A cost-effectiveness analysis of iStent inject combined with phacoemulsification cataract surgery in patients with mild-to-moderate open-angle glaucoma in France

OBJECTIVE: To investigate the cost-effectiveness of implementing iStent inject trabecular bypass stent (TBS) in conjunction with cataract surgery (Cat Sx) in patients with mild-to-moderate glaucoma from a societal perspective in France. The secondary objective was to explore the economic impact of iStent inject TBS in patients who comply to different degrees with their anti-glaucoma medications. METHODS: A previously published Markov model was adapted to estimate the cost-effectiveness of treatment with iStent inject TBS + Cat Sx versus Cat Sx alone over a lifetime time horizon in patients with mild-to-moderate open-angle glaucoma in France. Progression was modeled by health states reflecting increasing stages of vision loss. Disease progression was obtained from the two-year randomized clinical trial assessing safety and effectiveness of both interventions. French specific health-state utilities and costs were obtained through a targeted literature review. Model structure and inputs were validated by French ophthalmologists. Outcomes were expressed as incremental cost per quality-adjusted life-year (QALY) gained. The robustness of results was tested through sensitivity analyses. RESULTS: iStent inject TBS + Cat Sx reduced the number of medications needed and risk of blindness. Incremental cost and QALYs were €75 and 0.065 leading to an incremental cost-effectiveness ratio (ICER) of €1,154/QALY gained. ICER ranged from dominating for non-persistent patients to €31,127 patients fully persistent with their medication regime. Results from one-way sensitivity analysis had a maximum ICER of €29,000 when varying input parameters. iStent inject TBS + Cat Sx had an 86% chance of being cost-effective at a willingness-to-pay threshold of €30,000 per QALY gained. CONCLUSION: Results demonstrate that iStent inject TBS + Cat Sx is a cost-effective intervention for intraocular pressure reduction when compared to Cat Sx alone in France.