Adherence to antiparkinson medication in a multicenter European study

Two small studies reported suboptimal therapy adherence in Parkinson's disease. We conducted a larger multicenter European study to assess medicine‐taking behavior. Parkinson's disease patients taking dopaminergic therapy were enrolled in 8 centers in 5 countries, and disease severity and demographics recorded. Antiparkinson drug adherence was measured for 4 weeks using electronic monitoring bottles which record the date and time of cap opening (Aardex®, Switzerland). One hundred twelve patients, mean age 65 years (standard deviation (SD) 10), with Parkinson's disease for 7.7 (SD 8.2) years completed the study. Total median adherence (doses taken/doses prescribed) was 97.7% (interquartile range [IQ] 90.6–100), days adherence (correct dose days) was 86.2% (IQ 61.1–96.2) and timing adherence (doses taken at correct time intervals) was 24.4% (IQ 5.3–56.5). Fourteen patients (12.5%) took less than 80% of prescribed doses, which was defined as suboptimal adherence. Patients with satisfactory adherence took a median of 8 mg/day (IQ 0–33) less than their prescribed dose of levodopa (P = NS), while suboptimal adherence patients took a median of 481 mg/day (IQ 205–670) less than their prescribed dose (P = 0.0006). The Parkinson motor score was significantly higher in patients with suboptimal adherence at 29 (IQ 20–40), versus those with satisfactory adherence at 19 (IQ 13–26), P = 0.005. Once daily drugs had significantly better adherence when compared with drugs prescribed more frequently (P < 0.0001). Suboptimal therapy adherence is associated with significant deviation from prescribed levodopa doses, despite greater Parkinson's motor severity. Optimizing oral medication intake has a potential role in maximizing the therapy response in Parkinson's disease