Measurement of persistence and adherence to regimens of IOP-lowering glaucoma medications using pharmacy claims data

Determine persistence and adherence of glaucoma patients to therapeutic regimens of prostaglandin/prostamide-class IOP-lowering medications.

Retrospective, population-based study.

Glaucoma patients in the IMS Health LifeLink database with a pharmacy claim for latanoprost (n = 1567), travoprost (n = 381), or bimatoprost (n = 476) between September, 2001 and March, 2002 who had no claims for IOP-lowering medication in the previous 180 days, and who were persistent during the first 90 days of therapy. Values reported in the quantity dispensed and days supply fields of the database were used in an algorithm that corrected anomalous data and adjusted days supply to calculate the main outcome measures, persistence, and adherence to therapy.

The percentage of patients persistent for the 12-month observation period was 69.4% (1087/1567) for those prescribed latanoprost, 70.6% (269/381) for those prescribed travoprost, and 68.1% (324/467) for those prescribed bimatoprost. Mean adherence for patients prescribed latanoprost was 75.4% of the year, for those prescribed travoprost, 77.1% of the year, and for those prescribed bimatoprost, 78.2% of the year. The mean number of days adherent for bimatoprost-treated patients (291.2 days) was significantly greater than for latanoprost-treated patients (281.0 days), and not remarkably different from travoprost-treated patients (287.0 days).

Overall, patients in this study who were taking IOP-lowering prostaglandin/prostamide medications had a mean adherence rate of 76% on average, suggesting that opportunities remain for improvement of adherence to therapeutic regimens for glaucoma treatment with prostamides and prostaglandins.