Background Intra-articular (i.a.) corticosteroid injections are in many countries an integral part of rheumatoid arthritis (RA) treatment. Ultrasonography (US) is increasingly used in the management of RA as a tool to select joints for i.a. injections. How selection of joints based on US information affects distribution of injections has not been previously studied. US can detect joints with subclinical inflammation, however, it is unknown whether there is any added value of injecting these joints.
Objectives We aimed to explore how US information influences the selection of joints for corticosteroid injection therapy. Additionally, we wanted to examine the efficacy of injecting joints with subclinical inflammation detected by US in terms of reduction of subclinical inflammation and prevention of clinical synovitis.
Methods In the ARCTIC trial, DMARD-naive RA patients fulfilling the 2010 ACR/EULAR criteria were randomised 1:1 to follow-up with or without US. In both arms the same DMARD treatment strategy was applied, and clinically swollen joints were treated with i.a. steroids when indicated. In the US arm, clinicians could also inject non-swollen joints with PD activity. Patients were assessed at 13 visits during 2 years of follow-up and injections could be performed at all visits. Distribution of injections in patients followed with and without US was assessed. The proportion of patients with any injection was compared between arms using logistic regression, adjusted for gender. In addition, we examined the effect of injections in clinically non-swollen joints with PD ≥2 (range 0–3) by comparing clinical joint swelling and estimated mean change in PD activity at the next visit in injected versus non-injected joints. We used logistic and linear mixed model with random intercept by patient in order to adjust for within-patient dependencies.
Results 230 patients were included (US arm 118, conventional arm 112). Mean (SD) age was 50.6 (13.3)/ 52.3 (14.1) years, 71/51% were females and mean (SD) baseline DAS was 3.5 (1.2)/3.4 (1.2) in the US/conventional arms.  More injections occurred in the US arm than in the conventional arm (770 vs 548), especially in intercarpal (58 vs 5) and MTP joints (200 vs 104) (Table 1). In the US arm, 193 joints were clinically non-swollen, but had PD score ≥2. Of these, 77 joints were injected. 72/77 injected joints (93.5%) remained non-swollen at next visit compared to 88/116 non-injected joints (75.9%), with an odds ratio of 3.97 (CI: 1.25–12.57, p=0.019, NNT:6). Estimated mean (SE) reduction of PD activity was 2.3 (0.1) compared to 2.0 (0.1) in injected versus non-injected joints (p<0.001).
Conclusions Our study shows that follow-up with US may lead to an increased number of joint injections with a different distribution of injected joints compared to follow-up without US. Joints with subclinical inflammation were more likely to remain non-swollen at next visit if injected. However, as the number of joints needed to treat to prevent one swollen joint was six, the clinical relevance of injecting joints with subclinical inflammation may be questionable.
Haavardsholm EA et al., BMJ 2016;354:i4205.
Disclosure of Interest L. Nordberg: None declared, S. Lillegraven: None declared, A.-B. Aga: None declared, I. Olsen: None declared, E. Lie: None declared, H. Hammer Consultant for: Consultant for AbbVie, Pfizer, BMS, Roche, UCB, T. Uhlig: None declared, D. van der Heijde: None declared, T. Kvien: None declared, E. Haavardsholm Grant/research support from: Pfizer, MSD, UCB, AbbVie, Roche