OBJECTIVES: Building a cost-effectiveness model in the ophthalmology disease area is challenging due to the ambiguity of utility estimates that comes from the bilateral nature of the disease. With the availability of a recent study that provides utility estimates accounting for the bilateral nature of vision, we evaluated the impact of different utility values on a cost-effectiveness model in diabetic macular edema.

METHODS: We built a cost-effectiveness model between aflibercept and ranibizumab under two different scenarios using The Diabetic Retinopathy Clinical Research Network’s Protocol T clinical trial data: using worse-seeing eye utility value or using better-seeing eye and worse-seeing eye interaction utility value. Utility values were calculated by the defined visual acuity using the regression analyses from Hodgson et al (2017). Treatment-related costs, adverse event management, and visual acuity related healthcare resource costs were based on a previous model after adjusting for current inflation (2022 US dollars).

RESULTS: Under both scenarios, total 2-year costs for aflibercept and ranibizumab were $219,054 and $222,827, respectively. Total QALY differences between the two different utility values were 0.88 for aflibercept and 0.82 for ranibizumab (one-eye utility value, two-eye utility value: aflibercept 18.50, 17.63; ranibizumab 18.42, 17.60). The incremental QALYs differences between aflibercept and ranibizumab were -0.09 and -0.03 for the one-eye utility value and two-eye utility value, respectively.

CONCLUSIONS: Our model suggests that using one-eye utility values in cost-effectiveness analysis may be misleading. With limited data available on the visual acuity of the fellow-eye, our model assumed the fellow-eye is not treated and follows the natural progression of diabetic macular edema. However, in clinical practice, patients with fellow-eye disease involvement receive treatment for that eye. For further analysis, we suggest building a two-eye model to reflect actual treatment procedure and to make an accurate comparison between the two utility assessment approaches.