1994, 308: 111-112. This is the second of my three kinds of stepped wedge trial. Jadad A: Randomised Controlled Trials. The methodological descriptions of stepped wedge studies, including methods of randomisation, sample size calculations and methods of analysis, are not always complete. Stepped wedge trials, with their one-way cross-over, are suited to interventions which might be easy enough to introduce to a cluster, but are much harder (practically or politically) to take away again. You want everyone to have the intervention? Regarding the results in the first example data set, methods 1 and 3 showed a strong positive intervention effect, which disappeared after adjusting for time. National Library of Medicine In this presentation, Dr. Karla Hemming outlines the potential conditions under which an SW-CRT might be an appropriate choice. Without randomisation, for instance, if doctors were to decide who should be treated with the experimental drug, any apparent differences in outcomes could be attributed to other disparities among the patients, rather than whether or not they were treated with the experimental drug. Nevertheless, policy decisions such as this are rarely informed by randomised trials, as the logistics and feasibility of conducting such studies is often perceived to be insurmountable. Grant AD, Charalambous S, Fielding KL, Day JH, Corbett EL, Chaisson RE, De Cock KM, Hayes RJ, Churchyard GJ: Effect of routine Isoniazid preventative therapy on Tuberculosis incidence among HIV-infected men in South Africa. At the individual level however, individual participation and exposure can vary greatly between trials. Google Scholar. Library, Archive & Open Research Services, Key Resources To Learn About Stepped-wedgeTrials, Logistic, ethical, and political dimensions of stepped wedge trials: critical review and case studies, Designing a stepped wedge trial: three main designs, carry-over effects and randomisation approaches, Sample size calculation for a stepped wedge trial, Design and analysis of stepped wedge cluster randomized trials, Analysis and reporting of stepped wedge randomised controlled trials: synthesis and critical appraisal of published studies, 2010 to 2014, Five questions to consider before conducting a stepped wedge trial, Anti-slavery and human trafficking statement. Precisely how this care is organised and delivered is also significant. The second is logistic in that assurance of fairness will also increase the likelihood of cluster participation. Journal of Vascular Surgery. (121). PMC A stepped wedge describes the shape that is produced from a schematic illustration of the design (see figure 1). Comprehensive literature review of studies or protocols using a stepped wedge design. Commencing at week 1, where all . Having clusters cross over allows you to study the effect of the intervention by studying changes within a cluster, as well as by comparing clusters that are in different conditions at any given moment (see Is a stepped wedge trial really a randomised controlled trial?). Of course, if you have 100 clusters in your trial you could potentially have as many as 100 different sequences, with each cluster randomly allocated to one of these, or you could have a smaller number of sequences with several clusters randomised to each. PubMedGoogle Scholar. In such circumstances, determining the order in which participants receive the intervention at random is likely to be both morally and politically acceptable and may also be beneficial for trial recruitment [7]. However, given the small number of clusters in CRTs, randomisation can no longer be relied on to ensure this balance. Google Scholar. We use MailChimp as our marketing automation platform. Five questions to consider before conducting a stepped wedge trial British Medical Journal. Before Controlled Clinical Trials. There are two key (non-exclusive) situations in which a stepped wedge design is considered advantageous when compared to a traditional parallel design. International Journal of Epidemiology, 49(3), 10431052. Stepped wedge CRTs (SW-CRTs) are a variant of CRTs in which all clusters begin in the control phase and end in the intervention phase, and different clusters switch from control to intervention at different time points in random order. Research OUTREACH. 2016 Dec;13(6):641-650. doi: 10.1177/1740774516656583. This is particularly problematic for studies randomizing a small number of heterogeneous clusters. 6705 Rockledge Drive, Room 733, MSC 7990 Cook and Campbell were possibly the first authors to consider the potential for experimentally staged introduction in a situation when an innovation cannot be delivered concurrently to all units [3]. BMC Med Res Methodol. Indeed, we do not apply any methodological filters. Required fields are marked *, Research Outreach We exclude multiple baseline designs, which are generally applied to analyse the response of single subjects to an intervention and where analysis is undertaken separately for each individual, since exposure to the intervention is often delayed until a stable baseline has been achieved rather than being determined randomly [11]. Levy RW, Rayner CR, Fairley CK, Kong DCM, Mijch A, Costello K, McArthur C: Multidisciplinary HIV adherence intervention: A randomized study. The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). SWTs can be thought of as a modified crossover design as the clusters are in both treatment arms at different times. Delaying and withholding interventions: ethics and the stepped wedge trial BMC Med Res Methodol 6, 54 (2006). Different methods to analyze data from a stepped wedge trial design reveal different aspects of a possible intervention effect. [http://www.ness.bbk.ac.uk], Belsky J, Melhuish E, Barnes J, Leyland AH, Romaniuk H, the National Evaluation of Sure Start Research Team: Effects of Sure Start local programmes on children and families: early findings from a quasi-experimental, cross-sectional study. Results: The Department for Education and Skills ruled out a cluster trial where the deprived areas identified as in need of Sure Start would be randomised to either receive the intervention or act as controls, since to intervene in some areas but not in others was judged unacceptable. The design also imposes some practical implementation challenges, such as preventing contamination between intervention participants and those waiting for the intervention and ensuring that those assessing outcomes are blind to the participant's status as intervention or control to help guard against information bias. Moreover, the SW-CRT may be at greater risks of other biases than the conventional parallel-CRT. ).Therefore, a baseline table presented by study arm includes changes over time in the outcome which undermine the purpose of a baseline table, which is reported so that the randomisation can be assessed by the reader. In particular, stepped wedge trials are examples of trials which randomise their participants in " clusters ". In order for SWT designs to be fully reported and to enable readers to judge their strengths and weaknesses, it is important to describe how individuals participate, including the start and duration of exposure and whether they are exposed to control, intervention, or both, and how outcome measurements are obtained. The latter uses matched pairs of wards to control for inter-temporal changes, randomising one ward in each pair to early intervention and one to late intervention. This is important given the difficulties associated with blinding participants and those delivering the intervention from their status as intervention or control, since it will nearly always be evident to both groups when the step from control to intervention occurs. Study designs may need to allow time to realise the effect of the intervention. This can increase the duration of the SW-CRT when compared with a parallel-CRT. 14 Stepped wedge cluster randomised trials are run over an extended interval of time, allowing clusters to cross over from a routine care or 'control' condition to an experimental intervention condition during. Westend CAS Limited resources or capacity can mean that the roll-out is staggered. 1-3 In a parallel cluster randomized trial (parallel-CRT) half the clusters (such as hospitals, wards or . If the stakeholders, such as nurses, GPs or hospital management, can be persuaded to randomise the roll-out, a SW-CRT can be carried out and provide a means to conduct an evaluation which otherwise would not be possible. 10.1093/ije/28.1.10. An example of the logistics of a stepped wedge trial design is shown in Figure 1, which shows a stepped wedge design with five steps. The design involves random and sequential crossover of clusters from control to intervention until all clusters are exposed. [22] also consider the impact of time on effectiveness. Yet, Prof Karla Hemming (University of Birmingham) and Prof Monica Taljaard (Ottowa Hospital Research Institute) examine a new type of study design that brings hope and the chance to improve the evidence base on which these policy decisions are made. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. The SW-CRT involves randomisation of clusters to different sequences that dictate the order (or timing) at which each cluster will switch to the intervention condition. Other considerations Keywords: 2015 Aug 17;16(1):1. Strengths and weaknesses of a stepped wedge cluster randomized - PubMed The remaining eight studies are cluster trials, with houses, clinics, wards and districts receiving the intervention in each time period. Its simply an observational study a study of what actually happens and thats all the description it needs. (You might be hard-pressed to prevent these hospital colleagues from sharing notes on their respective approaches.) Analysis of cluster randomised stepped wedge trials with repeated cross-sectional samples. The potential benefits of employing a stepped wedge design can be illustrated by considering the 20 m evaluation of the Sure Start programme in the UK [8]. By the end of the study, all participants will have received the intervention, although the order in which participants receive the intervention is determined at random. The hunt for efficient, incomplete designs for stepped wedge trials In stepped wedge cluster randomized trials (SWTs), clusters are randomly allocated to crossover to the intervention at different time-points and all clusters receive the intervention eventually [1, 2].Stepped wedge trials are used in both explanatory and pragmatic research [3, 4].In explanatory research, the intervention is primarily implemented to study its effect. The mean number of steps in the remaining five cluster studies was 13 (range 429). Somerville M, Basham M, Foy C, Ballinger G, Gay T, Shute P, Barton AG: From local concern to randomised trial: the Watcombe Housing Project. doi: 10.1093/jacamr/dlac070. An official website of the United States government. We contacted the authors of the conference proceeding report identified by a citation check and a protocol identified by the Controlled Trials Register but were unable to obtain sufficient information about these trials to include them in our review. Two of the cluster studies [12, 18] did not indicate whether stepping was randomised. Considering the scientific advantages of the stepped wedge design, it has rarely been used in practice and hence we advocate the design for evaluating a wide range of interventions, although we are not the first to do so [2628]. The three most commonly used and well defined are: Designs based on a closed cohort of participants; designs based on an open cohort; and the continuous-recruitment, short exposure designs. It is only permissible to include terminal end-points (such as death) in studies with a repeated cross-sectional design: in individual/cohort designs if a participant has died in the control phase, it is impossible for them to die in the intervention stage. Stepped wedges were (and still are) tools used for calibrating X-ray equipment. Some researchers have moved to presenting baseline characteristics by study condition instead, e.g. This makes blinding of those assessing outcomes particularly important in protecting against information biases, particularly where outcomes are subjective. Basic information about each of the included studies is shown in Tables 1, 2, 3. Practical difficulties with providing the intervention to everyone simultaneously were mentioned in four studies, due to insufficient resources in three [4, 14, 21] and logistical difficulties in two [4, 18]. From the scientific point of view, randomisation would eliminate allocation bias and the stepped wedge deign would have offered a further opportunity to measure possible effects of time of intervention on the effectiveness of the intervention. The duration of exposure to the control or the intervention, and therefore duration of follow up, will also vary between individuals and must be considered. The primary method(s) of data analysis for each study are shown in Table 4. The studies included in the review described their study design as either stepped wedge or phased introduction/implementation. Thank you for expressing interest in joining our mailing list and community. The clusters might be geographical regions (see The first stepped wedge trial) or hospitals, for example. 2021 Dec;24(6):1948-1961. doi: 10.1111/hex.13334. The stepped wedge cluster randomised trial is a novel research study design that is increasingly being used in the evaluation of service delivery type interventions. Background: Stepped wedge cluster randomized trials (SW-CRT) are increasingly used to evaluate new clinical programs, yet there is limited guidance on practical aspects of applying this design. Table 2 identifies that a number of different interventions were being evaluated, with vaccination, screening and education plans emerging as the most common interventions. sharing sensitive information, make sure youre on a federal 2003, 14: 805-809. The known advantages hold, whereas most of the disadvantages were not applicable to this application. Part of The overall time-scale of the trial is divided into a number of periods. A recent paper by Hussey and Hughes [25] also provides detail regarding the analysis of stepped wedge designs. big cities), only a fraction of individuals is sampled from the cluster to provide outcome measurement. Designing a stepped wedge trial: three main designs, carry-over effects government site. 2006 Nov 8;6:54. doi: 10.1186/1471-2288-6-54. A stepped wedge describes the shape that is produced from a schematic illustration of the design (see figure 1). Then, at predefined intervals, researchers randomly assign groups to receive the intervention. Another feature posing challenges in reporting results is the assessment of whether or not the randomisation has resulted in study conditions that are balanced at baseline in terms of important covariates. The stepped wedge design is a sub-type of a randomized controlled trial, where individuals or groups are studied at different times. International Journal of STDs & AIDS. And taking more time has another advantage: you can experimentally change the conditions at a cluster as time goes by. Different methods to analyze stepped wedge trial designs revealed PubMed Central In a SW-CRT, the clusters move sequentially from control to intervention conditions in a randomised order. The main advantage was that we were able to include a large number of patients. An alternative approach is stepped-wedge randomization ( Hussey and Hughes 2007 ). UW Biostatistics Working Paper Series. If you have an interest in health services research its likely that youve already come across studies describing themselves as stepped wedge trials. 2023 BioMed Central Ltd unless otherwise stated. 10.1001/jama.293.22.2719. The stepped-wedge study, by randomising the order of any planned policy roll-out across participating units, is appealing but is likely to face several important risks of bias. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. Theres no doubting the impact that this approach is having on research to improve healthcare. There is a wide range of SWT designs. This paper offers a good summary of the questions researchers should answer and the issues they should consider before starting a SWT. The evaluation has instead used a non-randomised control group, consisting of 50 "Sure Start-to-be" communities, compared to the 260 Sure Start intervention communities. (Statisticians will tell you that a much better design, on paper at least, is to allow clusters to cross in both directions.). However not all of the studies included here would fulfil the methodological requirements for a controlled trial and hence we propose that if a stepped wedge design is to be applied, authors should register their trial on the Controlled Clinical Trials Register and follow appropriate reporting guidelines, such as the CONSORT statement or its equivalent for cluster trials [23, 24]. Trials. If there are three or more possible sequences then you have a stepped wedge triaI. You dont need a stepped wedge trial for that. 1999, 30: 203-208. Randomisation means that any differences in patient outcomes, such as how long they survive after a cancer diagnosis, can be attributed to the experimental drug and all other possible explanations can be ruled out. 2019 Oct 12;19(1):298. doi: 10.1186/s12888-019-2291-4. This reporting guideline highlights the additional complexities of the design and requires that investigators provide a clear justification for using this design. Others will experience either the control or the intervention, such as in a SWT involving individuals with acute conditions. 10.1136/bmj.328.7441.702. Method 1 compares all the intervention measurements with the control measurements. What future extensions of the SW-CRT approach might further enhance its applicability? Google Scholar, National evaluation of Surestart. The motivation for randomising in clusters might be that the new intervention is delivered at the cluster level. 2022 Jun 29;4(3):dlac070. It would be much less practical in this case to randomise individual patients, and to have some health professionals at a hospital who had received the new training and who only treated intervention patients, and others who had not had the training who only treated control patients. Determining the order in which communities received the intervention at random would have been demonstrably impartial and hence a fair way to allocate resources. All of the studies bar one [15] identified one or more motivations for employing a stepped wedge design, although the level of detail regarding motivations varied. To a clinical trial statistician like myself, "efficiency" usually means finding a way to get the evidence you need with the fewest participants (or fewest . While a parallel-CRT can also be conducted in a staggered way, it becomes infeasible if the roll-out of the intervention is constrained to only a couple of clusters at a time. Similar to reporting of the design of a SWT, there is no standard to guide reporting and analysis of results. The site is secure. The stepped wedge design may also be appropriate for cost-effectiveness analyses of interventions that have already been shown to be effective. Prof Karla Hemming and Prof Monica Taljaard examine a new type of study design, the stepped-wedge cluster randomised trial, that offers the chance to improve the evidence base on which policy decisions are made. In a paper by Hargreaves et al., the authors conclude that an ethically sound, well-designed, and well-conducted SWT with appropriate analysis can provide strong evidence of the effects of an intervention. The Stepped-Wedge Clinical Trial: Evaluation by Rolling Deployment Of the cluster studies, three [14, 17, 18] are cohort designs (with the same individuals in each cluster in the pre and post intervention steps) and the remainder are repeated cross-section designs (with different individuals in each cluster in the pre and post intervention steps). Five questions to consider before conducting a stepped wedge trial. Finally, it allows for pragmatic research, whereby a phased and randomised roll-out provides an opportunity for a more rigorous evaluation. By selecting any of the topic options below you are consenting to receive email communications from us about these topics. The stepped wedge trial design: a systematic review. Dr. Hemming has recently led the CONSORT extension for the stepped wedge cluster randomized trial. Stepped wedge trials are cluster-randomised trials where clusters cross over from the control to the active intervention condition during the trial, according to a randomised schedule [].Typically, every cluster will begin the trial in the control condition and end in the intervention condition, but the stepped wedge design in the broadest sense allows for more variation than this, including . If you are happy for us to contact you in this way, please tick below. Journal of the American Medical Association.
Black Population In Ontario Canada, Articles W