Patient Experience in Early-Stage Parkinson’s Disease: Using a Mixed Methods Analysis to Identify Which Concepts Are Cardinal for Clinical Trial Outcome Assessment

INTRODUCTION: Qualitative research on patient experiences in early-stage Parkinson’s disease (PD) is limited. It is increasingly acknowledged that clinical outcome assessments used in trials do not fully capture the range of symptoms/impacts that are meaningful to people with early-stage PD. We aimed to conceptualize the patient experience in early-stage PD and identify, from the patient perspective, those cardinal symptoms/impacts which might be more useful to measure in clinical trials. METHODS: In a mixed-methods analysis, 50 people with early-stage PD and nine relatives were interviewed. Study design and results interpretation were led by a multidisciplinary group of patient, clinical, regulatory, and outcome measurements experts, and patient organization representatives. Identification of the cardinal concepts was informed by the relative frequency of reported concepts combined with insights from patient experts and movement disorder specialists. RESULTS: A conceptual model of the patient experience of early-stage PD was developed. Concept elicitation generated 145 unique concepts mapped across motor and non-motor symptoms, function, and impacts. Bradykinesia/slowness (notably in the form of “functional slowness”), tremor, rigidity/stiffness, mobility (particularly fine motor dexterity and subtle gait abnormalities), fatigue, depression, sleep/dreams, and pain were identified as cardinal in early-stage PD. “Functional slowness” (related to discrete tasks involving the upper limbs, complex mobility tasks, and general activities) was deemed to be more relevant than “difficulty” to patients with early-stage PD, who report being slower at completing tasks rather than encountering significant impairment with task completion. CONCLUSION: Patient experiences in early-stage PD are complex and wide-ranging, and the currently available patient-reported outcome (PRO) instruments do not evaluate many early-stage PD concepts such as functional slowness, fine motor skills, and subtle gait abnormalities. The development of a new PRO instrument, created in conjunction with people with PD, that fully assesses symptoms and the experience of living with early-stage PD, is required. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40120-022-00375-3.