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Swollen, but not tender joints, are independently associated with ultrasound synovitis: results from a longitudinal observational study of patients with established rheumatoid arthritis
  1. Hilde Berner Hammer1,
  2. Brigitte Michelsen2,
  3. Joseph Sexton1,
  4. Ida K Haugen1,
  5. Sella A Provan1,
  6. Espen A Haavardsholm1,
  7. Till Uhlig1,
  8. Tore K Kvien1
  1. 1 Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway
  2. 2 Department of Rheumatology, Hospital of Southern Norway Trust Kristiansand, Kristiansand, Norway
  1. Correspondence to Dr Hilde Berner Hammer, Department of Rheumatology, Diakonhjemmet Hospital, Oslo 0319, Norway; hbham{at}


Objectives Joint swelling and tenderness are considered a proxy for inflammation in patients with rheumatoid arthritis (RA). With ultrasound-detected inflammation as reference, our objectives were to explore on patient and joint level the associations between ultrasound synovitis and joint swelling, tenderness and patient-reported joint pain (PRJP).

Methods 209 patients with established RA were examined six times during 12 months with assessment of 32 joints in upper/lower extremities for joint swelling/tenderness and Grey scale (GS)/power Doppler (PD) synovitis. PRJP was assessed on a manikin. Correlations between different sum scores were at each examination calculated using Spearman’s rho (r), agreement at joint level was examined by Cohen’s kappa and logistic regression models were used to explore the associations between joint assessment and GS/PD scores.

Results At patient level, swollen joints were strongly correlated with GS/PD sum scores (r=0.64–0.88), while tender joints were primarily associated with PRJP (r=0.54–0.68). At joint level, GS/PD pathology had higher agreement with swelling (kappa 0.54–0.57) than tenderness (kappa 0.20–0.21) or PRJP (0.23–0.25). Higher percentages of joints were swollen according to increasing GS/PD scores, independently of joint tenderness. However, joints being tender, but not swollen, were not associated with GS/PD scores. Receiver operating curves showed swollen but not tender joints to be associated with GS/PD scores.

Conclusions Swollen joints were strongly associated with ultrasound detected synovitis at both patient and joint level, while this association was not found for tender joints. These results may question if tender joints reflect ongoing inflammation in established RA.

  • rheumatoid arthritis
  • ultrasound
  • synovitis

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  • Handling editor Josef S Smolen

  • Contributors HBH has made a substantial contributions to the conception and design of the work; the acquisition of data, some of the analysis, interpretation of data for the work and drafted the manuscript. All authors revised the manuscript critically for important intellectual content; given a final approval of the version to be published and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Funding This work was supported by AbbVie, Pfizer and Roche in form of study grants to the Department of Rheumatology, Diakonhjemmet Hospital, Oslo/ Hilde Berner Hammer.

  • Competing interests HBH has received fees for speaking and/or consulting from AbbVie, BMS, Pfizer, UCB, Roche, MSD and Novartis. BM has received fees for consulting/ unrestricted grant from Novartis. JS has no competing interests. IKH has received consulting fees from AbbVie and a research grant from PfizerSella Aarrestad Provan has no competing interests. EAH has received investigator-initiated research funding from Pfizer, UCB, Roche, MSD and AbbVie, honorariums as a speaker from Pfizer, UCB, Roche and AbbVie and honorariums for development of educational material from Pfizer and Eli Lilly and has been in advisory boards for Pfizer, Eli Lilly, Celgene and Janssen-Cilag.TU has no competing interests.TKK has received fees for speaking and/or consulting from AbbVie, BMS, Boehringer Ingelheim, Celgene, Celltrion, Eli Lilly, Hospira, Merck-Serono, MSD, Novartis, Orion Pharma, Pfizer, Roche, Sandoz and UCB and received research funding to Diakonhjemmet Hospital from AbbVie, BMS, MSD, Pfizer, Roche and UCB.

  • Patient consent for publication Not required.

  • Ethical approval information The study was approved by the Norwegian Regional Committee for Medical and Health Research Ethics South East (reference number 2009/1254) and the patients gave their written informed consent according to the Declaration of Helsinki.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information.