A Patient-Centered Conceptual Model of Symptoms and Their Impact in Early Parkinson's Disease: A Qualitative Study

Background: Individuals with Parkinson's disease (PD) develop a significant disease burden over time that contributes to a progressive decline in health-related quality of life. There is a paucity of qualitative research to understand symptoms and impacts in individuals with early-stage PD (i.e., Hoehn and Yahr stage 1-2 and <= 2 years since diagnosis). Objective: The collection of qualitative data to inform the selection of clinical outcome assessments for clinical trials is advocated by regulators. This patient-centered, multistage study sought to create a conceptual model of symptoms and their impact for individuals with early-stage PD. Methods: Symptoms and impacts of PD were gathered from a literature review of qualitative research, a quantitative social media listening analysis, and qualitative patient concept elicitation interviews (n = 35). Clinical experts provided input to validate and finalize the concepts. Results: The final conceptual model consisted of 27 symptoms categorized into 'motor' or 'non-motor' domains, and 39 impacts divided into five domains. Most frequently reported symptoms in early-stage PD were 'tremors' (89%), 'stiffness and rigidity', and 'fatigue' (69%, both). Most frequently reported impacts included 'anxiety' (74%), 'eating and drinking' (71%), followed by 'exercise/sport' and 'relationship with family/family life' (66%, both). Conclusion: This study provides initial insights relating to the symptom and impact burden of early-stage PD patients. The conceptual model can be used to help researchers to develop and select optimal patient-centered outcomes to measure treatment benefit in clinical trials. These findings could inform future qualitative research and the development of outcomes specifically for early-stage PD patients.