Sleep problems affect quality of life in Parkinson's disease along disease progression

Objectives: Non-motor symptoms (NMS) frequently impact health-related quality of life (HRQoL) in patients with Parkinson's Disease (PD). Sleep problems represent one of the main NMS complained by PD patients. In this observation study, sleep problems measured by Parkinson's Disease Sleep Scale - 2nd version (PDSS-2), and HRQoL measured by Parkinson's Disease Questionnaire-39 (PDQ39) were quantified in patients with PD ranging from mild to moderate-advanced disease stages, and correlated to motor impairment and anti-PD therapy. Methods: We included idiopathic PD patients who underwent PDSS-2 and PDQ39. Moreover, we assessed patients' motor symptoms by rating the Unified Parkinson's Disease Rating Scale (UPDRS) - III section (motor examination), patients' PD status following H&Y stage, and levodopa equivalent daily dose (LEDD). Results: One-hundred and fifty-four patients with PD were included and distributed for H&Y stage. PDSS-2 and PDQ39 total and sub-items scores significantly increased with the H&Y stage. PDSS-2 total score significantly correlated with PDQ39 total score (γ = 0.63, P < 0.01). Finally, distributing PD patients according to the PDSS-2 cut-off for detecting sleep disturbances, we found in poor sleepers (n = 58) higher PDQ39 scores than good sleepers (n = 89). Conclusions: Sleep problems are very common in patients with PD and severely impact on HRQoL. Sleep impairment and low HRQoL occur from the early stages of the disease and deteriorate along disease progression. Further studies investigating sleep and quality of life should be planned for targeting sleep improvement to increase HRQoL and possibly reduce motor impairment.