Participant recruitment and retention in longitudinal preconception randomized trials: lessons learnt from the Calcium And Pre-eclampsia (CAP) trial

Abstract

BackgroundThe preconception period has the potential to influence pregnancy outcomes and randomized controlled trials (RCTs) are needed to evaluate a variety of potentially beneficial preconception interventions. However, RCTs commencing before pregnancy have significant participant recruitment and retention challenges. The Calcium And Pre-eclampsia trial (CAP trial) is a World Health Organization multi-country RCT of calcium supplementation commenced before pregnancy to prevent recurrent pre-eclampsia in which non-pregnant participants are recruited and followed up until childbirth. This sub-study explores recruitment methods and preconception retention of participants of the CAP trial to inform future trials.MethodsRecruiters at the study sites in Argentina, South Africa and Zimbabwe completed post-recruitment phase questionnaires on recruitment methods used. Qualitative data from these questionnaires and quantitative data on pre-pregnancy trial visit attendance and pregnancy rates up to September 2016 are reported in this paper. RStudio (Version 0.99.903 https://www.rstudio.org) statistical software was used for summary statistics.ResultsBetween July 2011 and 8 September 2016, 1354 women with previous pre-eclampsia were recruited. Recruitment took 2 years longer than expected and was facilitated mainly through medical record/register and maternity ward/clinic-based strategies. Recruiters highlighted difficulties associated with inadequate medical records, redundant patient contact details, and follow-up of temporarily ineligible women as some of the challenges faced. Whilst the attendance rates at pre-pregnancy visits were high (78% or more), visits often occurred later than scheduled. Forty-five percent of participants became pregnant (614/1354), 33.5% (454/1354) within 1 year of randomization.ConclusionsIn preconception trials, both retrospective and prospective methods are useful for recruiting eligible women with certain conditions. However, these are time-consuming in low-resource settings with suboptimal medical records and other challenges. Trial planners should ensure that trial budgets cover sufficient on-site researchers with pre-trial training, and should consider using mobile phone and web-based electronic tools to optimize recruitment and retention. This should lead to greater efficiency and shorter trial durations.Trial registrationPan-African Clinical Trials Registry, Registration Number: PACTR201105000267371. The trial was registered on 6 December 2016.

How to improve participant compliance and retention in clinical trials：A Scoping Review

“…People with high-income will have higher compliance and retention [9-11,15-18,28,29,31,36,37,40,45,48,49,58,59,61-63,65,71,72,80,81,85,87- Trust for the trial The more trust, the higher compliance and retention [9,11,12,14,[16][17][18][19]27,29,31,32,36,38,41,45,47,48,53,55,58,61,63,64,69,71,73,79,[81][82][83]…”

“…People who have positive attitude to disease may have higher compliance and retention [16,35,36,45,74,97,109,118,119,132,142,145,146,173,178,189] .…”

“…The phase of protocol design Develop simple and convenient research or questionnaire design to make them conform to the patient's lifestyle [16,19,20,[22][23][24]26,[33][34][35]44,45,49,52,54,56,66,69,71,73,74,80,88,89,92,97,105,111,114,117,132,136,143,150,153,156,157,162,165,166,176,177,179,189] 45 /182 Training researchers in advance (such [9,19,26,31,38,53,54,63,66,,74,80,90,113,120,130 Determining the frequency of follow-up reasonably [44,45,56,58,…”

“…Providing multiple forms of research documents (online or on-site) [16,39,104,153] 4/182 Reducing the number of research files [ Setting up a methodology team to explore measures to improve compliance [80,100,117] 3/182 Making full use of predictive factors [53 The phase of recruitment and informed consent Full implementation of informed consent(safety concerns, effect, study protocol, the time they may take,etc) [14,18,19,22,25,46 54/182 Expanding the channels of recruitment [11,12,13,25,27,32,35,46,47,48,49 188,189] Pre-compliance assessment [14,22,25,[33][34][35]45,46,51,55,56,64,66,67,71,72,[78][79][80][91][92][93]97,108,113,114,125,134,141,147,…”

“…Paying attention to the changes on participants' psychological and building good relationships [6,9,17,19,20,22,25,26,29,32,35,36,[38][39][40]45,46,50,52,53,55,57,61,63,64,69,74,78,79,83,85,87,88,90,[92][93][94][95][96][97]101,103,104,107,[112][113][114]120,121,[125][126][127]…”