ObjectiveTo investigate limiting factors of American College of Rheumatology (ACR)/EULAR Boolean remission in rheumatoid arthritis (RA), and compare patients who fulfil the criteria to patients who only partly fulfil the criteria, with respect to imaging inflammation and biologic disease modifying anti-rheumatic drug (DMARD) usage.MethodsPatients with DMARD-naïve RA were treated according to current recommendations in the the ARCTIC trial (Aiming for Remission in rheumatoid arthritis: a randomised trial examining the benefit of ultrasound in a Clinical TIght Control regimen). Limiting factors of reaching ACR/EULAR Boolean remission at 2 years were assessed. Imaging inflammation (ultrasound and MRI) in patients in remission was compared with patients failing to fulfil different components of the criteria. The OR of biologic therapy was calculated using logistic regression.ResultsOf 203 patients, 112 (55%) reached ACR/EULAR Boolean remission; 49 (24%) fulfilled three of four criteria. The main limiting factors were patient global assessment (PGA) (59%) and tender joints (22%). Imaging inflammation was not significantly different for patients in remission and patients not fulfilling the criteria due to elevated PGA and/or tender joints, but higher odds of using biologics (OR 3.63, 95% CI 1.73 to 7.61) were observed.ConclusionsPGA and tender joints were the factors most often limiting achievement of ACR/EULAR Boolean remission. The level of imaging inflammation was not elevated in these patients compared with patients in remission, but the odds of using biologic DMARDs were higher.