Experiences with recruitment and retention of adolescents and emerging adults in a weight loss intervention trial.

Background/aims: Efficient and effective participant recruitment is key for successful clinical research. Adolescent and emerging adult recruitment into clinical trials can be particularly challenging, especially when targeting underrepresented groups. This study aimed to determine the most successful recruitment strategies from those employed during a pediatric trial testing the efficacy of a behavioral intervention on adiposity and cardiovascular disease risk.

Methods: We determined the effectiveness, cost, and diversity of the final research population by each recruitment method utilized in the EMPower trial, a randomized clinical trial designed to test the effect of a technology-delivered behavioral Healthy Lifestyle intervention on adiposity, blood pressure, and left ventricular mass among adolescents and emerging adults with overweight or obesity. Effectiveness was determined by respondent yield (RY; number of respondents/number contacted), scheduled yield (SY; number scheduled for a baseline visit/number of respondents), enrollment yield (EY; number enrolled/number of respondents), and retention (number completed/number enrolled). Cost-effectiveness of each recruitment method was calculated and demographics of participants recruited via each method was determined.

Results: A minimum of 109,314 adolescents and emerging adults were contacted by at least one recruitment method (clinic, web-based, postal mailing, electronic medical record (EMR) messaging) leading to 429 respondents. The most successful strategies in terms of RY were clinic-based recruitment (n = 47, 61% RY), community web-postings (n = 109, 5.33% RY), and EMR messaging (n = 163, 0.99% RY); however, website, postal mailings, and EMR recruitment led to more successful SY and EY. Postal mailings were the most costly strategy to employ (US$3261/completed participant) with EMR messaging the second most costly (US$69/completed participant). Community web-postings were free of charge. Clinic-based recruitment did not add additional costs, per se, but did require a substantial amount of personnel time (63.6 h/completed participant). Final cohort diversity primarily came from postal mailings (57% Black) and EMR messages (50% female).

Conclusion: Electronic medical record messaging and web-based recruitment were highly successful and cost-effective strategies in a pediatric clinical trial targeting adolescents and emerging adults, but was less successful in recruiting a diverse cohort. Clinic recruitment and postal mailings, despite being costly and time-consuming, were the strategies that enrolled a greater proportion of underrepresented groups. While online forms of trial recruitment are growing in popularity, clinic-based recruitment and non-web-based strategies may be required to ensure participant diversity and representation.