Motor Fluctuations Development Is Associated with Non-Motor Symptoms Burden Progression in Parkinson's Disease Patients: A 2-Year Follow-Up Study

The aim of the present study was to analyze the progression of non-motor symptoms (NMS) burden in Parkinson's disease (PD) patients regarding the development of motor fluctuations (MF). PD patients without MF at baseline, who were recruited from January 2016 to November 2017 (V0) and evaluated again at a 2-year follow-up (V2) from 35 centers of Spain from the COPPADIS cohort, were included in this analysis. MF development at V2 was defined as a score ≥ 1 in the item-39 of the UPDRS-Part IV, whereas NMS burden was defined according to the Non-motor Symptoms Scale (NMSS) total score. Three hundred and thirty PD patients (62.67 ± 8.7 years old; 58.8% males) were included. From V0 to V2, 27.6% of the patients developed MF. The mean NMSS total score at baseline was higher in those patients who developed MF after the 2-year follow-up (46.34 ± 36.48 vs. 34.3 ± 29.07; = 0.001). A greater increase in the NMSS total score from V0 to V2 was observed in patients who developed MF (+16.07 ± 37.37) compared to those who did not develop MF (+6.2 ± 25.8) ( = 0.021). Development of MF after a 2-year follow-up was associated with an increase in the NMSS total score (β = 0.128; = 0.046) after adjustment to age, gender, years from symptoms onset, levodopa equivalent daily dose (LEDD) and the NMSS total score at baseline, and the change in LEDD from V0 to V2. In PD patients, the development of MF is associated with a greater increase in the NMS burden after a 2-year follow-up.