Guide on Selection of Optimal Motivational Themes for Use in a Clinical Trial Recruiting Black US Adults: Survey Study.

Demographic factors played a more significant role than motivational themes in predicting advertisement effectiveness in recruiting Black adults to a hypertension-focused clinical trial.

• The study used an online survey with 829 self-identified Black adults in the United States.
• A between-subject design tested 4 literature-derived motivational themes: contribution to science, helping the community, lowering blood pressure, and access to perks (US $500 worth of groceries or equivalent cash).
• Outcomes assessed were advertisement appeal, willingness to participate, and willingness to recommend clinical trial participation to others.
• Cumulative link mixed models were used to analyze the data.

Adults aged 40-59 years and individuals diagnosed with high blood pressure were more likely to find the advertisements appealing and express willingness to participate.

• Age group (40-59 years) was identified as a significant demographic predictor of advertisement appeal and willingness to participate.
• Having a diagnosis of high blood pressure was also associated with greater advertisement appeal and willingness to participate.
• These findings support demographic targeting over generic motivational messaging.

Urban residents engaged more with the clinical trial advertisements compared to those in suburban or rural areas.

• Geographic location (urban vs. suburban or rural) was identified as a significant demographic factor influencing advertisement engagement.
• This finding suggests that geographic targeting is an important component of effective recruitment strategies for Black adults.

Participants with liberal or conservative political views were more willing to participate in the clinical trial compared to those with moderate political views.

• Liberal political views were associated with greater willingness to participate (OR 1.37, 95% CI 1.01-1.85; P=.04).
• Conservative political views were also associated with greater willingness to participate (OR 1.62, 95% CI 1.09-2.40; P=.02).
• Both comparisons were relative to participants with moderate political views.

The 'lowering my blood pressure' motivational theme was less effective among individuals who distrusted health care institutions and also reduced willingness to recommend the trial.

• Among individuals who distrusted health care institutions, the 'lowering my blood pressure' theme was associated with reduced willingness to participate (OR 0.40, 95% CI 0.16-0.97; P=.04).
• This theme also reduced willingness to recommend the trial among those with lower trust (OR 0.36, 95% CI 0.15-0.85; P=.02).
• Unexpectedly, higher trust levels were also associated with lower willingness to participate when exposed to this theme (OR 0.41, 95% CI 0.17-0.98; P=.04).

The online survey methodology was identified as a rapid, scalable tool for pretesting clinical trial recruitment strategies.

• The authors note this methodology 'offers researchers a rapid, scalable tool for pretesting recruitment strategies.'
• The authors recommend it should 'complement rather than replace community engagement.'
• The survey recruited 829 self-identified Black adults in the United States using an online platform.

Black adults in the United States are underrepresented in cardiovascular clinical trials, contributing to cardiovascular health disparities.

• The authors attribute underrepresentation partly to 'unique historical events, discriminatory practices, and practical obstacles' experienced by the Black adult US population.
• The study was motivated by the premise that improved understanding of motivations could 'lead to more effective clinical trial recruitment and help mitigate these cardiovascular health disparities.'
• The trial was hypertension-focused, targeting a condition with known disparate impact on Black adults.