JMIR Publications

ABSTRACT

Background:

Black adults in the United States (US) face significant cardiovascular health disparities, which are likely exacerbated by the underrepresentation of Black adults in cardiovascular clinical trials. The Black US population has experienced unique historical events, discriminatory practices, and practical obstacles that might contribute to this underrepresentation in clinical trials. Improved understanding of motivations that encourage or discourage participation in cardiovascular clinical trials can lead to more effective clinical trial recruitment and help mitigate these cardiovascular health disparities.

Objective:

Using an online survey, determine which motivational themes in clinical trial recruitment advertisements are most effective in encouraging Black adults to participate in a hypertension-focused trial. We also explored how trust in healthcare and various demographic factors influenced their decision to participate.

Methods:

We conducted an online survey with 829 self-identified Black adults in the US, using a between-subject design to test four literature-derived motivational themes in clinical trial recruitment advertisements: (1) contribution to science, (2) helping the community, (3) lowering blood pressure, and (4) access to perks ($500 worth of groceries or an equivalent cash amount). We assessed advertisement appeal, willingness to participate, and willingness to recommend clinical trial participation to others using Cumulative Link Mixed Models (CLMM).

Results:

Demographic factors played a more significant role than motivational themes in predicting advertisement effectiveness. Adults aged 40-59 and individuals diagnosed with high blood pressure were more likely to find the advertisements appealing and express willingness to participate. Urban residents engaged more with the advertisements compared to those in suburban or rural areas. Participants with liberal (OR: 1.37, 95% CI: 1.01-1.85, p = 0.044) and conservative (OR: 1.62, 95% CI: 1.09-2.40, p = 0.018) political views were more willing to participate in the clinical trial compared to those with moderate views. However, the “Lowering my blood pressure” theme was less effective among individuals who distrusted healthcare institutions (OR: 0.40, 95% CI: 0.16-0.97, p = 0.042) and also reduced willingness to recommend the trial (OR: 0.36, 95% CI: 0.15-0.85, p = 0.020). Additionally, higher trust levels were unexpectedly associated with lower willingness to participate when exposed to this theme (OR: 0.41, 95% CI: 0.17-0.98, p = 0.044).

Conclusions:

This study contributes new empirical evidence on the science of inclusive trial recruitment and provides an evidence-based approach to using recruitment advertisements to improve clinical trial participant diversity.