Pharmacotherapy compliance in patients with ocular hypertension or primary open-angle glaucoma

The aim of this study was to compare rates of pharmacotherapy coverage in patients with ocular hypertension (OH) and patients with primary open-angle glaucoma (POAG).

Retrospective cohort study analysis of a nationally representative, multimanaged health plan database (PharMetrics; 1998-2005) which included 4818 medicated OH patients and 52,985 medicated POAG patients with at least 1 year of continuous enrollment and at least one prescription for IOP-lowering medication during the first year of follow-up. Patients selected for the current study were nested within the cohort of OH patients (n = 36,767) and POAG patients (n =72,412) previously reported. Of the previously reported OH cohort, only 13.1% of patients filled at least one prescription, as compared to 73.2% of the previously reported POAG cohort. Medication coverage was defined as the percent of days during which a patient was in possession of IOP-lowering therapy over the first year of follow-up (medication coverage = number of covered days/365). Compliant patients were defined as those with >or= 75th percentile medication coverage.

POAG patients had slightly longer mean length of enrollment in the database (2.5 years, SD = 1.2) than did OH patients (2.4 years, SD = 1.1; P < 0.0001). The mean medication coverage was 50% for the POAG cohort (SD = 0.26) and 40% for the OH cohort (SD = 0.25; P < 0.0001). In multivariate models controlling for key covariates of interest, POAG patients were 1.9 (95% CI: 1.7 to 2.0) times more likely to be compliant with their pharmacotherapy than OH patients.

In general, pharmacotherapy coverage was poor. Patients with POAG, a more severe condition, were significantly more covered with pharmacotherapies than patients with OH. It is important to implement strategies to help improve patient coverage prior to occurrence of more severe disease.