Model Structure and Perspective

A Markov state transition model was developed to assess the cost-effectiveness of intravitreally administered aflibercept. The Markov model was structured so health states were distributed on the basis of patients’ vision using average VA score (ETDRS letters) at a series of inflection points, including baseline, 12 weeks (treatment efficacy), 1 year (post-treatment efficacy), and 15 years (long-term decline). Because overall vision and relationship with quality of life are functions of vision in both eyes, model health states were defined by patients’ best-corrected VA score of both eyes. At any point in the model, patients are distributed into one of eight mutually exclusive, exhaustive VA health states, defined by ETDRS letters (graphical representation of the model is available in Appendix 2 in the supplementary material). The distribution of patients across each VA health state was estimated using the mean and SD of VA at each point in time and assuming a scaled beta distribution (bound at 0 and 100, as per the ETDRS letter scale). The model allows for selecting various time horizons from 10 years to lifetime, thus providing an adequate time frame to capture all relevant treatment costs and effects [measured as quality-adjusted life years (QALYs)] associated with the interventions. To ensure that the analysis provided a complete overview, various time horizons were considered. The analysis considers recommendations from the French National Healthcare System, Haute Autoritié de Santé (HAS), and includes both direct and indirect costs [28]. Costs and outcomes were discounted at a 4% annual rate per HAS guidelines.