Motivational themes in digital advertisements enhance recruitment efficiency in cardiovascular trials

Successful trial recruitment depends on balancing initial interest with participants' commitment and eligibility. It is uncertain how different motivational advertisement themes affect recruitment of interested and eligible trial participants.

The GoFresh trials examined how healthy groceries affect blood pressure among Black adults from Boston healthy food priority areas. Using Facebook's "A/B testing" feature, users 18 years and older in eligible ZIP codes were randomly shown one of four digital advertisement themes-science volunteerism, study incentives, blood pressure reduction, or wellness in the Black community-between November 2023 and December 2024. We tracked Facebook and website analytics by theme. 'Interest' was defined as submission of an online interest form. 'Commitment' as visit no-show rates, and 'Eligibility' as qualification following the in-person visit. The 'number needed to screen' was calculated as 1 divided by the proportion of inquiries who were eligible.

Advertisements reached 603,418 Facebook users and generated 32,168 clicks, 264 inquiries, 73 scheduled visits, and 23 eligible participants. The community theme generated the highest inquiry engagement rate (54%) but lower commitment (8 no-shows) and the highest number needed to screen (17). The blood pressure theme had the lowest inquiry engagement rate (32%) but yielded the highest commitment (2 no-shows) and the lowest number needed to screen (8).

Beyond generating study interest, motivational themes may select for participants with varying degrees of commitment and eligibility, which could affect the cost-effectiveness of recruitment and long-term retention. These findings have important implications for timely and representative recruitment for cardiovascular trials.

URL: https://clinicaltrials.gov/; Unique Identifier: NCT05121337 & NCT05393232.