Abstract Body (Do not enter title and authors here): Background
Despite bearing a disproportionately high burden of cardiovascular disease, Black adults remain grossly underrepresented in clinical trials. Culturally tailored, digital recruitment strategies such as tailored websites using specific thematic messaging may improve trial representativeness, but the effectiveness of these themes remains unclear.

Objectives
We sought to evaluate the effectiveness of different motivational themes, within a digital recruitment website, on engagement and clinical trial sign-up rates among Black adults. We hypothesized that non-standard themes, especially the community well-being-focused theme, would increase engagement in a cardiovascular clinical trial compared to standard websites.

Methods
We implemented digital recruitment for GoFresh, a randomized cardiovascular clinical trial testing the effect of a DASH diet grocery intervention on blood pressure among Black adults. Website themes were derived from pre-developed motivational categories. These themes included (1) contribution to science (standard), (2) community well-being, (3) personal blood pressure improvement, and (4) access to perks (groceries or cash). A/B randomization directed study site visitors to 1 of each theme randomly between June and December 2024 (Figure). The Matomo web analytics platform captured visitor behavior, including visits, pageviews, time on site, and sign-ups to complete trial pre-screening. We compared themes using Welch’s t-tests to estimate mean differences in metrics between the control (standard science theme) and each variant. Statistical significance was defined as two-tailed P<0.05.

Results
There were 11,902 visitors over 6 months (Table). The community-focused message yielded the most trial sign-ups. All alternative variations led to significantly higher pageviews per visitor compared to the science-based message (≥67% increase, P<0.001). When comparing all four themes, the community-themed message also yielded a modestly higher average time spent on site (mean: 1 min 4 sec; 8.1% detected effect; P≤0.05).

Conclusion
Tailored digital messages emphasizing community and health benefits significantly improved engagement and trial interest. Digital strategies employing culturally tailored messages may enhance equitable recruitment within cardiovascular disease research, but future work should examine eligibility, screening efficiency, and randomization rates.