Abstract
Purpose: :
To investigate patient persistence with topical prostaglandin analog medications.
Methods: :
Using medical and pharmacy claims data from a large US health insurer, we selected patients with first–time insurance claims for open angle glaucoma or ocular hypertension who initiated therapy with latanoprost, bimatoprost, or travoprost between April 2001 and June 2004. Patients were included only if they received the standard 2.5 ml bottles during their first continuous course of therapy. We examined the time to discontinuation of the initially prescribed medication. The supply time of each bottle was defined as 60 days. Adjusted relative risks were obtained using Cox proportional hazards models incorporating baseline characteristics that were associated with persistence. We also compared the mean number of dispensings of the initial medication in the first year and the proportion with a refill in hand at one year after the start of treatment. An additional analysis looked at patterns of first drug switching within the first year.
Results: :
We identified 2577 patients who initiated latanoprost, 341 who initiated bimatoprost, and 705 who initiated travoprost. Most patients appear to have discontinued the initial therapy during the first year; the mean duration of therapy prior to a discontinuation was 153 days for latanoprost, 106 days for bimatoprost, and 108 days for travoprost (p < 0.0001). The Cox model of time to discontinuation showed a 33% greater risk of discontinuation for bimatoprost initiators and a 31% greater risk for travoprost users compared to latanoprost initiators (p < 0.0001). Latanoprost initiators received a mean of 5.2 dispensings of the initial drug during the first year, compared to 4.3 for bimatoprost and 4.0 for travoprost ( p < 0.0001). Nearly half (47.9%) of latanoprost users had a refill in hand at 12 months, compared to 42.2% of bimatoprost users and 39.3% of travoprost initiators (p = 0.02 and p < 0.0001, respectively). Approximately 7% of each drug initiator group switched without a break to another glaucoma medication during the first year.
Conclusions: :
Continuous use of any topical prostaglandin without a break in therapy was uncommon. Many patients continued receiving refills, but with gaps during the first year after the start of treatment. Latanoprost was associated with greater persistence, a larger number of refills and a higher prevalence of refills in hand at the end of the first year of treatment than either bimatoprost or travoprost.
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • intraocular pressure