Comparison of long-term use of prolonged-release ropinirole and immediate-release dopamine agonists in an observational study in patients with Parkinson's disease.

ABSTRACT

PURPOSE: To estimate the risk of dyskinesia and impulse control disorders (ICDs) in patients with Parkinson's disease (PD) prescribed ropinirole prolonged-release (R-PR) compared to those prescribed immediate-release dopamine agonists (IR-DA) as monotherapy. METHODS: PD patients initiating R-PR or IR-DA as monotherapy between 2008 and 2013 were identified on the Clinical Practice Research Datalink. The cohorts were propensity score matched on a 11 basis. The incidence of dyskinesia and ICD in each treatment cohort and the incidence rate ratios were calculated. Adherence to medication and time to levodopa initiation were also evaluated. RESULTS: We identified 341 patients in each treatment cohort after propensity score matching. The baseline characteristics were generally comparable. Dyskinesia incidence in R-PR and IR-DA cohorts was 2.98 (95% CI 0.74-11.9) and 3.93 (95% CI 0.98-15.7) per 1000 person-years, respectively (incidence rate ratio of R-PR vs ID-DA 0.76, 95% CI 0.11-5.38). Less than five cases of ICD were identified and all occurred in the IR-DA cohort. The patients in the R-PR cohort remained on treatment for a significantly longer duration than those in the IR-DA cohort (682 days vs 444 days; P < .0001) and had greater adherence to the medication. The median time to levodopa initiation was 417 days (IQR 205-736) in R-PR vs 297 days (IQR 111-552) in IR-DA cohort. CONCLUSIONS: The number of dyskinesia and ICD events was lower than expected, resulting in an underpowered study. A significantly longer persistence and greater adherence to medication was observed in patients receiving R-PR compared to IR-DA.