PMD13 - A Canadian Cost-Utility Analysis of two Trabecular Micro-Bypass Stents in Patients with Mild-to-Moderate Open-Angle Glaucoma

Abstract

To estimate the cost-utility of two micro-bypass trabecular stents (MBTS) implantation 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 MBTS randomized clinical trials and meta-analyzed. 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 meta-analysis showed a relative reduction of 1.13 medications/patient and an IOP change of -1.10 mmHg at 36 months favoring MBTS. The model estimated MBTS therapy was the dominant strategy as it was associated with an incremental improvement in quality of life (0.071 QALYs), and a decrease in healthcare costs of $2,995 per patient over a lifetime. Sensitivity analyses showed that results were robust to variations in model assumptions. The costs of the MBTS procedure are expected to be recouped over a few years due to decreased medication use and downstream procedures avoided. Together with the quality of life gains expected with MBTS, it becomes increasingly cost-effective with longer time horizons as it dominates SOC after 2.9 years.