Dopamine agonist monotherapy utilization in patients with Parkinson's disease

To characterize patients with Parkinson's disease (PD) who initiated dopamine agonist (DA) monotherapy, describe medication utilization and provider types, and estimate medication adherence and discontinuation rates.

Retrospective study identified patients with PD in the Optum Research Database and included those with ≥1 claim for DA or levodopa between 09/01/2012 and 12/31/2018, ≥2 PD diagnoses, commercial or Medicare Advantage Part D (MAPD) insurance, ≥40 years old, and continuous medical and pharmacy coverage ≥12 months before and after index date. A subset of patients receiving DA monotherapy was selected for this analysis. Variables were analyzed descriptively. Adherence was measured with medication possession ratio (MPR) and proportion of days covered (PDC); defined as ≥0.80.

Patients (N = 642) had mean (SD) age of 70.2 (9.9) years, 70.6 % had MAPD coverage, and 61.7 % were male. Neurologists prescribed 64.6 % of DA monotherapy, and 56.9 % of patients had ≥2 PD diagnoses before or on the index date. Index therapy was discontinued by 44.1 % of patients, and 55.9 % persisted for 12 months without change. Mean (SD) time to discontinuation was 102 (79) days. Mean (SD) MPR for patients (n = 562) with ≥2 fills was 0.84 (0.2); 70.3 % were MPR adherent. Mean (SD) PDC for all 642 patients was 0.66 (0.3); 50.5 % were PDC adherent.

Adherence and continuation of therapy were suboptimal, which could translate into poor patient outcomes. Future studies could provide insights on the impact of low adherence and persistence with DA monotherapy.