Evaluating Diuretics in Normal Care (EVIDENCE)
Research type
Research Study
Full title
Evaluating Diuretics in Normal Care (EVIDENCE) Evaluating Diuretics in Normal Care (EVIDENCE) - a cluster randomised evaluation of hypertension prescribing policy
IRAS ID
219202
Contact name
Alex Doney
Contact email
Sponsor organisation
University of Dundee
Duration of Study in the UK
2 years, 0 months, 1 days
Research summary
For the majority of common chronic clinical conditions managed in the contemporary NHS there are a range of similar drugs that available. For many of these drugs there is a lack of comparative effectiveness data to aid prescribers in choosing between them. Thus, there is often an assumption of equivalent clinical effectiveness that has not been formally demonstrated. The following study protocol outlines one such situation in the context of management of raised blood pressure and a novel study design that will allow the generation of comparative effectiveness data to inform prescribing this area. It is hoped that this study may be used as a model to facilitate further investigation of the comparative effectiveness of many commonly used drugs across a range of common chronic conditions.
Thiazide and Thiazide-like diuretic drugs are fundamental component of management of raised blood pressure, they are very commonly prescribed and there are several similar diuretics to available to choose from. Guidelines advising which diuretic to prescribe for hypertension in the UK have suggested that bendroflumethiazide should no longer be the diuretic of first choice and that chlortalidone or indapamide should become the preferred treatment. The evidence underpinning this recommendation is not strong. Indeed, many local prescribing policies have not adopted this recommendation on the basis that it is not sufficiently evidence-based. It should be noted that even a relatively minor difference in effectiveness between these prescribing strategies would translate into a large number of events due to the widespread use of these agents. For example, a 1 mmHg difference in population blood pressure (BP) resulting from the various prescribing policies would translate into a 4.2% difference in incident myocardial infarction (MI) and a 6.8% difference in stroke (CVA).
The purpose of the present proposal is to evaluate whether the recommended policy is equivalent to the older policy with regard to a composite cardiovascular endpoint of MI, CVA, hospitalised Congestive Heart Failure (CHF) or vascular death. Because chlortalidone has become very expensive (£88 per month) and therefore rarely used in the UK, only indapamide-recommending and bendroflumethiazide-recommending policies will be compared. This will be achieved by randomly allocating prescribing policy in primary care practices. Half of participating practices will implement a policy of using indapamide as their first-line thiazide/thiazide-like diuretic in the treatment of hypertension. The other half will apply a policy of prescribing bendroflumethiazide as their first-line thiazide/thiazide-like diuretic. The study incorporates the concept of a learning healthcare environment whereby health is improved by sharing data across organisations to drive better patient care. The evaluation will be run by a steering committee in collaboration with the British Hypertension Society research network.REC name
East of Scotland Research Ethics Service REC 1
REC reference
17/ES/0016
Date of REC Opinion
4 Apr 2017
REC opinion
Further Information Favourable Opinion