Glaucoma medications and mortality: A retrospective cohort study

Purpose: This study presents a retrospective, cohort analysis to estimate the 4-year rate of all-cause risk-adjusted mortality for veterans who were dispensed glaucoma medications. The main outcome measures was hazard of death according to glaucoma medication exposure. Methods: Beneficiaries 40 years and older enrolled in Veterans Health Administration (VHA) with International Disease Classification diagnoses of glaucoma. VHA clinical and pharmacy data sets were linked with a national VHA mortality registry. Patients were identified with a primary diagnosis of glaucoma were then put into one of two groups, glaucoma medication exposure or nonexposure medication group. Four-year survival analysis using the Cox proportional hazard method was adjusted for comorbidities using pertinent demographic characteristics and hierarchical condition categories from the Centers for Medicare and Medicaid Services. Results: Of 214,971 beneficiaries with glaucoma or suspected glaucoma, 25,148 (11.7%) died during the study period. Compared to unexposed patients with glaucoma, the use of any class of glaucoma medication was associated with a statistically significant 7% reduced hazard of death (adjusted hazard ratio, 0.93; 95% confidence interval: 0.90-0.95). Reduced risk of death was found for multiple topical medication use, but not individual glaucoma agents. Conclusions: The seemingly inexplicable protective effect of glaucoma agents on all-cause mortality may best be explained by unmeasured confounding variables involved in the clinical decision of whether or not to treat patients with limited life expectancy for glaucoma.