Path Analysis of RCT Recruitment: Secondary Analysis of Results from a Systematic Review.

We examine recruitment processes for 71 pragmatic and comparative effectiveness trials identified in a systematic review, using path analysis to examine rates of refusal to screen, test, and consent to trial participation. Our analysis suggests that refusal rates might be on net slightly higher if potential subjects are screened or asked to undergo physical eligibility tests, but this was not significant in our sample of trials (p = .11 by Mann-Whitney test). We find that rates of refusing to provide informed consent are much lower for trials in which subjects have agreed to screening or testing (odds ratio = 0.40, Wilcoxon rank-sum z = 2.67, p = .008). We also observe that the overwhelming majority of trials examined secured consent after determining eligibility, even in trials involving screening or testing activities. The ethical implications and areas for future research are discussed.

Refusal rates and waivers of informed consent in pragmatic and comparative effectiveness RCTs: A systematic review.

BACKGROUND: Pragmatic and comparative effectiveness randomized controlled trials (RCTs) aim to be highly generalizable studies, with broad applicability and flexibility in methods. These trials also address recruitment issues by minimizing exclusions. The trials may also appeal to potential subjects because of lower risk and lower burdens of participation. We sought to examine rates of refusal and uses of waivers of informed consent in pragmatic and comparative effectiveness RCTs. METHODS: A systematic review of pragmatic and comparative effectiveness RCTs performed wholely or in part in the United States and first published in 2014 and 2017. RESULTS: 103 studies involving 105 discrete populations were included for review. Refusal data was collected for 71 RCTs. Overall, studies reported an average rate of 31.9% of potential subjects refused participation; on an individual basis, 38.4% of people asked to take part refused at some point during recruitment. 23 trials (22%) were performed, at least in part, with a waiver of informed consent, 7 (30%) of which provided any form of notice to subjects. CONCLUSIONS: Overall refusal rates for pragmatic and comparative effectiveness RCTs appear roughly the same as other types of research, with studies reporting about a third of people solicited for participation refuse. Moreover, informed consent was waived in 22% (95% Binomial exact Confidence Interval 13.9-30.5%) of the trials, and further study is needed to understand when waivers are justified and when notice should be provided.