Cost-offset analysis: bimatoprost versus other prostaglandin analogues in open-angle glaucoma.

Objectives: To develop a cost-offset model from a US payer perspective comparing glaucomatous progression and costs among primary open-angle glaucoma (POAG) patients using bimatoprost, latanoprost, or travoprost.

Study Design: Cost-offset model.

Methods: A Markov cohort model was used to estimate glaucomatous progression for POAG patients over 7 years. The model assumed bimatoprost-treated patients had lower resulting intraocular pressure (IOP) (by 1 mm Hg) for all presenting IOP categories than latanoprost- or travoprost-treated patients. Patients with lower IOP were assumed to have lower probability of progression. Those that progressed were assumed to do so at a rate of -0.6 dB per year. Direct costs associated with mean deviation score categories were applied to each treatment cohort to calculate the expected 7-year costs of treating patients with each prostaglandin analogue (PGA). Literature was used to support assumptions. A budget impact analysis was conducted where all travoprost patients switched to generic latanoprost and where all bimatoprost patients switched to generic latanoprost. The base case market share was 22% bimatoprost, 23% travoprost, and 55% latanoprost.

Results: Model results demonstrate that for a managed care plan with 9500 PGA-treated glaucoma patients, exclusive bimatoprost use would prevent progression in 136 additional individuals compared with exclusive travoprost or latanoprost treatment. Model results demonstrate that greater IOP reduction from bimatoprost is associated with increased cost savings compared with latanoprost or travoprost treatments.

Conclusions: Model results demonstrate that greater IOP reduction from bimatoprost could reduce managed care spending.