Objectives: Although levodopa (LD) is the gold standard therapy for symptomatic treatment of Parkinson's disease (PD), the chronic use of LD leads to the development of motor complications in almost all patients.
Patients and methods: We assessed the presence and risk factors for motor complications in PD patients on LD therapy. We examined 555 PD patients on LD for the presence or absence of wearing-off (WO+/-) and dyskinesia (DK+/-).
Results: WO was present in 46.3%, and DK in 30.1% of patients. The mean age at onset of symptoms were earlier in WO(+)/DK(+) groups (p<0.001). The duration of PD was longer in WO(+)/DK(+) groups (p<0.001). The time between the first symptom and the occurrence of WO/DK, or LD initiation were not significantly different. The initial LD dose was significantly higher in WO(+) compared to WO(-) (300.1mg/d versus 232.5mg/d, p<0.001), and DK(+) compared to DK(-) groups (291.4 mg/d versus 251.9 mg/d, p=0.001). The time until dopamine agonist (DA) initiation was longer in WO(+)/DK(+) groups (p<0.001). WO (p<0.001) and DK (p=0.002) were more common in patients with H&Y stages 3+4. UPDRS scores were higher in WO(+) and DK(+) patients (p<0.001 and p=0.027).
Conclusion: Our study showed that the development of motor complications was associated with early onset PD, longer disease duration, advanced disease, higher initial LD dose, longer LD use, and late DA initiation, but not with the timing of LD initiation.