Parkinson disease (PD) is highly prevalent among neurodegenerative diseases, affecting a diverse patient population. Despite a general willingness of patients to participate in clinical trials, only a subset of patients enroll in them. Understanding the barriers to trial participation will help to alleviate this discrepancy and improve trial participation. Underrepresented minorities, older patients, and patients with more medical comorbidities in particular are underrepresented in research. In clinical trials, this has the effect of delaying trial completion, exacerbating disparities, and limiting our ability to generalize study results. Efforts to improve trial design and recruitment are necessary to ensure study enrollment reflects the diversity of patients with PD. At the trial design level, broadening inclusion criteria, attending to participant burden, and focusing on trial efficiency may help. At the recruitment stage, increasing awareness, with traditional outreach or digital approaches; improving engagement, particularly with community physicians; and developing targeted recruitment efforts can also help improve enrollment of underrepresented patient groups. The use of technology, for virtual visits, technology-based objective measures, and community engagement, can also reduce participant burden and increase recruitment. By designing trials to consider these barriers to trial participation, we can improve not only the access to research for all our patients but also the quality and generalizability of clinical research in PD.
Keywords: Clinical trial; Parkinson disease; barriers; diversity; recruitment; trial design.