Cluster randomized trials of prescription medicines or prescribing policy: public and general practitioner opinions in Scotland

Evaluating Diuretics in Normal Care (EVIDENCE): a feasibility report of a pilot cluster randomised trial of prescribing policy in primary care to compare the effectiveness of thiazide-type diuretics in hypertension

Background

Obtaining evidence on comparative effectiveness and safety of widely prescribed drugs in a timely and cost-effective way is a major challenge for healthcare systems. Here, we describe the feasibility of the Evaluating Diuretics in Normal Care (EVIDENCE) study that compares a thiazide and thiazide-like diuretics for hypertension as an exemplar of a more general framework for efficient generation of such evidence. In 2011, the UK NICE hypertension guideline included a recommendation that thiazide-like diuretics (such as indapamide) be used in preference to thiazide diuretics (such as bendroflumethiazide) for hypertension. There is sparse evidence backing this recommendation, and bendroflumethiazide remains widely used in the UK.

Methods

Patients prescribed indapamide or bendroflumethiazide regularly for hypertension were identified in participating general practices. Allocation of a prescribing policy favouring one of these drugs was then randomly applied to the practice and, where required to comply with the policy, repeat prescriptions switched by pharmacy staff. Patients were informed of the potential switch by letter and given the opportunity to opt out. Practice adherence to the randomised policy was assessed by measuring the amount of policy drug prescribed as a proportion of total combined indapamide and bendroflumethiazide. Routinely collected hospitalisation and death data in the NHS will be used to compare cardiovascular event rates between the two policies.

Results

This pilot recruited 30 primary care practices in five Scottish National Health Service (NHS) Boards. Fifteen practices were randomised to indapamide (2682 patients) and 15 to bendroflumethiazide (3437 patients), a study population of 6119 patients. Prior to randomisation, bendroflumethiazide was prescribed to 78% of patients prescribed either of these drugs. Only 1.6% of patients opted out of the proposed medication switch.

Conclusion

The pilot and subsequent recruitment confirms the methodology is scalable within NHS Scotland for a fully powered larger study; currently, 102 GP practices (> 12,700 patients) are participating in this study. It has the potential to efficiently produce externally valid comparative effectiveness data with minimal disruption to practice staff or patients. Streamlining this pragmatic trial approach has demonstrated the feasibility of a random prescribing policy design framework that can be adapted to other therapeutic areas.

Trial registration

ISRCTN Registry, ISRCTN46635087. Registered on 11 August 2017

When I use a word . . . . No jab, no job? A benefit:harm balance analysis

The current debate about whether individuals should be entitled to work in the healthcare sector if they decline to be vaccinated against SARS-CoV2 has been largely informed by personal opinions and argument by analogy. A benefit:harm balance analysis suggests that while vaccination has a highly favourable benefit:harm balance, the balance in instituting a "no jab, no job" policy is highly uncertain and may be unfavourable. Furthermore, there are practical difficulties and legal uncertainties. The much misunderstood precautionary principle dictates that if the benefit:harm balance of an intervention is unclear and may be unfavourable, the intervention should not be undertaken. Furthermore, the onus is on those who believe that the benefit:harm balance will be favourable to prove that it is so; it is not for the sceptics to prove that it isn't. In the absence of good evidence in favour, this is an intervention that would be best avoided.

Evaluating Diuretics in Normal Care (EVIDENCE): protocol of a cluster randomised controlled equivalence trial of prescribing policy to compare the effectiveness of thiazide-type diuretics in hypertension

INTRODUCTION

Healthcare systems must use treatments that are effective and safe. Regulators licensed many currently used older medications before introducing the stringent evidential requirements imposed on modern treatments. Also, there has been little encouragement to carry out within-class, head-to-head comparisons of licensed medicines. For commonly prescribed drugs, even small differences in effectiveness or safety could have significant public health implications. However, conventional clinical trials that randomise individual subjects are costly and unwieldy. Such trials are also often criticised as having low external validity. We describe an approach to rapidly generate externally valid evidence of comparative safety and effectiveness using the example of two widely used diuretics for the management of hypertension.

METHODS AND ANALYSIS

The EVIDENCE (Evaluating Diuretics in Normal Care) study has a prospective, cluster-randomised, open-label, blinded end-point design. By randomising prescribing policy in primary care practices, the study compares the safety and effectiveness of commonly used diuretics in treating hypertension. Participating practices are randomised 1:1 to a policy of prescribing either indapamide or bendroflumethiazide when clinically indicated. Suitable patients who are not already taking the policy diuretic are switched accordingly. All patients taking the study medications are written to explaining the rationale for changing the prescribing policy and notifying them they can opt-out of any switch. The prescribing policies' effectiveness and safety will be compared using rates of major adverse cardiovascular events (hospitalisation with myocardial infarction, heart failure or stroke or cardiovascular death), routinely collected in national healthcare administrative datasets. The study will seek to recruit 250 practices to provide a study population of approximately 50,000 individuals with a mean follow-up time of two years. A primary intention-to-treat time-to-event analysis will be used to estimate the relative effect of the two policies.

ETHICS AND DISSEMINATION

EVIDENCE has been approved by the East of Scotland Research Ethics Service (17/ES/0016, current approved protocol version 5, 26 August 2021). The results will be disseminated widely in peer reviewed journals, guideline committees, National Health Service (NHS) organisations and patient groups.

TRIAL REGISTRATION

ISRCTN 46635087 . Registered on 11 August 2017 (pre-recruitment).

Cluster randomised trials of prescribing policy: an ethical approach to generating drug safety evidence? A discussion of the ethical application of a new research method

For most chronic medical conditions, multiple medications are available and prescribers often have limited evidence about which therapy is likely to be the most effective and safe for an individual patient. As many patients are exposed every day to medicines that may be less effective than available alternatives, this is of public health importance. Cluster randomised trials of prescribing policy offer an opportunity to rapidly obtain evidence of comparative effectiveness and safety. These trials can pose a low risk to patients and cause minimal disruption to usual care. Despite the potential scientific value of this approach, there remain valid concerns about consent, medication switching and the use of routinely collected data in research. We discuss these concerns with reference to an ongoing pilot study (Evaluating Diuretics in Normal Care (EVIDENCE) - a cluster randomised evaluation of hypertension prescribing policy, ISRCTN 46635087, registered 11 August 2017).

Evaluation of Noninvasive Prenatal Testing (NIPT) guidelines using the AGREE II instrument

Objective: The rapid increase of cell-free fetal DNA analysis for Down syndrome screening requires evidence-based clinical practice guidelines for noninvasive prenatal testing (NIPT). Several studies show that the quality of many guidelines is low and there are still many health areas where this quality is not systematically evaluated. Given the absence of research, in the NIPT field, we used an internationally validated tool to evaluate a set of three NIPT practice guidelines and to look at dimensions that can be improved.Methods: Four appraisers, experts in prenatal screening, evaluated three main NIPT guidelines published in the last 2 years using the AGREE II (Appraisal of Guidelines for Research and Evaluation II), a tool specifically designed for guideline quality appraisal.Results: Guidelines scored higher in domains related with scope, purpose, and clarity of presentation, and lower in stakeholder involvement and rigor of development. Intradomain items evaluation showed asymmetries between guidelines. The UK-NSC was the guideline with the best scores.Discussion: Several areas of NIPT guidelines, such as stakeholders involvement, selection of supporting evidence, external reviews, updating processes, and competing interests disclosure, can be improved. Appraisers recommend modifications to all NIPT guidelines that can lead to substantial improvements in their methodological quality and subsequently make a contribution to prenatal screening improvement.