Persistence with Prostaglandin Agonist Use with and without Adjunctive Therapy for Glaucoma Patients: A Canadian Population-Based Analysis

Background: Glaucoma is one of the leading causes of blindness and visual disability. Few studies have examined persistence and adherence with topical medications in glaucoma patients. Objective: The objective of this study was to compare patient persistence with prostaglandin agonist (PA) monotherapy versus with concomitant adjunctive therapy (AT) in Canada. Methods: Data were obtained from the Québec prescription claims database. Persistence rates were determined for previously treated naive glaucoma patients at 1 year after their index date for use of any of the three available PAs (bimatoprost, latanoprost, and travoprost). Patients who had at least 334 days on their index PA were defined as being persistent during the analysis timeframe. Patient baseline demographics and persistence rates were reported. A logistic regression was used for comparing the PA and PA + AT groups, which incorporated baseline cofounders, such as age and sex, in the analyses. Results: From an initial cohort of 28 534 patients, 14 893 were identified as naive to glaucoma therapy and had a PA as their index therapy. Of these, 11 197 (75.2%) continued to receive monotherapy and 3696 (24.8%) had an AT added to the PA; 59.0% were females, and the average age was 70.5 ± 11.3 years. Overall, at the end of the first year of therapy, 57.4% of patients were persistent on their index PA; however, a statistically significant difference was observed between the two subgroups, with 54.6% for those receiving PA monotherapy and 65.8% for those receiving PA + AT (p < 0.01) persistent with therapy. On average, 10.5 prescriptions per year were dispensed to persistent patients. Conclusions: In this Canadian population, persistence rates fall to approximately 60% at the end of the first year of therapy, with patients taking AT being more persistent. Similar persistence analyses are warranted on other populations, and would yield helpful data for conducting economic evaluations of non-persistence.