Travoprost versus latanoprost combinations in glaucoma: economic evaluation based on visual field deficit progression

Abstract

Objective: Changes in intraocular pressure (IOP) are known to be related to visual field deficit progression, although multiple models of this relationship exist. In addition, visual functioning is known to affect medical costs. The objective of this study was to project visual field deficit progression and subsequent costs based on clinical trial data.

Research design and methods: Using data from a randomized, 12-month, double-masked study, we compared the use of a fixed combination of travoprost 0.004%/timolol 0.5% (T/T) versus a fixed combination of latanoprost 0.005%/timolol 0.5% (L/T) on visual field deficit progression and associated costs. We applied published algorithms linking IOP to visual field changes to calculate the likelihood of visual field deterioration by treatment group. Differences in medical care costs were estimated using guideline-recommended practice patterns, Medicare hospital costs, and published estimates of differences in hospitalization by visual functioning.

Main outcome measures: Increase in visual field deficit progression rates, increase in annual hospital days per subject, and increase in annual hospital, outpatient, and total costs per subject.

Results: Predicted visual field deficit progression for T/T patients was less than that for L/T patients (not statistically significant). Projected annual medical care costs were 43 dollars lower for T/T vs. L/T patients.

Conclusions: By applying published algorithms linking IOP to visual field changes, this study projected long-term visual field deficit and associated costs. Use of a fixed travoprost/timolol solution may lead to less long-term visual field deficit progression and lower annual medical care costs than a fixed latanoprost/timolol solution.

Discussion: The use of clinical trial data may limit the applicability of these findings. However, this analysis of direct medical costs only is likely a conservative estimate of the costs associated with visual field deficits.