Purpose: To determine whether systemic comorbidity is associated with reduced adherence to glaucoma medication and whether this decrease varies according to the number of comorbidity and the time after glaucoma onset.
Design: Cohort study.
Methods: Setting: Population-based.
Study population: All patients with confirmed newly diagnosed glaucoma in one or both eyes were identified using National Health Insurance (NHI) claims data from Taiwan.
Observation procedure: Individuals with newly diagnosed glaucoma were followed up for 5 years from onset. The study period was from January 1, 2011, to December, 31, 2020. Patient comorbidities were identified using the Deyo-Charlson Comorbidity Index. Adherence was measured using the medication possession ratio (MPR). The MPR was calculated by dividing the total number of days a patient had a supply of glaucoma medication by 365. Data for the MPR were extracted from NHI outpatient and drug records.
Results: This study included a total of 50 408 patients. Compared with patients without comorbidity, patients with at least 1 comorbidity exhibited higher MPR in the first 2 years following glaucoma onset. However, their MPR decreased in the long term, specifically in the fourth and fifth years after onset. Additionally, the degree of nonadherence increased with the number of comorbidities. Patients with ≥4 comorbidities had significantly lower glaucoma medication adherence, with reductions of 6.4% (P = .033) and 11.8% (P < .001) in the fourth and fifth years after glaucoma onset, respectively.
Conclusion: The presence of comorbidity can reduce glaucoma medication adherence by up to 12% in the long term. More comorbidities may increase the burden of managing chronic diseases; as a result, treatment for glaucoma may not receive priority due to the absence of clear symptoms of the condition.
Copyright © 2024. Published by Elsevier Inc.