Interest in clinical trial participation in Parkinson's disease: Insights from a nationwide registry

Objective To compare (socio-)demographic, clinical, and functional characteristics of Parkinson's disease (PD) patients interested in clinical trial participation with those who are not. Background Representative recruitment is essential for clinical trials. Identifying factors associated with interest in participation may help tailor trial designs and recruitment strategies. Methods We analyzed cross-sectional data from a nationwide PD registry in Austria. Participants were dichotomized according to interest in clinical trial participation at inclusion, and group differences were statistically determined. Predictors of interest were selected using logistic regression with LASSO regularization. Results Among 543 PD patients, 395 (72.7%) expressed interest in clinical trial participation. Interested patients were younger (67.65 ± 10.16 vs. 72.76 ± 9.08 years, p < 0.001), had a shorter disease duration (9.24 ± 6.81 vs. 11.68 ± 8.64 years, p = 0.003), and less advanced disease, reflected by lower Hoehn and Yahr-stages (median 2.00 ± 1.00 vs. 3.00 ± 1.00, p < 0.001) and MDS-UPDRS-scores (all p < 0.001). Interested patients were also less likely to be functionally dependent (36.2% vs. 58.5%, p < 0.001), receive care allowance (24.8% vs. 41.9%, p < 0.001), or live in care facilities (2.8% vs. 10.1%, p = 0.001). Sex and motor fluctuations did not differ (all p > 0.085). LASSO regression identified absence of postural instability and dementia, younger age, and not being widowed as the strongest predictors of positive interest to participate in clinical trials. Conclusions Interest in clinical trial participation among PD patients is related to younger age, lower disease burden, and greater functional independence. Patients with more advanced disease and disability appear less interested, highlighting potential challenges for designing and interpreting clinical trials.