Effect of different recruiter attire on trial participation in Lesotho: a randomized study within a trial

Effective participant recruitment is central to generating evidence in randomized controlled trials. Clinical trials have increased in Lesotho, but research processes are rarely assessed in this setting. The recruiter's attire is a modifiable factor that may influence a patient's decision to participate in a trial upon being approached. In healthcare domains, white coats convey clinical authority over patients seeking help for their health problems. This study aimed to determine the effect of clinical trial recruiter attire on trial participation rates in a peri-urban district outpatient clinic in Lesotho.

A cluster-randomized study within a trial (SWAT) was conducted with two recruiters, who were daily randomized to wear white coats or casual attire. The SWAT was embedded in a vignette-based trial testing the impact of social endorsement of a new treatment on patients' uncertainty attitudes, and its data source was the host trial's prescreening logs. The primary outcome of the SWAT was the participation rate, defined as the rate of patients who accepted participation in the host trial out of those approached. Negative binomial mixed effect regression was used to model attire and recruiter effects on participation with day-based random effects.

Overall, 70% of patients accepted participation in the host trial out of 682 approached for recruitment. Among these, 71% of 374 patients approached by a recruiter wearing white coats and 68% of 308 patients approached by a recruiter in casual attire accepted trial participation (adjusted incidence rate ratio [aIRR], 1.03; 95% confidence interval [CI], 0.86-1.24; ref = casual). The older male recruiter yielded lower participation compared to the younger female recruiter (aIRR = 0.86; 95% CI = 0.69-0.98). No interaction effects were observed between attire conditions and recruiters.

We found no evidence that attire is associated with improved participation rates in Lesotho. Further investigations on other recruiter characteristics alongside trials may identify meaningful targets to improve clinical trial recruitment in this setting.

The host trial and its SWAT protocols were preregistered in OSF.io ( N6xc2 ) and registered in ClinicalTrials.gov (NCT06246058). February 07 2024.