 |
| Participant inclusion criteria | 1. Registered patients with a documented diagnosis of hypertension and prescribed a thiazide, or thiazide-like, diuretic in a participating practice 2. Aged 18 years and older |
| Participant exclusion criteria | Does not meet the inclusion criteria |
| Recruitment start date | 01/10/2017 |
| Recruitment end date | 31/07/2023 |
Locations
Countries of recruitment
- Scotland
- United Kingdom
Study participating centre
Ninewells Hospital and Medical School
Dundee
DD1 9SY
United Kingdom
Sponsor information
University/education
TASC (Tayside Medical Science Centre)
Ninewells Hospital & Medical School
TASC Research & Development Office, Residency
Block, Level 3, George Pirie Way
Dundee
DD1 9SY
Scotland
United Kingdom
| Phone | +44 1382 383140 |
|---|---|
| ahsp@dundee.ac.uk | |
| Website | http://www.ahspartnership.org.uk/ahsp |
"ROR" |
https://ror.org/03h2bxq36 |
Funders
Funder type
Research council
No information available
Results and Publications
| Intention to publish date | 30/06/2026 |
|---|---|
| Individual participant data (IPD) Intention to share | No |
| IPD sharing plan summary | Not expected to be made available |
| Publication and dissemination plan | We will publish the study protocol (where possible) and will undertake to make public the study results. The major form of publication will be articles in scientific journals but presentations and press releases may also be made. Protocol and statistical analysis plan will be made available at a later date. |
| IPD sharing plan | Current IPD sharing statement as of 11/11/2022: The datasets generated during and/or analysed during the current study are not expected to be made available because these are anonymised clinical data sets that must be analysed in a secure SAFE HAVEN accessed only by Public Benefit and Privacy Panel (PBPP)-approved individuals and therefore cannot be made publicly available. Only summary statistics (in a publication) will be presented. Previous IPD: The data sharing plans for the current study are unknown and will be made available at a later date. |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Protocol article | 17/11/2021 | 31/01/2022 | Yes | No | |
| Interim results article | feasibility report | 11/03/2022 | 14/03/2022 | Yes | No |
| HRA research summary | 28/06/2023 | No | No |
Editorial Notes
20/01/2025: The IRAS number was added.
21/11/2023: The intention to publish date was changed from 31/12/2023 to 30/06/2026. Total final enrolment added.
20/11/2023: The overall study end date has been changed from 31/12/2023 to 31/12/2025 and the plain English summary updated accordingly.
11/11/2022: The IPD sharing statement and summary were updated.
10/11/2022: The following changes were made to the trial record:
1. The target number of participants was changed from 250 GP practices to 100 GP practices.
2. The recruitment end date was changed from 01/10/2022 to 31/07/2023.
14/03/2022: Publication reference added.
31/01/2022: The following changes were made to the trial record:
1. Publication reference added.
2. Internal review.
02/10/2020: The following changes were made to the trial record:
1. The recruitment end date was changed from 01/10/2020 to 01/10/2022.
2. The overall end date was changed from 01/03/2021 to 31/12/2023.
3. The intention to publish date was changed from 01/10/2021 to 31/12/2023.
4. The plain English summary was updated to reflect these changes.
5. The trial website was added.
27/02/2020: The interventions were changed.
