Abstract
Purpose: :
Studies report conflicting results as to whether intravitreal anti-VEGF therapy and PDT are cost-effective treatments for age-related macular degeneration (AMD). The majority of models assume patients to have only 1 eye. However, while one eye of patients may be treated, visual acuity in both eyes is important in determining quality of life and cost of visual impairment. Moreover, the second eye may develop AMD and cause loss in quality of life at a later stage. Only two studies are available which study AMD progression in 2 eyes, of which neither includes the cost of visual impairment. We have developed a model addressing these issues and present its preliminary results, comparing anti-VEGFs, PDT, and no treatment.
Methods: :
We defined a 2-eye, patient-level, discrete event simulation model incorporating effectiveness data from major trials in AMD. The natural progression rate in terms of visual acuity and the risk of AMD in the second eye were based on meta-analysis. Quality of life was measured in AMD patients using the Health Utilities Index Mark 3 (HUI-3) questionnaire and associated with visual acuity in the better eye for quality-adjusted life-year (QALY) calculation. Costs were based on standard Dutch cost prices, volumes of direct and indirect resource utilisation on trial data and interviews with AMD patients, respectively. Base-case and probabilistic sensitivity analyses were performed. Univariate sensitivity analysis included changing the proportion of patients with 2 eyes affected at baseline, and changing the method of extrapolation of visual acuity for the period after treatment was stopped from last-observation-carried-forward to a gradual loss of visual acuity due to natural progression.
Results: :
Over 5 years, with 2 years of treatment, the base-case incremental cost-effectiveness ratio versus no treatment (ICER, cost per QALY), was €27,357 (US$36,658) for bevacizumab as needed (pro re nata, PRN), €55,000 (US$73,700) for pegaptanib, €115,812 (US$155,188) for ranibizumab PRN, and €156,545 (US$209,770) for PDT. Bevacizumab is equally as effective as ranibizumab, but is associated with less total costs. ICERs decreased with longer time horizon. Univariate sensitivity analysis did not significantly alter the ICERs.
Conclusions: :
In this more valid 2-eye model, including costs of visual impairment, using outcomes from recent AMD trials, bevacizumab appears to be the only cost-effective treatment for AMD.
Keywords: age-related macular degeneration