Outcomes

The planned IUAT primary and secondary outcomes, including the safety, mRS, and COSMOS patient-centred function.

Primary endpoint

The planned primary endpoint is a composite patient-centred score incorporating patient safety, mRS, and patient function (assessed with the COSMOS score).

Why not mRS alone?

The mRS remains important, but it is insensitive to several outcomes that matter in elective aneurysm treatment. Patients may be independent on mRS but still have cognitive symptoms, fatigue, psychological distress, epilepsy risk or delayed return to work.

IUAT retains mRS as a secondary endpoint but avoids making it the only measure of meaningful outcome.

Secondary endpoints

Planned secondary outcomes include:

• mRS 0–1 and 0–2 at follow-up points
• COSMOS shift analysis
• length of stay and days alive out of hospital
• return to work or role at 3 and 6 months
• angiographic occlusion using Raymond–Roy grading
• retreatment rates
• procedure-related complications
• quality of life using EQ-5D-5L and SF-36
• anxiety and psychological distress using GAD-7 and PHQ-9
• health economic analysis from the NHS perspective
• post-discharge epilepsy diagnosis and antiseizure-medication burden

Blinded adjudication

The protocol proposes central blinded adjudication for clinical events, mRS, COSMOS and angiographic results. This is important because the treating team and patient cannot practically be blinded to clipping or endovascular treatment.