Drug Utilization, Adherence and Predictors of Drug-Changes and Discontinuation of Glaucoma Drug Therapies.

Abstract

Introduction: The present study aimed to analyze drug utilization, adherence, and predictors of therapy changes and discontinuation among incident patients with glaucoma in the Lombardy Region of Italy.

Methods: A cohort of 10,515 incident patients with glaucoma aged 50 years or older was identified from the Lombardy Region database. Patients were included if they received at least three consecutive prescriptions of antiglaucoma medications in 2010, with follow-up until December 31, 2018. Outcomes included drug utilization patterns, adherence (defined as covering ≥ 80% of follow-up days with medication), and predictors of therapy changes or discontinuation. Survival analysis and Cox regression models were used to assess time to therapy modification or discontinuation, adjusted for age, sex, chronic polypharmacy, and initial drug class.

Results: The mean age of the cohort was 70.2 years, with 54.8% women. Beta-blocking agents (37.8%), timolol combinations (26.2%), and prostaglandin analogues (25.2%) were the most prescribed initial therapies. Only 41.0% of patients were adherent to therapy. Over the follow-up period, 73.4% of patients modified or discontinued their initial therapy, with a median time to the first change of 666 days. Older age (hazard ratio, HR = 1.16, 95% confidence interval, CI 1.09-1.25) and chronic polypharmacy (HR = 1.12, 95% CI 1.07-1.17) were significant predictors of therapy modification. Discontinuation occurred in 64.2% of patients, with a median time of 1156 days. Older age (HR = 1.25, 95% CI 1.16-1.34) and chronic polypharmacy (HR = 1.21, 95% CI 1.15-1.27) were also predictors of discontinuation. Prostaglandin analogues and beta-blocking agents were associated with lower risks of therapy modification and discontinuation compared to other drug classes.

Conclusion: Older age and chronic polypharmacy were key predictors of therapy changes and discontinuation. Prostaglandin analogues and beta-blocker agents demonstrated greater therapy stability. These findings emphasize further need for targeted interventions to improve adherence and persistence, particularly among older patients and those with complex medication regimens.