Objective To explore associations between remission, based on clinical and ultrasound definitions, and future good radiographic and physical outcome in early rheumatoid arthritis (RA).

Methods Newly diagnosed patients with RA followed a treat-to-target strategy incorporating ultrasound information in the Aiming for Remission in rheumatoid arthritis: a randomised trial examining the benefit of ultrasound in a Clinical TIght Control regimen (ARCTIC) trial. We defined 6-month remission according to Disease Activity Score, Disease Activity Score in 28 joints-erythrocyte sedimentation rate, American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) Boolean criteria, Simplified Disease Activity Index, Clinical Disease Activity Index and two ultrasound definitions (no power Doppler signal, grey scale score ≤2). Two outcomes were defined: no radiographic progression and good outcome (no radiographic progression+physical function≥general population median), both sustained 12–24 months. We calculated the ORs of these outcomes for the remission definitions.

Results Of 103 patients, 42%–82% reached remission at 6 months, dependent on definition. Seventy-one per cent of patients had no radiographic progression and 37% had good outcome. An association between 6-month remission and no radiographic progression was observed for ACR/EULAR Boolean remission (44 joints, OR 3.2, 95% CI 1.2 to 8.4), ultrasound power Doppler (OR 3.6, 95% CI 1.3 to 10.0) and grey scale remission (OR 3.2, 95% CI 1.2 to 8.0). All clinical, but not ultrasound remission criteria were associated with achievement of a good outcome.

Conclusions Our data support ACR/EULAR Boolean remission based on 44 joints as the preferred treatment target in early RA. Absence of ultrasound inflammation was associated with no radiographic progression.

Trial registration number NCT01205854; Post-results.