How to improve participant compliance in clinical trials: A Scoping Review of process factors

Abstract

Background The reliability of results can be compromised when subsets of participants who remain on a study differ from those who drop out. Although recent studies have investigated approaches for improving compliance, there has been very little investigation of process factors, regardless of the type of literature and the publication date. factors that may influence how and why compliance may be successful (or not). Aim To identify process factors that may influence participant compliance retention in clinical trials, and potential approaches to improve the compliance, from published studies, to facilitate future design and implementation of trials. Methods Six databases and two clinical trial registries were searched on November 29, 2019. Surveys, interviews, retrospective data analyses, theoretical research, reviews and clinical studies aiming at investigating factors influencing participant compliance and potential approaches for improving compliance retention were included. Data synthesis followed an iterative process to develop a list of process factors and potential retention approaches. Results were analysed descriptively, including visualization using word cloud. Results 181 publications were included in this review, composed of 58 retrospective analysis of RCTs based on 1,132 clinical trials with 177804 participants, 27 implementation researches, 22 theoretical researches, 20 interviews, 18 surveys, 17 randomized controlled trials, 8 literature reviews, 5 systematic review and meta analysis, 3 mixed methods researches, 2 case report and 1 cohort study. We identified 70 process factors that may affect the compliance. The most commonly addressed factors were age, education, economy, trust in clinical trials, supporting from surrounding people, safety concerns and effectiveness. We found 44 potential approaches to improve compliance. Approaches reported most frequently were that researchers should pay attention to the changes on participants' psychological condition, try their best to build good relationships, provide some compensation and educate the participants about compliance. Conclusion These factors that may affect the compliance can help researchers predict participants who are less likely to adhere and develop screening tools to find efficiently their suitable participants. These potential approaches that may improve the compliance provide suggestions for improving compliance.