Health-related quality of life in early Parkinson's disease: the impact of nonmotor symptoms.

Nonmotor symptoms (NMS) are common in patients with established Parkinson's disease (PD) and have a major impact upon quality of life. We investigated the significance of NMS in relation to health-related quality of life (HRQoL) in patients with newly diagnosed PD. Patients and healthy controls were recruited as part of the Incidence of Cognitive Impairment in Cohorts with Longitudinal Evaluation in Parkinson's Disease Study. Prevalence of NMS was determined with the Non-Motor Symptom Questionnaire. HRQoL was recorded with the 39-item Parkinson's Disease Quality of Life Questionnaire (PDQ-39). Further assessments included measures of motor disability, depression, sleep, and cognition. One hundred and fifty-eight patients with newly diagnosed PD and 99 controls participated in this cross-sectional study. Patients reported greater numbers of NMS than controls (mean 8.3 ± 4.3 versus 2.8 ± 2.5 symptoms; P < 0.001). Patients reported lowest HRQoL in the domains assessing bodily discomfort, mobility, and activities of daily living. Motor and nonmotor symptoms impacted negatively upon HRQoL scores. Patients with the postural instability and gait difficulty motor subtype reported worse HRQoL, compared with those with tremor-dominant disease. Depression (P < 0.001), incomplete bowel emptying (P < 0.001), anxiety (P < 0.001), impaired concentration (P < 0.001), memory complaints (P < 0.001), and insomnia (P = 0.001) had the greatest negative impact upon HRQoL. NMS are common in patients with early PD and represent a significant cause of poorer health-related quality of life. Cognitive, neuropsychiatric, and sleep disturbances are particularly associated with reduced well-being. Screening and management of these symptoms should be prioritized at the time of diagnosis.