The value-based medicine comparative effectiveness and cost-effectiveness of penetrating keratoplasty for keratoconus.

OBJECTIVE

To perform a base case, comparative effectiveness, and cost-effectiveness (cost-utility) analysis of penetrating keratoplasty for patients with severe keratoconus.

METHODS

Visual acuity data were obtained from a large, retrospective multicenter study in which patients with keratoconus with less than 20/40 best corrected visual acuity and/or the inability to wear contact lenses underwent penetrating keratoplasty, with an average follow-up of 2.1 years. The results were combined with other retrospective studies investigating complication rates of penetrating keratoplasty. The data were then incorporated into a cost-utility model using patient preference-based, time trade-off utilities, computer-based decision analysis, and a net present value model to account for the time value of outcomes and money. The comparative effectiveness of the intervention is expressed in quality-of-life gain and QALYs (quality-adjusted life-years), and the cost-effectiveness results are expressed in the outcome of $/QALY (dollars spent per QALY).

RESULTS

Penetrating keratoplasty in 1 eye for patients with severe keratoconus results in a comparative effectiveness (value gain) of 16.5% improvement in quality of life every day over the 44-year life expectancy of the average patient with severe keratoconus. Discounting the total value gain of 5.36 QALYs at a 3% annual discount rate yields 3.05 QALYs gained. The incremental cost for penetrating keratoplasty, including all complications, is $5934 ($5913 discounted at 3% per year). Thus, the incremental cost-utility (discounted at 3% annually) for this intervention is $5913/3.05 QALYs = $1942/QALY. If both eyes undergo corneal transplant, the total discounted value gain is 30% and the overall cost-utility is $2003. Surgery on the second eye confers a total discounted value gain of 2.5 QALYs, yielding a quality-of-life gain of 11.6% and a discounted cost-utility of $2238/QALY.

CONCLUSIONS

Penetrating keratoplasty for patients with severe keratoconus seems to be a comparatively effective and cost-effective procedure when compared with other interventions across different medical specialties.