Comparative Cost-Effectiveness of Xen45 Gel Stent versus Trabeculectomy in the US Medicare System.

Abstract

Purpose: To assess the cost-effectiveness of Xen45 Gel Stent (XGS) compared with trabeculectomy for the surgical management of open-angle glaucoma (OAG) in the US Medicare system.

Design: Cost-utility analysis using safety and efficacy results of a randomized controlled trial (RCT) and other pivotal RCTs.

Subjects: Markov model cohort of adult patients with OAG METHODS: Open-angle glaucoma treatment costs and effects were analyzed with a deterministic model over a 1-year horizon using TreeAge software. Health states included the Hodapp-Parrish-Anderson glaucoma stages (mild, moderate, advanced, blind) and death. Treatment effect was measured as mean number of ocular hypotensive medications and reduction in intraocular pressure, which had a direct impact on transition probabilities between health states. Scenario analyses with future projections were also performed at 2, 5, 10, and 20 years. One-way sensitivity and probabilistic sensitivity analyses were conducted to assess the impact of additional variables, including disutility of XGS relative to trabeculectomy and number of follow-up visits. Both treatment arms were subject to complication and reoperation rates, which were factored in the model.

Main outcome measures: Incremental cost per quality-adjusted life-year (QALY) gained at a willingness-to-pay threshold of USD 50 000 per QALY.

Results: At 1 year, the expected total cost for XGS was USD 10512 compared with USD 8649 for trabeculectomy. Xen45 Gel Stent yielded 0.8602 QALYs at the 1-year horizon, compared with 0.8523 for trabeculectomy, resulting in an incremental cost-effectiveness ratio (ICER) of USD 236629 per QALY. Xen45 Gel Stent became dominated by trabeculectomy at 5 years, meaning it had higher costs and worse outcomes. When XGS was given half the follow-up rate of trabeculectomy at 1-year, trabeculectomy remained the cost-effective option as the ICER of XGS was USD 200634 per QALY. Trabeculectomy remained cost-effective even when there was no perioperative disutility applied to XGS. Probabilistic sensitivity analysis showed that trabeculectomy was cost-effective in 88.4% of iterations and dominant in 45.8%.

Conclusions: Xen45 Gel Stent does not appear to be cost-effective compared to trabeculectomy in the surgical management of glaucoma, even accounting for the purported advantages of less follow-up and decreased postoperative disutility.

Financial disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.