Persistency with latanoprost or timolol in primary open-angle glaucoma suspects.

PURPOSE: To evaluate persistency of pharmacotherapy in primary open-angle glaucoma suspects (glaucoma suspects) treated with latanoprost and timolol.
DESIGN: Retrospective, cohort study using the Protocare Sciences managed care database; approximately 3 million members in commercial health maintenance organizations and preferred provider organizations and in Medicare risk plans.
METHODS: Patients 20 years of age or older beginning therapy between January 1, 1997, and June 30, 2002, with latanoprost or timolol monotherapy were included. Patients must have been continuously enrolled and not undergone glaucoma surgery in the year preceding the index prescription fill and had glaucoma suspect diagnoses before and after the index date. Prescription refill records for all ocular hypotensives were extracted through June 30, 2002. The two outcome measures were (1) discontinuation of index drug, and (2) either discontinuation or change in index drug. Changing therapy was defined as switching to or adding another ocular hypotensive. Rates of discontinuation and discontinuation/change were compared using Cox regression models.
RESULTS: In all, 1,474 patients met the inclusion criteria. Latanoprost was prescribed for 583 patients (40%) and timolol for 891 (60%). Compared with latanoprost, those treated with timolol were 39% more likely to discontinue and 27% more likely to discontinue/change therapy (P <.001 for both comparisons). At 12 months, 39% of patients receiving latanoprost and 25% of those treated with timolol had not discontinued therapy; no discontinuation or change in therapy was seen in 30% and 18%, respectively.
CONCLUSIONS: Latanoprost-treated glaucoma suspects demonstrated significantly greater persistency than did patients treated with timolol. The reasons for this difference and its impact on intraocular pressure control and disease progression require further research.