Health-related quality of life in Parkinson’s disease: a cross-sectional study focusing on non-motor symptoms

BACKGROUND: The objective of this study was to investigate factors affecting health-related quality of life (HRQoL) among Estonian persons with Parkinson’s disease (PD). METHODS: 268 persons with PD were evaluated using: the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS); the Hoehn and Yahr scale (HY); the Schwab and England Activities of Daily Living scale (SE-ADL); the Beck Depression Inventory (BDI); the Mini Mental State Examination (MMSE); the Parkinson’s Disease Questionnaire (PDQ-39). Additional questions on clinical and socio-demographic variables were asked during a semi-structured interview. Predictors of HRQoL were tested using multiple regression analysis. RESULTS: The main predictors of low HRQoL were depression and motor and non-motor aspects of daily living. 59.9 % of the variation in the PDQ-39 summary index (SI) score was explained by the predictive variables identified in this study. None of the socio-demographic variables (age, gender, urban/rural living, marital status, living alone/with others, education level) were significant predictors of HRQoL. Prevalence of non-motor Parkinson’s symptoms were high (99.6 %); cognitive impairment, sleep and urinary problems were the most common. All non-motor symptoms correlated significantly with low HRQoL, except the features of impulse control disorders (ICDs). CONCLUSIONS: Depression and motor and non-motor daily living experiences were found to be significant and independent factors of low HRQoL in persons with PD. Depression was the strongest determinant of low HRQoL. Our results highlight the importance of recognition and management of non-motor symptoms, as these features had more impact on patients’ HRQoL than clinically assessed motor symptoms.