We performed a cluster multicentre randomized controlled clinical trial to evaluate the effect of applying clinical pathways to process and outcome indicators and to the costs sustained to assist the patients with heart failure. This article describes the detailed statistical analysis plan for the help trial, including an amendment and rationale for amendment made to originally planned sensitivity analyses. Cluster randomised controlled trial evaluating the. Provides a historical overview of the development and application of crts in research, along with key references. To conduct a nonrandomised clustercontrolled trial to assess the impact of an unconditional ctp on acute malnutrition and its associated risk factors in children aged 659 months, living in idp camps in the afgooye corridor, a region close to mogadishu, somalia.
The general practice is the unit of allocation and study participant because the intervention aims to improve prescribing at a practice level. Cluster randomized trial an overview sciencedirect topics. The study took place from march 2009 to march 2010 in zanzibar, united republic of tanzania. Fortyfive per cent lower acute injury incidence but no. The study is a cluster randomised controlled trial with schools as unit of. The intervention comprised a stepwise protocol for the treatment of pain for eight weeks, with additional followup lasting four weeks from the end of treatment. Ethical issues in the design and conduct of cluster. A complete guide to understanding cluster randomised trials written by two researchers with extensive experience in the field, this book presents a complete guide to the design, analysis and reporting of cluster randomised trials. Whilst many characteristics of cluster randomized trials are in common with patient randomized trials, the adoption of a cluster randomized design has some implications for the design, conduct and analysis of the trial. In this clusterrandomised controlled trial of a theoretically developed, school and familybased obesity prevention programme targeting 6 to 7yearold chinese children, delivered over 12 months, we found a significant favourable intervention effect on reducing bmi z scores, which was also highly cost effective.
Example study diagram for the registernow1 steppedwedge randomised controlled trial. Fortyfive per cent lower acute injury incidence but no effect on overuse injury prevalence in youth floorball players aged 1217 years who used an injury prevention exercise programme. Our objective was to assess the effectiveness of reducing af exposure on child linear growth and serum af levels in rural areas in eastern kenya. Pitfalls of and controversies in cluster randomization trials. The national ethical committee, research council of zanzibar, approved the study protocol. Lets chat community health approaches to dementia in. Design and analysis of cluster randomization trials in. Study designa twoarm cluster randomised controlled trial. We will use a cluster randomised controlled trial figure 1 to investigate whether a decision support tool in electronic primary care records safely increases anticoagulant prescribing in eligible patients with af. After presenting some basic concepts, hayes and moulton focus on the clustering aspect of the design. Be able to adequately report the results of a cluster randomization trial.
Disadvantages compared with individually randomised controlled trials include greater complexity in design and analysis, and a requirement for more participants. A cluster randomised trial crt is a randomised controlled trial in which preexisting groups, called clusters, of individuals are randomly allocated to treatment arms. A steppedwedge trial or swt is a type of randomised controlled trial or rct, a scientific experiment which is structured to reduce bias when testing new medical treatments, social interventions, or other testable hypotheses. How big should the pilot study for my cluster randomised. In recent years, various researchdriven projects developed software platforms for the selection of patient cohorts. The randomised control trial rct is a trial in which subjects are randomly assigned to one of two groups. Background a stepped wedge cluster randomised trial swcrt is a multicentred study which. Cluster randomised trials crts involve randomisation of groups clusters of individuals to control or intervention conditions. Cluster size variability and imbalance in cluster randomized controlled trials. A randomized controlled trial or randomized control trial.
For example, clusters may be clinical practices or schools where the individuals are patients and school children, respectively. Provides an overview of considerations for designing and implementing crts in health care systems. All clusters start under the control condition, and baseline. This trial of help is a definitive, pragmatic, superiority, cluster randomised. Evaluation of cluster randomized controlled trials in subsaharan africa petros isaakidis. A key property of cluster randomization trials is that inferences are frequently intended to apply at the individual level while randomization is at the cluster or group level. A new dependence parameter approach to improve the design of cluster randomized trials with bin.
Climate schools n 6, preventure n 7, combined climate schools and preventure cap. Thus the unit of randomization may be different from the unit of analysis. When considering a cluster randomised design, these advantages needs to be. A randomised controlled trial of general practitioner safety advice for families with children under 5. In a traditional randomised controlled trial rct, it is the individual patient that is allocated to an intervention or control group, and standard statistical analyses on participant outcomes are used to evaluate if the intervention was effective. Much of what lindquist wrote, however, also applies to clinical and public health interventions. Cluster randomized trials increasingly are being used in health services. Rct is a type of scientific often medical experiment that aims to reduce certain sources of bias when testing the effectiveness of new treatments.
Analysis of a clusterrandomised trial in education this is an expanded version of a talk given to the workshop on cluster randomised trials at the first conference on randomised controlled trials in the social sciences, university of york, september 2006. General practice and patient eligibility the study took place in the 202014 in. The control group received the usual treatment and care. Effectiveness of family integrated care in neonatal.
Evaluation of cluster randomized controlled trials in sub. Cluster randomised trials pragmatic clinical trials unit. With respect to study design, randomized controlled trials rcts as well as analysis of quantitatively synthesized rct data are considered the gold standard for evaluating efficacy in clinical research and constitute evidence for medical treatment. Introducing the new consort extension for steppedwedge cluster.
A brief history of the cluster randomised trial design ncbi. Randomized controlled trials rcts are the hallmark of evidencebased medicine and form the basis for translating research data into clinical practice. Mobile phones improve antenatal care attendance in. Detailed statistical analysis plan for a cluster randomised controlled. Analysis of cluster randomized trials in primary care. A cluster randomised trial is a study design which randomises groups of participants to each arm of a study rather than individuals. A brief history of the cluster randomized trial design. Participants completed questionnaires at baseline, 6, 12, 24 and 36 months postbaseline including the brief symptom. Cluster randomization trials crts are experimental studies in which intact social units. The prospective study will use a steppedwedge cluster randomised controlled trial design working with 12 aboriginal community controlled health services acchss across four states of australia. Sample size calculations for crxo trials need to account for both the cluster randomisation and crossover aspects of the design.
Trial design this was a two arm, pragmatic, cluster randomised trial, with general practices as clusters allocated in a 1. The study design and intervention have previously been described in detail. A key consideration during the design of a cluster randomised trial is the similarity or correlation between individuals within a cluster, which could be a village, social group, region or administrative area. Facilitated patient experience feedback can improve nursing care. Thus, most sections of this protocol support tool apply directly to cluster randomized trials. Current issues in the design of cluster randomization trials allan donner, phd, frsc.
Cluster randomised controlled trials are also known as cluster randomised trials, grouprandomised trials, and placerandomized trials. Cluster randomized trials rethinking clinical trials. Its use is likely to grow as we move towards the learning healthcare system2 and large simple trials. For example, a cluster might be within a gp practice, hospital or community. The use of the cluster randomized crossover design in. The fundamental appeal of the study design is the fact that all. A cluster randomized trial crt is a trial in which individuals are randomized in. How big should the pilot study for my cluster randomised trial be.
In a crxo trial, not only are clusters of individuals rather than individuals themselves randomized to trial arms, but also each cluster participates in each arm of the trial at least once in separate periods. How to design and conduct a randomised controlled trial. Effectiveness and costeffectiveness of the daily mile on. We did this multicentre, clusterrandomised controlled trial in 25 nicus in canada n18, australia n6, and new zealand n1. Randomised controlled trials rcts, or randomised impact evaluations, are a type of impact evaluation which uses randomised access to social programmes as a means of limiting bias and generating an internally valid impact estimate. Introduction observational studies have documented an association between aflatoxin af exposure and reduced linear growth in infants and young children. Consider a trial in which k clusters of size m are. This is done when it would be difficult give a new treatment to an individual within a community or social group without it affecting the outcome in the standard care arm of the study. Im helping out a researcher with sample size justification for a cluster randomized trial. Each cluster receives each intervention in a separate period of time, forming cluster periods. The chirpy dragon intervention in preventing obesity in. Examples of clusters include villages, hospitals or schools. No, because a randomised controlled trial of individuals would be easier. Cluster randomised controlled trial of behavioural intervention.
Cluster randomised trials, second edition thoroughly describes the aspects of crt designs and the analysis of data from such trials. The programme, which was delivered over one school year, focused on promoting a healthy diet. A 20 minute introduction to cluster randomised trials. A randomized controlled trial to prevent childhood obesity through early childhood feeding and parenting guidance. I may write a bit about that soon, but in the process of double checking my formulas and calculations, i ran across several articles that discussed the pros and cons of cluster randomized trials.
Clinical epidemiology program, ottawa hospital research institute. Crts are in common use in areas such as education and public health research. Evaluating the differential effectiveness of social. Methods and analysis optimising therapy to prevent avoidable hospital admissions in multimorbid older people is a european multicentre, cluster randomised, controlled trial. Clinical trial design methodology for pain outcome studies. The cluster randomized crossover crxo design is gaining popularity in trial settings where individual randomization or parallel group cluster randomization is not feasible or practical. This intervention program will be developed based on the findings of the baseline. Cluster randomized trials crts differ from individually randomized rcts in that the unit of randomization is something other than the individual participant or patient.
A cluster randomised controlled trial study design was used. A cluster randomized controlled trial of a clinical. Mixed effects approach to the analysis of the stepped wedge cluster. Rationale and design of optimising therapy to prevent. In cluster randomised controlled trials, however, informed consent for trial entry that is, for randomisation cannot be obtained individually because one persons choice will impinge on anothers. A communitybased comprehensive intervention to reduce. Physicians, group practices, health plans, or even geographic regions counties or states can be defined as clusters. In a companion paper,2 we report on other important aspects of the design and analysis of cluster randomised controlled trials in evaluating the effectiveness of injury prevention interventions. The pros and cons of cluster randomized trials pmean. How to design efficient cluster randomised trials the bmj. Wired mothers is a pragmatic clusterrandomised controlled trial with the primary healthcare facility as the unit of randomisation.
Cluster cmrcts are a variation on this design using groups clusters of patients rather than individuals randomised to different treatments similar to cluster rcts. This book by richard hayes and lawrence moulton has become the leading methodological text in this area. We chose this design because implementation of the intervention required changes to the provision of care at the unit level. In a cluster randomised crossover crxo design, a sequence of interventions is assigned to a group, or cluster of individuals. The healthy lifestyles programme help trial is being conducted to determine whether a novel schoolbased intervention is effective and costeffective in preventing obesity in 910 yearold children. How to design, analyse and report cluster randomised.
A new cluster randomised trials website has been developed to support those. In this companion paper we focus on sample size calculations for cluster randomised trials and on the methods for statistical analyses of these studies. The use of the steppedwedge cluster randomised trial swcrt is on the. The design and use of cluster randomised controlled trials. In such cases, careful consideration must be given to ensure appropriate trial design, implementation, analysis and reporting.
The impact of reducing dietary aflatoxin exposure on child. Cluster unit randomized trials the office of behavioral. In a traditional rct, a part of the participants in the experiment are simultaneously. Understanding the cluster randomised crossover design. Elsewhere1 we have described the rationale for carrying out cluster randomised controlled trials crcts in injury prevention and discussed key issues relating to the design and ethical conduct of such studies. Hope 4 was an open, communitybased, clusterrandomised controlled trial involving 71 individuals with new or poorly controlled hypertension from 30 communities defined as townships in colombia and malaysia. Effectiveness and costeffectiveness of the daily mile on childhood weight outcomes and wellbeing. Methods a cluster randomised controlled design was used 28 intervention and 28 control. The website has the latest publications, software, discussions and events related to clustered design. A cluster randomized trial crt is a trial in which individuals are randomized in groupsthe group as a whole is randomized and not the individual.
1522 869 766 1202 1100 1364 563 1082 1469 401 501 1190 772 1348 745 1332 1093 426 150 735 946 712 746 1182 1218 303 1455 545 308 1347 246 898 118