Predictors of health-related quality of life in Parkinson's disease

Background: Health-related quality of life in Parkinson's disease may be affected by a wide range of motor and non-motor symptoms. Identifying which symptoms are significant predictors of health-related quality of life in Parkinson's disease prioritizes symptoms for treatment, therapeutic development, and clinical outcomes. Objectives: To determine predictors of health-related quality of life in patients with Parkinson's disease. Methods: We recruited 102 subjects into a prospective study to investigate neuropsychiatric symptoms in Parkinson's disease. Health-related quality of life was measured with the 39-item Parkinson's Disease Questionnaire. Subjects completed the Movement Disorder Society Unified Parkinson's Disease Rating Scale Parts I-IV as well as validated scales to assess anxiety, depression, apathy, cognition, psychosis, impulsive-compulsive disorder, autonomic dysfunction, sleep quality, excessive daytime sleepiness, and rapid eye movement sleep behavior disorder. We used univariate analyses to select clinical predictors to construct a multivariate regression model to determine which predictors were independently associated with worse health-related quality of life. Results: In a multivariate linear regression model adjusted for age and gender, higher scores for the International Parkinson and Movement Disorder Society Unified Parkinson's Disease Rating Scale part II as well more severe symptoms of depression, anxiety, apathy, and excessive daytime sleepiness were associated with worse health-related quality of life. The model explained 78% of the variance of health-related quality of life, and the non-motor symptoms explained 49% of the variance. Conclusions: Anxiety, depression, excessive daytime sleepiness, apathy, and impairment in activities of daily living related to motor symptoms were independently associated with worse health-related quality of life.