Safety, effectiveness, and cost-effectiveness of immediate versus delayed sequential bilateral cataract surgery in the Netherlands (BICAT-NL study): a multicentre, non-inferiority, randomised controlled trial.

Background: In an ageing population, efficiency improvements are required to assure future accessibility of cataract care. We aim to address remaining knowledge gaps by evaluating the safety, effectiveness, and cost-effectiveness of immediate sequential bilateral cataract surgery (ISBCS) versus delayed sequential bilateral cataract surgery (DSBCS). We hypothesised that ISBCS is non-inferior to DSBCS, regarding safety and effectiveness, and being superior in cost-effectiveness.

Methods: We did a multicentre, non-inferiority, randomised controlled trial, which included participants from ten Dutch hospitals. Eligible participants were 18 years or older, underwent expected uncomplicated surgery, and had no increased risk of endophthalmitis or refractive surprise. Participants were randomly assigned (1:1) to either the ISBCS (intervention) group or DSBCS (conventional procedure) group, using a web-based system stratified by centre and axial length. Participants and outcome assessors were not masked to the treatment groups because of the nature of the intervention. The primary outcome was the proportion of second eyes with a target refractive outcome of 1·0 dioptre (D) or less 4 weeks postoperatively, with a non-inferiority margin of -5% for ISBCS versus DSBCS. For the trial-based economic evaluation, the primary endpoint was the incremental societal costs per quality-adjusted life-year. All analyses were done by a modified intention-to-treat principle. Costs were calculated by multiplying volumes of resource use with unit cost prices and converted to 2020 Euros (€) and US$. This study was registered with ClinicalTrials.gov, number NCT03400124, and is now closed for recruitment.

Findings: Between Sept 4, 2018, and July 10, 2020, a total of 865 patients were randomly assigned to either the ISBCS group (427 [49%] patients; 854 eyes) or DSBCS group (438 [51%] patients; 876 eyes). In the modified intention-to-treat analysis, the proportion of second eyes with a target refraction of 1·0 D or less was 97% (404 of 417 patients) in the ISBCS group versus 98% (407 of 417) in the DSBCS group. The percentage difference was -1% (90% CI -3 to 1; p=0·526), thereby establishing non-inferiority for ISBCS compared with DSBCS. Endophthalmitis was not observed or reported in either group. Adverse events were comparable between groups, with only a significant difference in disturbing anisometropia (p=0·0001). Societal costs were €403 (US$507) lower with ISBCS than with DSBCS. The cost-effectiveness probability of ISBCS versus DSBCS was 100% across the willingness-to-pay range of €2500-80 000 (US$3145-100 629) per quality-adjusted life-year.

Interpretation: Our results showed non-inferiority of ISBCS versus DSBCS regarding effectiveness outcomes, comparable safety, and superior cost-effectiveness of ISBCS. National cost savings could amount to €27·4 million (US$34·5 million) annually, advocating for ISBCS if strict inclusion criteria are applied.

Funding: Research grant from The Netherlands Organization for Health Research and Development (ZonMw) and Dutch Ophthalmological Society.