Hyperemia-associated costs of medication changes in glaucoma patients treated initially with prostaglandin analogs

Aims: To develop a model to estimate and compare the cost of changing therapy due to hyperemia in glaucoma patients treated initially either with latanoprost, bimatoprost, or travoprost monotherapy. Methods: Data collected from the HealthCore Integrated Research Database, as part of the Glaucoma Adherence and Persistency Study (GAPS), were used to populate the model. Patients with a documented diagnosis of glaucoma who were newly treated (no ocular hypotensive medication and no glaucoma-related procedure during 6 months before first prescription) with latanoprost, bimatoprost, or travoprost monotherapy were identified. The time horizon for the base-case model was the duration of chart abstraction (mean = 4.1 years); a 3-month model also was developed. Physician-reported rates of hyperemia were obtained from chart reviews of 300 patients. Transition rates reflected events related to reports of hyperemia where a physician-driven change (switch or discontinuation) in therapy was documented. The per-patient direct cost (2008) due to hyperemia-driven change in therapy was calculated as the sum of the cost of the initial prescription plus the cost of the office visit where the patient was evaluated and the decision to change therapy was made. Costs were stratified by whether patients were hyperemia free or discontinued the initial therapy due to hyperemia. Results: From the sample of 13,977 newly treated patients, 8,743 patients were started on a prostaglandin monotherapy only. Of these, 5,726 received latanoprost, 1,633 were treated with bimatoprost, and 1,384 received travoprost index monotherapy. Across all treatment groups, costs among hyperemia-free patients were US$73.67 versus US$140.02 for those who discontinued the initial prostaglandin due to hyperemia. Per-patient costs were lowest in the group treated initially with latanoprost. For the base-case model, with latanoprost as the reference, total per-patient incremental costs due to hyperemia-driven change in therapy were US$5.92 for bimatoprost and US$5.43 for travoprost. Results were not highly sensitive to increases either in the incidence of hyperemia among latanoprost-treated patients or in the cost of latanoprost. Conclusions: Hyperemia results in increased overall costs in patients treated with latanoprost, bimatoprost, and travoprost. Treatment with latanoprost is associated with lower hyperemia-related costs than treatment with bimatoprost or travoprost.