# Persistence and adherence to levodopa adjunct medications in elderly patients with Parkinson’s disease: a retrospective cohort study using a Japanese claims database

## TL;DR

This study examines how long elderly Japanese Parkinson's patients stay on levodopa adjunct medications and finds that adherence is high, though many discontinue treatment within a year.

## Contribution

The study provides new insights into medication persistence and adherence patterns for levodopa adjuncts in elderly Japanese PD patients using a claims database.

## Key findings

- The 1-year treatment persistence rate was 44.8% among elderly Parkinson’s patients.
- Zonisamide had the highest persistence rate at 59.5%.
- High adherence (≥80% days covered) was observed in 96.9% of patients.

## Abstract

We investigated treatment persistence and adherence for levodopa adjunct medications and their relationship with demographic factors in Japanese patients with Parkinson’s disease (PD).

This longitudinal retrospective study used a Japanese health insurance claims database for levodopa adjunct medications in patients newly prescribed anti-PD drugs other than levodopa between December 2020 and November 2021. Patients with a PD diagnosis were included in this study, and 17 anti-PD drug cohorts were formed. The primary outcomes were treatment persistence and adherence over 1 year. Multivariate analysis was conducted to evaluate demographic factors associated with treatment persistence/adherence.

In total, 7,605 patients were included in this analysis, with a mean age of 77.2 years, and 43.6% were male. The 1-year treatment persistence rate was 44.8%. Median persistent treatment duration over 1 year was 270.0 days. Persistence rates ranged from 28.6 to 59.5% across the drug cohorts, and were highest for zonisamide (59.5%) followed by safinamide (55.8%). The proportion of patients with proportion of days covered ≥80% (good treatment adherence) was 96.9% in the all-drugs cohort and ≥ 90% in each drug-specific cohort. In the multivariate analysis, the factor most strongly associated with non-persistence was the number of concomitant anti-PD drugs (risk ratio [RR] 0.85 per 1 unit increase), with the exception of inpatient prescriptions (RR 0.75).

More than half of the new anti-PD drugs added to levodopa were discontinued within 1 year, and adherence to treatment, as assessed by filling records, was extremely high in patients with PD, including the elderly population.