Abstract
Purpose :
Corneal collagen cross-linking (CXL) is the first available treatment to reduce progression of keratoconus by strengthening corneal tissue using ultraviolet-A light and riboflavin. Traditionally, patients with keratoconus are managed with spectacles/contact lenses. Up to 20% go on to require corneal transplant. We conducted an economic evaluation of our hypothesis that CXL may be a cost-effective alternative to managing patients with spectacles/contact lenses, some of whom go on to require penetrating keratoplasty (PKP).
Methods :
We designed two microsimulation models to capture the natural history of keratoconus progression and the impact of CXL versus PKP. Health states included: 1. Keratoconus managed with spectacles/contact lenses, 2. Surgical intervention (CXL/PKP), 3. Post-operative success, 4. Post-operative vision loss/minor complication, 5. Post-operative irreversible vision loss/major complication, 6. Death. We simulated 10,000 individuals moving through health states in monthly cycles from time of diagnosis to death. We assigned conservative values for transition probabilities, costs, and health utilities (quality-adjusted life years, QALYs) using data from published sources. Costs and utilities were discounted at 5% per year. We calculated an incremental cost-effectiveness ratio (ICER) to compare the difference in costs to the difference in QALYs gained from CXL versus PKP.
Results :
Age of disease onset and death were set at 25 and 110 years, respectively. Using conservative model parameters, PKP lifetime costs and utilities were estimated to be $2297 USD ($792 USD discounted) and 47.42 QALYs (15.65 QALYs discounted). Costs and utilities associated with CXL were $1376 USD ($1257 USD discounted) and 48.09 QALYs (15.73 QALYs discounted). The discounted ICER comparing CXL to PKP was $5719 USD per QALY.
Conclusions :
Corneal collagen cross-linking is cost-effective compared to conventional management with possible PKP. We report a favourable ICER of $5719 USD per QALY. This is a conservative estimate, well within the cost-effectiveness threshold value of $30 000 USD per QALY suggested by the National Institute for Health and Care Excellence. Higher costs are offset by gains in health-related quality of life from early CXL. Additional cost-effectiveness studies comparing CXL to other treatment modalities may further elucidate the role for CXL in managing keratoconus today.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.