Parkinson's disease-subjective cognitive decline and health-related quality of life

Background: Parkinson's disease-subjective cognitive decline (PD-SCD) is defined by subjective cognitive complaints (SCC) in the absence of objective cognitive impairment and has been associated with an increased risk of future cognitive decline. However, its impact on health-related quality of life (HRQoL) remains unclear. This is particularly relevant in early PD, when patients often maintain high levels of social-occupational functioning and subtle cognitive concerns may interfere with daily life. This study aimed to explore the association between SCC and HRQoL in cognitively unimpaired PD patients (PD-SCD). Methods: Cross-sectional data from the COPPADIS cohort were analyzed. Patients with normal cognition according to PD-MCI level I criteria (Parkinson's Disease-Cognitive Rating Scale > 81) were included. HRQoL was assessed using the 39-item Parkinson's Disease Questionnaire (PDQ-39). SCC were defined as a Non-Motor Symptoms Scale (NMSS) domain 5 ≥ 1. Results: A total of 497 patients with median age 62 years, disease duration 4 years, and 61% of PD-SCD were included. HRQoL was significantly worse in PD-SCD patients across all PDQ-39 domains. In adjusted linear regression models, PD-SCD was independently associated with higher PDQ-39 total score as well as with worse scores in activities of daily living, social support, cognition, and communication domains. Conclusions: PD-SCD is independently associated with poorer HRQoL across multiple domains. These findings highlight the clinical relevance of SCC within a patient-centered approach to PD management.