Glaucoma medication persistence with a fixed combination versus multiple bottles.

OBJECTIVE: To determine if prescribing combination therapy versus two or three separate bottles results in greater persistence among patients with glaucoma.
METHODS: Using a retail pharmacy claims database, three glaucoma patient cohorts were defined and followed for 12 months (January 2004 through December 2004). Patients in cohort 1 had a prescription for a single fixed-combination therapy during the month of January 2004. Cohort 2 consisted of patients with prescriptions for a beta-blocker and one other glaucoma product in the same month. Cohort 3 comprised patients with prescriptions filled for three different glaucoma therapies during the first month. A fixed-combination formulation may have been included in cohorts 2 and 3 as well, but was counted as a single bottle. Persistence rate, defined as the percentage of patients who did not discontinue their medication over the 12-month period, was calculated.
RESULTS: Cohort 1 (one bottle; n = 14 742) was more persistent than cohort 2 (two bottles; n = 18 411), with 35.3% vs. 27.2% of patients remaining on therapy at the end of the study period (p < 0.0001). Cohort 3 (n = 4826), with three separate bottles per patient, had the lowest percentage remaining on therapy (23.9%; p < 0.0001).
CONCLUSION: Analyses of pharmacy database data are limited by the possibilities of misidentifying newly treated patients or misclassifying added versus switched medications. As the number of separate products used for glaucoma therapy increases, patient persistence decreases. A management regimen requiring as few products as possible may enhance glaucoma patient persistence.