Distribution of Adherence to Intraocular Pressure Lowering Agents among Glaucoma Patients Is Bimodal and Robust to Operational Definitions of Glaucoma and Adherence

Kaiser Permanente Southern California • 3.5 million members representative of California pop. • 6,000 physicians with 130 ophthalmologists Eligibility—Periods of medical and prescription coverage tracked Diagnosis and utilization • ICD-9 diagnoses, including provider and specialty • Administrative tracking of all procedures and encounters Pharmacy (electronic tracking since 1992) • 93% of members have prescription drug benefit • 97% of medications filled in Kaiser Permanente pharmacies • Low mean (<$11) and median (<$6) copays per 30-day fill Clinical Progress Notes (EMR available from 2005 for validation)