Background: Health-related quality of life (HRQoL) is an important outcome in patients with Parkinson's disease (PD). A broad list of motor and non-motor features affect quality of life, however, there is a dearth of information about the complexity of interrelationships between its determinants in different phenotypes.
Objective: We aimed to find independent determinates and the best structural model for HRQoL, and investigate the heterogeneity between PD patients with different phenotypes regarding onset-age, progression rate and dominant symptom.
Patients and methods: A broad spectrum of demographic, motor and non-motor characteristics were investigated in 157 idiopathic PD patients namely comorbidity profile, nutritional status, UPDRS, psychiatric symptoms, fatigue, psychosocial functioning and PD severity index using Parkinson's Disease Questionnaire-39. Structural equation model and multivariate regressions were applied.
Results: Female sex, anxiety, depression and UPDRS-part II scores were the significant independent determinants of PD severity index. A model consisted of global motor, non-motor and co-morbidity components was able to explain 89% of the variance in HRQoL. In older-onset and slow-progression phenotypes, motor domain showed smaller contribution and the majority of its effects was mediated through non-motor features. Comorbidity component was a significant determinant only among older-onset and non-tremor-dominant patients. Fatigue was not a significant indicator of non-motor component to affect quality of life in rapid-progression PD.
Conclusion: Our findings showed outstanding heterogeneities in the pattern and determinants of HRQoL in different PD phenotypes, which should be considered during the assessments and developing personalized interventions to improve life quality in PD patients with different prominent features.
© 2015 Published by Elsevier Inc.