This was a retrospective, observational cohort study using a large health insurance claims database Subjects included patients with PD who were receiving LC without entacapone and then received either an add-on therapy with entacapone as a separate tablet (LC and E) or LCE as a single tablet (LCE) The primary study outcome was treatment adherenceTreatment adherence was estimated from pharmacy refills based on the percentage of days covered (PDC) with LCE or LC and E during follow-up and compared for patients receiving LCE and LC and E using multivariate regression analysesMultivariate analyses controlling for differences between groups in baseline characteristics, including pre-index dosage of and adherence with LC, receipt of LCE (n=388) was associated with a 26% lower risk of discontinuation (95% CI: 6–42%; p