Trial recruitment decision-making: crucial but not evidence-based
Brighton, UK

Speaker: Shaun Treweek

This is a talk at the International Clinical Trials Methodology Conference (ICTMC), Brighton, UK, 6th – 9th October 2019.  Venue is the Hilton Brighton Metropole.

Parallel Session 9B – Challenges With Trial Recruitment 4: Towards Better Practice
Wednesday, Oct 9, 2019
8:45 AM – 9:50 AM



Shaun Treweek, Marie Pitkethly, Jonathan Cook, Cynthia Fraser, Elizabeth Mitchell, Frank Sullivan, Catherine Jackson, Tyna K Taskila, Heidi Gardner.


Evidence-based trial recruitment strategies would benefit patients, trialists and health research.  This talk summarises the 2018 update to the Cochrane review of strategies to improve recruitment to randomised trials.


Randomised evaluations of recruitment interventions embedded within a host randomised trial were eligible.  Six databases, including MEDLINE were searched.  Abstract screening, full text assessment, data extraction, risk of bias and GRADE assessments were conducted independently by two reviewers.   Risk difference and 95% confidence interval (CI) were calculated.  Meta-analysis was done where appropriate.  Protocols for evaluation of interventions considered priorities for replication studies were developed.  


24,432 abstracts were screened and 68 studies included, involving over 74,000 people.  We found 72 interventions; only three were GRADE High certainty:

  1. Open trials rather than blinded, placebo trials. Risk difference: 10% (95% CI 7% to 13%).
  2. Telephone reminders to people who do not respond to a postal invitation. Risk difference:  6% (95% CI 3% to 9%).
  3. Using a bespoke, user-tested participant information leaflet. Risk difference: 1% (95% CI -1% to 3%).

Eight other interventions had GRADE Moderate certainty, certainty generally being reduced because of only having a solitary evaluation.   Only seven interventions had been evaluated more than once and the uncertainty around most interventions in the review has not changed in a decade.  Further evaluations of telephone reminders, text messages and financial incentives were considered priorities and evaluation protocols provided as part of the review.   


The evidence base to support trial recruitment is poor.  Where evaluations have been done a combination of design flaws, solitary evaluations and poor precision mean we can conclude little from the bulk of them.  Prioritised and coordinated approaches to generating recruitment evidence are needed to avoid another decade without progress.

Start typing and press Enter to search