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PD-SCD and health-related quality of life: Findings from COPPADIS study

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Created On: 30/10/2026

Cognitive complaints can emerge in Parkinson’s disease (PD) before objective cognitive impairment becomes apparent.

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Key take away

Subjective cognitive decline is independently linked with poorer health-related quality of life in cognitively unimpaired patients with Parkinson’s disease, particularly across daily functioning, social support, cognition, and communication.

Background

Cognitive complaints can emerge in Parkinson’s disease (PD) before objective cognitive impairment becomes apparent. Parkinson’s disease-associated subjective cognitive decline (PD-SCD), marked by perceived cognitive difficulties despite preserved objective cognitive function, has also been linked to a heightened risk of future cognitive deterioration. However, its broader influence on health-related quality of life (HRQoL) remains vague.

This investigation aimed to determine the explicit association between subjective cognitive complaints (SCC) and HRQoL among cognitively unimpaired patients with PD.

Method

Researchers conducted a cross-sectional analysis of the Collaborative Parkinson’s Disease Study (COPPADIS) cohort. The analysis included patients with normal cognition according to Level I criteria for Parkinson’s Disease-Mild Cognitive Impairment (PD-MCI), defined by a Parkinson’s Disease-Cognitive Rating Scale (PD-CRS) score greater than 81.

HRQoL was evaluated via the 39-item Parkinson’s Disease Questionnaire (PDQ-39). SCC were identified by a score of ≥1 in Domain 5 of Non-Motor Symptoms Scale (NMSS). Adjusted linear regression analyses assessed the independent association between PD-SCD and overall as well as domain-specific HRQoL.

Result

The study included 497 patients with PD (median age of 62 years, median disease duration of 4 years). SCD was identified in 61% of subjects. Patients reporting SCC exhibited significantly poorer HRQoL across all PDQ-39 domains. In adjusted linear regression analyses, PD-SCD remained independently linked with a higher total PDQ-39 score, reflecting poorer overall HRQoL, and worse scores in four specific domains:

Activities of daily living: Greater impairment in everyday functioning.
Social support: Less favorable outcomes in the social support domain.
Cognition: Greater perceived cognitive difficulties.
Communication: More substantial communication-linked difficulties.

The findings highlight a prominent link between SCC and a multidimensional quality-of-life burden, even in those without objectively measurable cognitive impairment.

Conclusion

PD-SCD is independently linked to diminished HRQoL across a broad spectrum of domains, emphasizing the clinical importance of recognizing subjective cognitive complaints within a comprehensive, patient-centered framework for PD management.