APR 15, 2009
The cost-utility model used in this study found penetrating keratoplasty to be very cost-effective for severe keratoconus patients compared with other interventions. Penetrating keratoplasty in one eye of a severe keratoconus patient resulted in a 16.5 percent quality of life improvement every day over the patient's 44-year average life expectancy, according to the authors' calculations. This compared favorably with the 20.7 percent quality-of-life improvement reported for first-eye cataract surgery and 12.7 percent gain for fellow eye cataract surgery.
Data on patients referred for keratoconus between 1984 and 1988 were incorporated into this study's base case cost-utility analysis. Penetrating keratoplasty was performed on 140 eyes of 123 patients. Their average age was 35, and they had BCVA of less than 20/40 or were not able to wear a contact lens in the affected eye. Mean BCVA improved from 20/70 preoperatively to 20/25 after a mean postsurgical follow-up of 2.1 years. Visual acuity was assumed to correspond with utility calculations. The graft failure rate used in the analysis was 2.1 percent, with repeat keratoplasty assumed. The graft rejection rate was 5 percent.
Average Medicare fee schedule costs corresponding to 2006 Current Procedural Terminology codes were used and facility fees based on 2006 Centers for Medicare and Medicaid Services ambulatory surgical center rates. Costs that did not occur within the first year were discounted at a three percent annual rate.
Severe keratoconus patients who underwent penetrating keratoplasty in one eye gained 5.36 quality-adjusted life-years (QALYs) or 3.05 QALYs at the discounted rate, according to the cost-utility model's results. The incremental cost-utility of the procedure was $1942 per discounted QALY, which is equal to quality-of-life improvement multiplied by the benefit's duration. Surgery on the second eye yielded an 11.6 percent quality-of-life gain, discounted improvement of 2.5 QALYs and discounted cost-utility of $2238/QALY. Quality-of-life improvement for bilateral penetrating keratoplasty was 30 percent, with a discounted QALY gain of 5.55.