Trajectories and Predictors of Activity Participation Among People with Parkinson Disease: A 3-Year Longitudinal Study.

The sample was homogeneous (mostly Caucasian, highly educated, and in early disease stages), which limits generalizability to more diverse or advanced PD populations. Attrition occurred (26 dropped out), and reasons for dropout were not documented, leaving open the possibility that systematic attrition biased the results. The study measured the number of activities performed but not the frequency, intensity, duration, or quality of participation, so it may miss nuanced changes in how people engage. The unexpected negative association between cognition and social participation conflicts with univariate results and may be due to statistical issues like multicollinearity. The study may have been underpowered to detect small effects despite exceeding recommended sample size thresholds for multilevel modeling.

The investigators have no financial or nonfinancial disclosures to make in relation to this project.

Do not assume that stable overall participation means patients are maintaining their quality of life or that those with mild symptoms are safe. Patients with lower depressive symptoms actually showed a decrease in participation over time, indicating that early-stage or mildly symptomatic patients still require active monitoring and support to maintain engagement.