Factors associated with willingness to participate in a vaccine clinical trial among elderly Hispanic patients

A population specific understanding of barriers and facilitators to participation in clinical trials could improve recruitment of elderly and minority populations. We investigated how prior exposure to clinical trials and incentives were associated with likelihood of participation in a vaccine clinical trial through a questionnaire administered to 200 elderly patients in an academic general internal medicine clinic. Wilcoxon signed rank sum test compared likelihood of participation with and without monetary incentives. Logistic regression evaluated characteristics associated with intent to participate in an influenza vaccine trial, adjusted for age, gender, language, and education history. When asked about likelihood of participation if there was monetary compensation, there was a 12.2% absolute increase in those reporting that they would not participate, with a significant difference in the distribution of likelihood before and after mentioning a monetary incentive (Wilcoxon signed rank test, p = 0.001). Those with previous knowledge of clinical trials (54.4%) were more likely to report they would participate vs. those without prior knowledge (OR 2.5, 95% CI [1.2, 5.2]). The study highlights the importance of pre-testing recruitment materials and incentives in key group populations prior to implementing clinical trials.