Non-motor symptom burden is strongly correlated to motor complications in patients with Parkinson's disease

Background and purpose: The objective of this study was to analyze the relationship between motor complications and non-motor symptom (NMS) burden in a population of patients with Parkinson's disease (PD) and also in a subgroup of patients with early PD.

Methods: Patients with PD from the COPPADIS cohort were included in this cross-sectional study. NMS burden was defined according to the Non-Motor Symptoms Scale (NMSS) total score. Unified Parkinson's Disease Rating Scale (UPDRS) part IV was used to establish motor complication types and their severity. Patients with ≤5 years of symptoms from onset were included as patients with early PD.

Results: Of 690 patients with PD (62.6 ± 8.9 years old, 60.1% males), 33.9% and 18.1% presented motor fluctuations and dyskinesia, respectively. The NMS total score was higher in patients with motor fluctuations (59.2 ± 43.1 vs. 38.3 ± 33.1; P < 0.0001) and dyskinesia (63.5 ± 40.7 vs. 41.4 ± 36.3; P < 0.0001). In a multiple linear regression model and after adjustment for age, sex, disease duration, Hoehn & Yahr stage, UPDRS-III score and levodopa equivalent daily dose, UPDRS-IV score was significantly related to a higher NMSS total score (β = 0.27; 95% confidence intervals, 2.81-5.61; P < 0.0001), as it was in a logistic regression model on dichotomous NMSS total score (≤40, mild or moderate vs. >40, severe or very severe) (odds ratio, 1.31; 95% confidence intervals, 1.17-1.47; P < 0.0001). In the subgroup of patients with early PD (n = 396; mean disease duration 2.7 ± 1.5 years), motor fluctuations were frequent (18.1%) and similar results were obtained.

Conclusions: Motor complications were frequent and were associated with a greater NMS burden in patients with PD even during the first 5 years of disease duration.