PMD109 - A CANADIAN COST-UTILITY ANALYSIS OF TWO TRABECULAR MICRO-BYPASS STENTS IMPLANTED AT TIME OF CATARACT SURGERY IN PATIENTS WITH MILD-TO-MODERATE OPEN-ANGLE GLAUCOMA

Abstract

To estimate the cost-utility of two micro-bypass trabecular stents (MBTS) implantation at time of cataract surgery versus standard of care (SOC) in the Canadian healthcare setting. A Markov model was designed to track progression of glaucoma through health states defined using Hodapp-Parrish-Anderson stages and death: mild, moderate, advanced, severe/blind glaucoma over a 15-year time horizon. Reduction in intraocular pressure (IOP) and medication use due to MBTS and SOC were identified from randomized controlled trial (RCT) data. Transition probabilities were estimated using IOP-adjusted rate of decline in visual field (VF) loss. A 10% decline in relative treatment effect per year was conservatively assumed for extrapolation of efficacy beyond trial follow-up. Unit costs and utilization of healthcare resources, and progression-related utility scores for the general Canadian population were obtained by literature review and reflect 2017 Canadian costs. IMS Brogan PharmaStat was used to estimate medication costs with wastage. Probabilistic and 1-way sensitivity analyses were conducted to estimate the impact of parameter and methodological uncertainty on costs and quality-adjusted life years (QALYs). The model estimated MBTS therapy was the cost-effective strategy as it was associated with an incremental improvement in quality of life (0.021 QALYs), and an increase in healthcare costs of $213.4 per patient over a lifetime resulting in a cost per QALY of $9,968. Sensitivity analyses showed that results were robust to variations in model assumptions. MBTS implantation as an add-on to cataract surgery was cost-effective in patients with mild-to-moderate OAG in Canada. Clinicians should consider not only upfront costs of add-on MBTS but also long-term savings generated due to slowing of glaucoma progression and reduction in medication use when making optimal therapy decisions.