Rheumatoid arthritis patients with predominantly tender joints rarely achieve clinical remission despite being in ultrasound remission

Objectives: Given that subjective variables might reduce remission by composite DAS (CDAS), the main objectives were to explore whether RA patients with mainly tender vs mainly swollen joints had differences in patient-reported outcome measures (PROMs), clinical or US assessments or in achieving remission defined by CDAS or US.

Methods: In a Nordic multicentre study, RA patients initiating tocilizumab were assessed by PROMs, clinical, laboratory and US assessments (36 joints and 4 tendons) at baseline, 4, 12 and 24 weeks. Remission was defined according to clinical disease activity index (CDAI)/Boolean or no Doppler activity present. Tender-swollen joint differences (TSJDs) were calculated. Statistics exploring changes over time/differences between groups included Wilcoxon, Mann-Whitney, Kruskal-Wallis and Spearman tests.

Results: One hundred and ten patients were included [mean (s.d.) age 55.6 (12.1) years, RA duration 8.7 (9.5) years]. All PROMs, clinical, laboratory and US scores decreased during follow-up (P < 0.001). During follow-up, tender joint counts were correlated primarily with PROMs [r = 0.24-0.56 (P < 0.05-0.001)] and swollen joint counts with US synovitis scores [r = 0.33-0.72 (P < 0.05-0.001)]. At 24 weeks, patients with TSJD > 0 had higher PROMs and CDAI (P < 0.05-0.001) but lower US synovitis scores (P < 0.05). Remission by CDAI/Boolean was seen in 26-34% and by Doppler 53%, but only 2-3% of patients with TSJD > 0 achieved CDAI/Boolean remission.

Conclusion: Patients with more tender than swollen joints scored higher on subjective assessments but had less US synovitis. They seldom achieved CDAS remission despite many being in Doppler remission. If patients with predominantly tender joints do not reach CDAS remission, objective assessments of inflammation should be performed.

Trial registration: ClinicalTrials.gov, https://clinicaltrials.gov/, NCT02046616.