A protocol for a systematic review of non-randomised evaluations of strategies to increase participant retention to randomised controlled trials

Abstract

BackgroundRandomised control trials are regarded as the gold standard for evaluating the effectiveness and efficacy of healthcare interventions with thousands of trials published every year. Despite significant investment in infrastructure, a staggering number of clinical trials continue to face challenges with retention. Dropouts could lead to negative consequences—from lengthy delays to missing data that can undermine the results and integrity of the trial.Summarising evidence from non-randomised evaluations of retention strategies could provide complementary information to randomised evaluations that could guide trialists to the most effective ways of increasing retention of participants in clinical trials.MethodsThe following electronic databases will be searched for relevant studies: EMBASE, MEDLINE, the Cochrane Controlled Trials Register, and Cochrane Methodology Register and the search will be limited to English-published studies during the last 10 years to increase relevance to current trials. Non-randomised studies (observational studies) including a comparison of two or more strategies to increase participant retention in randomised trials or comparing one or more strategies with no strategy will be included. The primary outcome will be the proportion of participants remained at the primary analysis as determined in each retention study.DiscussionThis review aims to gather and evaluate evidence on the effect of retention strategies examined in non-randomised studies. It is imperative to collect evidence from obseravational studies to infer whether or not these studies could be considered a practical way to complement or even replace a broadly favourable randomised design. If we find that non-randomised studies to be included in this review are of high quality with adequate control of biases, we will recommend to trialists and others not to rely exclusively on randomised studies and to give meticulous attention to the plentiful evidence that can be obtained from non-randomised studies. Should the results of this review suggest that evaluating retention strategies in observational studies provides insufficient evidence to trialists planning their retention strategies, we will be able to say that there is little point in conducting non-randomised studies and that they would do better to invest their time and resources in a randomised evaluation if possible. Where a non-randomised study design is chosen, the review authors will offer recommendations to trialists and others regarding how to ensure that these studies are conducted in a way that can minimise the risk of bias and increase confidence in the findings.Systematic review registrationPROSPERO 2017:CRD42017072775.Electronic supplementary materialThe online version of this article (10.1186/s13643-018-0696-7) contains supplementary material, which is available to authorized users.

Rates of retention of persons with a mental health disorder in outpatient smoking cessation and reduction trials, and associated factors: protocol for a systematic review and meta-analysis

“…Illustrating a consensus regarding the need to consider and address the issue of low retention in clinical and health behaviour trials: the inclusion of items on participant retention in the Consolidated Standards of Reporting Trials (CONSORT) statement,28 29 and prioritisation of trial methodology research to develop novel approaches to increase retention in randomised trials 30 31. In addition, the emergence of recent systematic reviews examining retention rates in health behaviour studies32–36 and publication of retention data from high quality randomised trials37–39 indicates increased interest in the topic of retention and a recognition of its importance.…”

How can technology support ageing in place in healthy older adults? A systematic review

“…To define RCT and CCT as inclusion criteria allows authors to embrace in their review only papers that followed a strict method for reducing certain sources of bias when testing the effectiveness of new treatment, reducing spurious causality [ 31 ]. The applied methodology of RCT is often referred to as the gold standard for evaluating effectiveness and efficacy of healthcare interventions [ 32 – 34 ]. As a result, reviewers are capable of presenting papers that have accomplished the most reliable form of healthcare-outcome evidence in the hierarchy of evaluation that could influence healthcare practice [ 35 ].…”

What are the most important unanswered research questions in trial retention? A James Lind Alliance Priority Setting Partnership – The PRioRiTy II (Prioritising Retention in Randomised Trials) Study

“…The consensus meeting culminated in a plenary session involving all the stakeholders. This finalised the ordering of the questions, created the Top 10 list shown in Table 4, and ranked the remaining questions (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)Appendix 2). All are available online at www.priorityresearch.ie.…”

“…Although, where appropriate, the JLA facilitators and some group participants did point out the difference, it is possible that some people chose to interpret and therefore rank the questions on that basis. In the final ordered question list, the questions ranked in the bottom six positions (16)(17)(18)(19)(20)(21) all featured examples. This framing effect is known to be a problem in survey research [19].…”