Estimating the yearly number of eyes with treatable neovascular age-related macular degeneration using a direct standardization method and a markov model.

PURPOSE To estimate the number of treatable eyes with neovascular subfoveal age-related macular degeneration (ARMD) in France. METHODS A literature search for studies documenting neovascular ARMD incidence rates and direct standardization according to age and gender were performed. Projection to the year 2025 was based on OECD (Organization for Economic and Co-operation Development) data. A cohort of patients aged 75 years was simulated by a seven-state Markov model. The mean treatment duration was fixed arbitrarily at 2 years. The probability of ARMD in the second eye was fixed at 30% at 5 years. Monthly mortality incidence was modeled from INSEE (Institut National de la Statistique et des Etudes Economiques) mortality tables. The time horizon of the model was 25 years. Sensitivity analyses were performed. RESULTS Based on the Rotterdam Study, 30,192 citizens per year will develop ARMD in one eye. Among them, 17,585 will be neovascular and 13,805 neovascular subfoveal ARMD. Taking into account the second eye, mortality, and a 2-year treatment duration, the number of neovascular subfoveal treatable eyes yearly would be 37,019 by 2025. Treatment duration was the most sensitive parameter. The number of eyes would be 18,899, 53,204, 67,535, and 80,162, for treatment lasting 1, 3, 4, and 5 years, respectively. A 2% yearly increase is expected up to 2025, due to population aging and the 1950s baby boom. CONCLUSIONS According to the study model, the yearly number of subfoveal neovascular ARMD treatable eyes in France will be 37,019 by 2025. Average treatment duration was the most sensitive parameter.