Persistence of topical glaucoma medication: a nationwide population-based cohort study in Taiwan.

Abstract

Medication persistence is an important factor for treatment effect in patients with glaucoma. Evaluating risk factors for refill discontinuation might be helpful for improving persistence and preventing blindness in patients with glaucoma. To estimate the persistence rate with topical glaucoma medication 2 years after diagnosis and evaluate risk factors for nonpersistence among patients in Taiwan with open-angle glaucoma and ocular hypertension. A retrospective population-based study using claims data from the National Health Insurance Research Database. One million patients were randomly selected from the registered beneficiaries of the National Health Insurance Research Database in 2000. All patients with newly diagnosed open-angle glaucoma and ocular hypertension were included and followed up until December 31, 2008. Patients were included in the analysis only if they had follow-up data for more than 2 years after diagnosis. Nonpersistence was defined as the patient not refilling any topical glaucoma medication for more than 90 days. Patient characteristics, prescription-related clinical factors, and physician and hospital characteristics were identified and considered in the analysis. The rate of persistence was estimated and risk factors for nonpersistence were investigated using Cox proportional regression models. A total of 3134 patients were identified and observed in the study. After a 2-year follow-up, 759 patients (24.2%) persisted with their glaucoma medications. Multivariate analysis showed that patients' living or working areas (P < .001), number of glaucoma medications (P < .001), prescription of pilocarpine hydrochloride (adjusted ratio of persistence = 0.72; 95% CI, 0.59-0.88) or prostaglandin analogs (adjusted ratio of persistence = 2.04; 95% CI, 1.82-2.33), the year in which glaucoma diagnosis was made (adjusted ratios of persistence for patients whose condition was diagnosed after 2004 = 1.18; 95% CI, 1.09-1.27), sex of the main physicians (adjusted ratios of persistence for male ophthalmologists = 0.82; 95% CI, 0.74-0.90), treatment in hospitals (P < .001), and continuity of care index (P < .001) were associated with patients' persistence with glaucoma medications. The rate of persistence for glaucoma medications is low in Taiwan, although health care costs, including the cost of medication, are mostly covered by the nationwide health insurance system. This study suggests that factors other than cost, such as physician-patient relationship and patient education, may play an important role in the persistence of topical glaucoma medication.