Managing Glaucoma in those with Co-morbidity: Not as Easy as it Seems

Purpose: To identify the extent of use of medicines recommended to be used with caution in glaucoma patients with specified comorbidities and to determine evidence of associated harm. Methods: Retrospective cohort analysis from administrative claims data and prescription/event sequence symmetry analysis. Participants: Australian Government Department of Veterans' Affairs treatment card holders dispensed glaucoma eye-drops. Main outcome measures: Proportion of veterans with glaucoma and diabetes, airways disease, heart failure, ischemic heart disease or depression, dispensed glaucoma eye drops which should be used with caution. For harms, outcome measures were hospitalizations for airways disease and heart disease. Results: The cohort analysis included 25,984 veterans. Of these, 88% with airways disease were dispensed glaucoma eye drops with the potential to aggravate airways disease, 43% with heart failure were dispensed topical beta-blockers and 49% with depression received glaucoma eye drops which should be used cautiously in those with depression. We found increased risk of initiation of inhaled beta-agonist following timolol ( adjusted sequence ratio (ASR) 1.48, 99% CI 1.22-1.78) and latanoprost (ASR 1.24, 99% CI 1.11-1.38) initiation. We found increased risk of inhaled corticosteroid initiation following initiation of timolol (ASR 1.43, 99% CI 1.13-1.81). There was increased risk of antidepressant initiation following timolol initiation (ASR 1.24, 99% CI 1.07-1.43), and latanoprost (ASR 1.16, 99% CI 1.03-1.31). There was also increased risk of hospitalization for bradycardia following timolol initiation (ASR 2.22,99% CI 1.15-4.31). Conclusion: Use of glaucoma eye drops recommended to be used with caution in co-morbidities is common and was associated with adverse outcomes. Awareness of co-morbidities is required in the selection and prescription of glaucoma eye drops.