Efficacy and Safety of Entacapone Combined With Madopar in the Treatment of Early Parkinson's Disease: An Observational, Multicenter, Case-Control Study

Inclusion Criteria: Age between 18 and 80 years; Diagnosed with Parkinson's Disease based on the MDS criteria, confirmed by a movement disorder neurologist; Modified Hoehn and Yahr stage between 1 and 2.5; No prior use of entacapone; MMSE score ≥ 26; BDI (Beck Depression Inventory) score \< 15; Either: Has never used levodopa before, or Has been on a stable dose of levodopa (300-600 mg/day) for at least 1 month prior to enrollment; Stable doses of amantadine, anticholinergics, dopamine agonists, selegiline, or rasagiline are allowed if maintained for at least 30 days prior to and during the study; Willing and able to give informed consent and comply with study procedures, with caregiver support if needed. Exclusion Criteria: Previous use of entacapone or tolcapone for more than 30 days, or within 4 weeks before baseline; Use of dopamine agonists within 4 weeks before baseline; BDI score ≥ 15; MMSE score \< 26; Unstable levodopa dosage; History of dyskinesia; Diagnosis of atypical or secondary parkinsonism, or history of PD-related neurosurgery; Clinically significant medical conditions within the past 5 years that could interfere with study participation; Use of medications known to induce parkinsonism; Participation in other investigational drug trials within 30 days before baseline.