Effectiveness and cost-effectiveness of MicroShunt implantation versus standard trabeculectomy for open-angle glaucoma (a SIGHT study): study protocol of a multicentre randomised controlled trial

Abstract

Background Trabeculectomy is the “gold standard” initial surgical procedure for open-angle glaucoma worldwide. During the last decade, the introduction of less invasive procedures, including new bleb-forming surgery such as the MicroShunt, has altered the approach of glaucoma management. At present, there is insufficient evidence comparing the effectiveness between these procedures nor versus trabeculectomy. Furthermore, there is no data available on patient impact and cost-effectiveness. This study aims to address this gap in evidence and establish whether MicroShunt implantation is non-inferior compared to trabeculectomy with regard to effectiveness and whether it is cost-effective. Methods A multicentre, non-inferiority, randomised controlled trial (RCT) studying open-angle glaucoma with an indication for surgery will be conducted. Patients with previous ocular surgery except for phacoemulsification are excluded, as are patients with ocular comorbidity compromising the visual field or requiring a combined procedure. After informed consent is obtained, patients will be randomly allocated to the intervention, a PRESERFLO™ MicroShunt implantation, or the control group, trabeculectomy, using block randomisation (blocks of 2, 4 or 6 patients). In total, 124 patients will be randomised in a 1:1 ratio, stratified by centre. The primary endpoint will be intraocular pressure (IOP) one year after surgery. Secondary outcomes include IOP-lowering medication use, treatment failure, visual acuity, visual field progression, additional interventions, adverse events, patient-reported outcome measures (PROMs), and cost-effectiveness. Study outcomes will be measured up to 12 months postoperatively. Discussion This study protocol describes the design of a multicentre non-inferiority randomised controlled trial. To this date, cost-effectiveness studies evaluating the MicroShunt have not been undertaken. This multicentre RCT will provide more insight into whether MicroShunt implantation is non-inferior compared to standard trabeculectomy regarding postoperative IOP and whether MicroShunt implantation is cost-effective. Trial registration ClinicalTrials.gov, Identifier: NCT03931564, Registered 30 April 2019.

A Brief Review of Historical and Current Trends in Trabeculectomy

“…The inferiority of MicroShunt in this study may be attributed to a lower dosage of MMC (0.2 mg/mL), as other studies have reported better success for the MicroShunt with higher dose of antifibrotic agents 208,214,215 . A new multicenter RCT in The Netherlands will explore the noninferiority of MicroShunt to trabeculectomy with a primary endpoint of IOP reduction 1 year after surgery 216 . The MicroShunt provides significant reduction in IOP and medical therapy with improved safety profile, but longitudinal prospective data on the device will be important in assessing its long-term safety and efficacy in glaucoma treatment.…”

“…208,214,215 A new multicenter RCT in The Netherlands will explore the noninferiority of MicroShunt to trabeculectomy with a primary endpoint of IOP reduction 1 year after surgery. 216 The Micro- Shunt provides significant reduction in IOP and medical therapy with improved safety profile, but longitudinal prospective data on the device will be important in assessing its long-term safety and efficacy in glaucoma treatment.…”