Refill Rates and Budget Impact of Glaucoma Lipid Therapy

Abstract

Drugs in the lipid class of glaucoma medications, including bimatoprost, travoprost and latanoprost, are effective at lowering intraocular pressure. In addition to clinical efficacy, the budget impact of long-term therapy with each medication is important for patients, physicians and managed-care decision makers to differentiate between the products and make informed decisions regarding the choice of therapy. This study aimed to determine the average number of days between refills for latanoprost, travoprost and bimatoprost, and to estimate the potential effect of differences in refill rates on pharmacy budgets. In this retrospective database analysis of pharmacy records, the dispensing patterns of patients with glaucoma lipid therapies were obtained. Patients with a pharmacy prescription for the 2.5 mL bottle of latanoprost, travoprost or bimatoprost between September 2002 and December 2002, and receiving continuous treatment defined as having at least one prescription for the same lipid agent and bottle size 1 year later between September 2003 and December 2003, were included in this study. The main outcome measures were mean number of days between refills, mean number of refills, cost per patient per year (based on the average wholesale price [AWP]), and annual refill cost differences between cohorts. The mean number of days between refills was 46.74 days, 53.65 days and 51.98 days for latanoprost, travoprost and bimatoprost, respectively (p < 0.0001, ANOVA). The mean number of refills per year was 7.1, 6.2 and 6.4 for latanoprost, travoprost and bimatoprost, respectively. Based on this and the AWP, the average cost per patient per year was $US435.16 for latanoprost, $US385.58 for travoprost and $US397.44 for bimatoprost. The cost savings per year if the population of patients using latanoprost (n = 79,820) used bimatoprost or travoprost instead would be approximately $US3.0-$US3.9 million. A statistically significant difference in mean days between refills was found among the three studied drugs. Latanoprost presented the highest annual cost followed by bimatoprost and travoprost.