Abstract
Purpose: :
To assess the association between gaps in adherence with glaucoma medications and clinical severity among glaucoma patients at San Francisco General Hospital.
Methods: :
In this case-control study of 126 patients with established glaucoma subject pharmacy records were obtained and analyzed. Medication adherence was calculated as the proportion of days covered (PDC) for filled prescriptions of topical prostaglandin analogues, beta-blockers, adrenergic agents, and carbonic anhydrase inhibitors. As reported in prior studies, cases (poor medication adherence) and controls (acceptable medical adherence) were classified based on a PDC < 0.80 and ≥ 0.80, respectively. Glaucoma severity was classified using the American Academy of Ophthalmology Preferred Practice Patterns guidelines.
Results: :
Mean PDC was 88% for severe glaucoma patients and 75% for mild/moderate glaucoma patients. In the unadjusted analysis, patients with mild/moderate glaucomatous disease were significantly less likely to have been adherent to their medications than patients with severe disease (crude OR 0.458, .223-.937, p = 0.048). In the multivariate regression analysis, mild/moderate glaucomatous disease remained significantly associated with reduced adherence relative to advanced disease (adjusted OR 0.683, 95% CI 0.475-0.984, p = 0.041).
Conclusions: :
Patients with advanced disease were more likely to be adherent with prescribed medical therapy relative to those with less severe disease in this study population. While this cross sectional design cannot establish causality, it is unlikely that poor compliance with medical therapy improves outcome and thus the more tenable conclusion from our findings is that increased disease severity resulted in better compliance with therapy, a result which is not surprising given that early to moderate glaucomatous disease is often asymptomatic.
Keywords: clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • clinical (human) or epidemiologic studies: risk factor assessment • clinical (human) or epidemiologic studies: outcomes/complications