Abstract
Purpose: :
Prior studies have shown that fellow eyes of patients with unilateral exudative age-related macular degeneration (AMD) are at high risk of converting to exudative AMD. The purpose of this study is to determine the incremental cost-effectiveness of using routine optical coherence tomography (OCT) screening of the fellow eyes of these patients with prompt initiation of treatment if asymptomatic exudation is detected.
Methods: :
Published data on second eye conversion rates, time tradeoff utilities and a threshold of <$50,000 per quality-adjusted-life-year gained are used to determine incremental cost-effectiveness. The usual care group is given anti-VEGF therapy when they are symptomatic and the behavior of visual acuity over time before treatment is modeled by [1/letter lost = 0.1448/ months of disease + 0.0133; Ophthalmology.2009;116:1901-7]. We assume that the experimental group undergoes monthly OCT screening of the fellow eye. 3 separate analyses are done: every-6-week bevacizumab, monthly ranibizumab or quarterly ranibizumab is given once intra/sub-retinal fluid is detected. Only direct costs using Medicare reimbursement rates are included.
Results: :
The cost effectiveness of screening increases as the cumulative conversion rate from nonexudative to exudative AMD in the fellow eyes increases. The minimum cumulative conversion rate required for cost-effectiveness decreases as the year by which the program needs to be cost-effective increases. For the screening program to be cost-effective, the cumulative conversion rate required using bevacizumab is 32.2 % and 20.4% at 2 and 5 years respectively. Due to its higher cost, monthly ranibizumab treatment does not reach significance until patients are followed for 10 years. If ranibizumab is given quarterly after the first 3 monthly injections, then the cumulative conversion rate required for cost-effectiveness is 36% at 5 years. For comparison, conversion rates observed in the MARINA and ANCHOR trials are 32.1% to 37.3% at 2 years.
Conclusions: :
Regular OCT screening of the second eyes of patients with unilateral wet AMD is cost effective within 2 years if bevacizumab is used and within 5 years if ranibizumab is given quarterly after the first 3 months, but not if monthly ranibizumab is given continuously after detection of subclinical fluid. Such screening can be expected to lead to better final vision regardless of cost-effectiveness, since virtually all anti-VEGF trials for wet AMD demonstrate that initial visual acuity (VA) is the strongest predictor of final VA.
Keywords: clinical (human) or epidemiologic studies: health care delivery/economics/manpower • age-related macular degeneration • retina