Open-cohort designs for cluster-randomised trials in institutional settings: A methodology bolt-on to DCM-EPIC

机构环境中整群随机试验的开放队列设计：DCM-EPIC 的附加方法

• 批准号: MR/P026761/1
• 负责人: Rebecca Walwyn
• 金额: $ 32.47万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FP026761%2F1
• 关键词: Open; cohort; designs; cluster; randomised

A randomised clinical trial (RCT) is an accepted research method for testing interventions. Recruited participants are often randomly assigned to receive the intervention or to a control group. Calculations are made at the start to work out how many participants are needed to get a precise result. However, many interventions in care homes or hospital wards work at a setting (unit, ward or care home) level. This means the care home or hospital ward, and individual participants in them, are randomised as a cluster. This is called a cluster RCT. In cluster RCTs the number of clusters as well as the number of participants is important.The applicants are currently carrying out a cluster RCT that is looking at how effective an intervention called Dementia Care Mapping (DCM) is at reducing agitation in people with dementia. Staff members use DCM to identify improvements they can make in the care home. Therefore, any resident living in the care home while DCM is being used, will potentially benefit.There are two accepted ways of designing a cluster RCT. A closed-cohort design follows the same individuals over time, collecting data on them at the start, end and sometimes at middle time points during a trial. This allows the effects of the intervention to be analysed on individuals and the group. Our DCM trial uses this design. A problem in care homes, hospitals and other settings is the high turnover of individuals due to discharge/moving or death. Additional individuals also enter the setting over this time and are exposed to the intervention but are not included in the RCT. The longer the RCT is, the more individuals are likely to drop out. To manage this many more clusters and individuals have to be recruited at the start of the RCT to be sure of having enough individuals still there at the end. This makes the research very expensive. In our trial of DCM, around 50% of residents will have left the trial by our final 16-month follow-up, mainly due to death. A cross-sectional design is the current alternative. This design collects data on individuals in a cluster at the start and at end of the RCT. It does not track individuals over time, instead assuming that individuals differ at each data collection point. This again reduces the number of individuals that can be recruited at later time points.A different design that could be used is an open-cohort cluster RCT. In this design, all newly eligible individuals are recruited and data collected on them either continuously or at set data collection time points after randomisation. Potential advantages of this design are it may be more (i) economical because fewer clusters need to be recruited, (ii) flexible as it can allow research questions relating to individuals exposed to the intervention throughout an RCT to be answered. However, as this design is not widely used, there is currently no standard guidance for those carrying out open-cohort cluster RCTs and there remain questions about how statisticians should work out the sample size needed and how to best analyse the data. This is a barrier to using an open-cohort design.In this study, we will address these barriers. We will review the literature on open-cohort RCTs. We look at the statistical properties of open-cohort RCTs by reanalysing data from our DCM trial and from two further RCTs we identify in the literature review. This will include how to work out the sample size, how to analyse the data and advice for researchers on the situations when an open-cohort RCT will be the best choice design. We will also consult researchers who carry out RCTs, through expert group meetings and on-line surveys to make sure our findings are seen as acceptable by those who will use them. We will develop practical guidelines about open-cohort cluster RCTs that can be used by researchers who are planning to carry future trials. These will be shared through academic papers, conferences and briefing documents for research funders.

随机临床试验(RCT)是一种被接受的测试干预措施的研究方法。招募的参与者通常被随机分配到接受干预或对照组。一开始就进行计算，以计算出需要多少参与者才能得到准确的结果。然而，疗养院或医院病房的许多干预措施是在环境(单位、病房或疗养院)级别进行的。这意味着疗养院或医院病房以及其中的个人参与者被随机分成一组。这称为集群RCT。在分组随机对照试验中，分组的数量以及参与者的数量都很重要。申请者目前正在进行分组随机对照试验，以观察一种名为痴呆症护理映射(DCM)的干预措施在减少痴呆症患者焦虑方面的有效性。工作人员使用DCM来确定他们可以在疗养院做出的改进。因此，当使用DCM时，任何住在疗养院的居民都可能受益。有两种公认的方法来设计集群随机对照试验。封闭队列设计在一段时间内跟踪相同的人，在试验开始、结束时收集他们的数据，有时在试验的中间时间点收集数据。这使得能够分析干预对个人和群体的影响。我们的DCM试验使用此设计。疗养院、医院和其他环境中的一个问题是，由于出院/搬家或死亡，个人的流动率很高。其他个人也在这段时间内进入环境，并接受干预，但不包括在随机对照试验中。随机对照试验的时间越长，退学的人就可能越多。为了管理这一点，必须在区域工作队开始时招募更多的集群和个人，以确保在结束时仍有足够的个人在那里。这使得这项研究非常昂贵。在我们的DCM试验中，到我们最后16个月的随访时，大约50%的居民将离开试验，主要是由于死亡。横截面设计是目前的替代方案。该设计在随机对照试验开始和结束时收集集群中个人的数据。它不跟踪个人随时间的变化，而是假设每个数据收集点的个人都不同。这再次减少了可以在以后的时间点招募的个人数量。一个可以使用的不同设计是开放队列群随机对照试验。在这个设计中，所有新的符合条件的个体都被招募，并在随机之后连续或在设定的数据收集时间点收集关于他们的数据。这种设计的潜在优势是：它可能更经济，因为需要招募的集群更少，(Ii)灵活，因为它可以在整个随机对照试验中回答与暴露于干预措施的个人有关的研究问题。然而，由于这一设计没有得到广泛应用，目前没有对那些进行开放队列分组随机对照试验的人提供标准指导，关于统计员应该如何计算出所需的样本量以及如何最好地分析数据的问题仍然存在。这是使用开放队列设计的障碍。在这项研究中，我们将解决这些障碍。我们将回顾关于开放队列随机对照试验的文献。我们通过重新分析来自我们的DCM试验和我们在文献回顾中确定的另外两个随机对照试验的数据，来查看开放队列随机对照试验的统计特性。这将包括如何计算样本量，如何分析数据，以及在开放队列随机对照试验将是最佳选择设计的情况下为研究人员提供建议。我们还将通过专家组会议和在线调查，征询进行随机对照试验的研究人员的意见，以确保我们的发现被使用这些研究的人视为可接受的。我们将制定关于开放队列分组随机对照试验的实用指南，供计划进行未来试验的研究人员使用。这些将通过学术论文、会议和为研究资助者提供的简报文件共享。