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Randomised controlled trials are the best research design for decisions about the effect of different interventions but randomisation does not, of itself, promote the applicability of a trial's results to situations other than the precise one in which the trial was done. While methodologists and trialists have rightly paid great attention to internal validity, much less has been given to applicability. This narrative review is aimed at those planning to conduct trials, and those aiming to use the information in them. It is intended to help the former group make their trials more widely useful and to help the latter group make more informed decisions about the wider use of existing trials. We review the differences between the design of most randomised trials (which have an explanatory attitude) and the design of trials more able to inform decision making (which have a pragmatic attitude) and discuss approaches used to assert applicability of trial results. If we want evidence from trials to be used in clinical practice and policy, trialists should make every effort to make their trial widely applicable, which means that more trials should be pragmatic in attitude.

PROMOTING PARTNERSHIP FOR HEALTH This book forms part of a series entitled Promoting Partnership for Health publishedin association with the UK Centre for the Advancement of Interprofessional Education (CAIPE).The series explores partnership for health from policy, practice and educational perspectives.

AbstractObjectiveTo explore qualitatively the relationship between selected trial design choices and proxies for scientific and clinical uptake in a cohort of published randomized controlled trials (RCTs) of corticosteroids for COVID-19, to identify design characteristics that may result in trials with potential to eliminate equipoise, achieve uptake and help reduce research waste. Study Design & SettingA systematic literature search and qualitative, narrative review of published RCTs (up to April 13, 2021) evaluating the effectiveness of systemic corticosteroids in treatment of COVID-19. We extracted information on sample size, number of centres, single or multi-country conduct, dates of initiation and of publication, risk of bias and pragmatism scores, and also on impact measured by citation in scientific literature and in clinical guidelines. We qualitatively compared design features of the highest impact versus other trials. ResultsRECOVERY was by the most impactful of the seven eligible RCTs as it was 10 times more frequently cited in peer-reviewed literature and influenced all the selected COVID-19 treatment guidelines. All trials started recruiting from similar dates. RECOVERY was a single country, multi-centre platform trial at low risk of bias, features which also fail to distinguish it from the other trials. RECOVERY was distinguished by more strongly pragmatic design features, more centres, and more rapid recruitment resulting in a larger sample size, and early publication. ConclusionHigher pragmatism scores may contribute to recruiting more centres and more rapid recruitment of patients at each centre, leading to larger size, earlier publication, and greater scientific and guideline uptake. By eliminating equipoise RECOVERY rendered other simultaneous trials redundant. Further work is needed to confirm these findings in a larger quantitative study and to identify the individual contribution of each characteristic of pragmatism to conduct and impact of trials, and their interaction in different national contexts. Until then research waste might be reduced by designing trials with as many of the characteristics of RECOVERY as is feasible.

Background First articulated by Schwartz and Lellouch (1967), randomized controlled trials (RCTs) can be conceptualized along a continuum from more explanatory to more pragmatic. The purpose and intent of the former is to test interventions under ideal contexts, and the purpose and intent of the latter is to test interventions in real-world contexts. The PR agmatic E xplanatory C ontinuum I ndicator S ummary-2 (PRECIS-2) is a validated tool that helps researchers make decisions about the elements of the trial to match the overall purpose and intent of the trial along the continuum. The PRECIS-2 tool has guided the design of hundreds of RCTs. However, a few aspects of the tool would benefit from greater clarity, including its application to provider-focused implementation trials rather than patient-focused intervention trials. Main text We describe the newly developed PRECIS-2-Provider Strategies (PRECIS-2-PS) tool, an extension of the PRECIS-2 tool, which has been adapted for trials testing provider-focused strategies. We elaborate on nine domains that can make a provider-focused trial more explanatory or more pragmatic, including eligibility, recruitment, setting, implementation resources, flexibility of provider strategies, flexibility of intervention, data collection, primary outcome, and primary analysis. We detail the complementary roles that researchers and stakeholders play in the trial design phase, with implications for generalizability of trial results to the contexts in which they are intended to be applied. Conclusions The PRECIS-2-PS tool is designed to help research and practice teams plan for provider-focused trials that reflect the overall intent and purpose of the trial. The tool has potential to help advance the science of provider-focused strategies across a range of trials, with the ultimate goal of facilitating the adoption, integration, and sustainability of provider-focused strategies outside the context of trials.

Background Pragmatic trials aim to generate evidence to directly inform patient, caregiver and health-system manager policies and decisions. Heterogeneity in patient characteristics contributes to heterogeneity in their response to the intervention. However, there are many other sources of heterogeneity in outcomes. Based on the expertise and judgements of the authors, we identify different sources of clinical and methodological heterogeneity, which translate into heterogeneity in patient responses—some we consider as desirable and some as undesirable. For each of them, we discuss and, using real-world trial examples, illustrate how heterogeneity should be managed over the whole course of the trial. Main text Heterogeneity in centres and patients should be welcomed rather than limited. Interventions can be flexible or tailored and control interventions are expected to reflect usual care, avoiding use of a placebo. Co-interventions should be allowed; adherence should not be enforced. All these elements introduce heterogeneity in interventions (experimental or control), which has to be welcomed because it mimics reality. Outcomes should be objective and possibly routinely collected; standardised assessment, blinding and adjudication should be avoided as much as possible because this is not how assessment would be done outside a trial setting. The statistical analysis strategy must be guided by the objective to inform decision-making, thus favouring the intention-to-treat principle. Pragmatic trials should consider including process analyses to inform an understanding of the trial results. Needed data to conduct these analyses should be collected unobtrusively. Finally, ethical principles must be respected, even though this may seem to conflict with goals of pragmatism; consent procedures could be incorporated in the flow of care.

To propose a tool to assist trialists in making design decisions that are consistent with their trial's stated purpose. Randomized trials have been broadly categorized as either having a pragmatic or explanatory attitude. Pragmatic trials seek to answer the question, “Does this intervention work under usual conditions?,” whereas explanatory trials are focused on the question, “Can this intervention work under ideal conditions?” Design decisions make a trial more (or less) pragmatic or explanatory, but no tool currently exists to help researchers make the best decisions possible in accordance with their trial's primary goal. During the course of two international meetings, participants with experience in clinical care, research commissioning, health care financing, trial methodology, and reporting defined and refined aspects of trial design that distinguish pragmatic attitudes from explanatory. We have developed a tool (called PRECIS) with 10 key domains and which identifies criteria to help researchers determine how pragmatic or explanatory their trial is. The assessment is summarized graphically. We believe that PRECIS is a useful first step toward a tool that can help trialists to ensure that their design decisions are consistent with the stated purpose of the trial.

Reviews have repeatedly noted important methodological issues in the conduct and reporting of cluster randomized controlled trials (C-RCTs). These reviews usually focus on whether the intracluster correlation was explicitly considered in the design and analysis of the C-RCT. However, another important aspect requiring special attention in C-RCTs is the risk for imbalance of covariates at baseline. Imbalance of important covariates at baseline decreases statistical power and precision of the results. Imbalance also reduces face validity and credibility of the trial results. The risk of imbalance is elevated in C-RCTs compared to trials randomizing individuals because of the difficulties in recruiting clusters and the nested nature of correlated patient-level data. A variety of restricted randomization methods have been proposed as way to minimize risk of imbalance. However, there is little guidance regarding how to best restrict randomization for any given C-RCT. The advantages and limitations of different allocation techniques, including stratification, matching, minimization, and covariate-constrained randomization are reviewed as they pertain to C-RCTs to provide investigators with guidance for choosing the best allocation technique for their trial.

Robust evidence of the effectiveness of task shifting of antiretroviral therapy (ART) from doctors to other health workers is scarce. We aimed to assess the effects on mortality, viral suppression, and other health outcomes and quality indicators of the Streamlining Tasks and Roles to Expand Treatment and Care for HIV (STRETCH) programme, which provides educational outreach training of nurses to initiate and represcribe ART, and to decentralise care. We undertook a pragmatic, parallel, cluster-randomised trial in South Africa between Jan 28, 2008, and June 30, 2010. We randomly assigned 31 primary-care ART clinics to implement the STRETCH programme (intervention group) or to continue with standard care (control group). The ratio of randomisation depended on how many clinics were in each of nine strata. Two cohorts were enrolled: eligible patients in cohort 1 were adults (aged ≥16 years) with CD4 counts of 350 cells per μL or less who were not receiving ART; those in cohort 2 were adults who had already received ART for at least 6 months and were being treated at enrolment. The primary outcome in cohort 1 was time to death (superiority analysis). The primary outcome in cohort 2 was the proportion with undetectable viral loads (<400 copies per mL) 12 months after enrolment (equivalence analysis, prespecified difference <6%). Patients and clinicians could not be masked to group assignment. The interim analysis was blind, but data analysts were not masked after the database was locked for final analysis. Analyses were done by intention to treat. This trial is registered, number ISRCTN46836853. 5390 patients in cohort 1 and 3029 in cohort 2 were in the intervention group, and 3862 in cohort 1 and 3202 in cohort 2 were in the control group. Median follow-up was 16·3 months (IQR 12·2–18·0) in cohort 1 and 18·0 months (18·0–18·0) in cohort 2. In cohort 1, 997 (20%) of 4943 patients analysed in the intervention group and 747 (19%) of 3862 in the control group with known vital status at the end of the trial had died. Time to death did not differ (hazard ratio [HR] 0·94, 95% CI 0·76–1·15). In a preplanned subgroup analysis of patients with baseline CD4 counts of 201–350 cells per μL, mortality was slightly lower in the intervention group than in the control group (0·73, 0·54–1.00; p=0·052), but it did not differ between groups in patients with baseline CD4 of 200 cells per μL or less (0·94, 0·76–1·15; p=0·577). In cohort 2, viral load suppression 12 months after enrolment was equivalent in intervention (2156 [71%] of 3029 patients) and control groups (2230 [70%] of 3202; risk difference 1·1%, 95% CI −2·4 to 4·6). Expansion of primary-care nurses' roles to include ART initiation and represcription can be done safely, and improve health outcomes and quality of care, but might not reduce time to ART or mortality. UK Medical Research Council, Development Cooperation Ireland, and Canadian International Development Agency.

There is a growing appreciation that our current approach to clinical research leaves important gaps in evidence from the perspective of patients, clinicians, and payers wishing to make evidence-based clinical and health policy decisions. This has been a major driver in the rapid increase in interest in comparative effectiveness research (CER), which aims to compare the benefits, risks, and sometimes costs of alternative health-care interventions in ‘the real world’. While a broad range of experimental and nonexperimental methods will be used in conducting CER studies, many important questions are likely to require experimental approaches – that is, randomized controlled trials (RCTs). Concerns about the generalizability, feasibility, and cost of RCTs have been frequently articulated in CER method discussions. Pragmatic RCTs (or ‘pRCTs’) are intended to maintain the internal validity of RCTs while being designed and implemented in ways that would better address the demand for evidence about real-world risks and benefits for informing clinical and health policy decisions. While the level of interest and activity in conducting pRCTs is increasing, many challenges remain for their routine use. This article discusses those challenges and offers some potential ways forward.