Background The main target for patients with rheumatoid arthritis (RA) is to establish a state of remission. Clinical studies demonstrated a disparity between of disease activity and structural damage. Power Doppler (PD) ultrasonography (US) is capable to provide a more accurate measure of disease activity and to predict long-term radiographic outcomes.
Objectives To assess the significance of residual inflammation according to the presence of swollen joint count (SJC) and PD-signals in relation to radiographic progression in patients receiving anti-interleukin (IL)-6 receptor antibody - tocilizumab (TCZ).
Methods Prospective analysis of 36 consecutive RA patients [median age 51 (range 43-57) years; disease duration 54 (24-96) months; disease activity score-28 (DAS28-CRP) 3.9 (2.2-4.6); 72 % female; 82.8% «+» for rheumatoid factor (RF) and anti-citrullinated peptide antibodies (ACCP)] in therapy with TCZ. The patients underwent clinical, laboratory, and US evaluation at baseline and 6 months. US assessment of the wrist joints was performed by a single operator, unaware of clinical data (“Voluson-i” (GE, USA) with transducer (4-13MHz)). Each joint was scored according to the OMERACT definitions of pathology. The residual inflammation was defined using SJC as a measure of clinical inflammation and PD-signals as a measure of imaging activity. Both variables were dichotomised into “non- or low-active” (SJC≤1, PD≤1) and “middle- or high-active” (SJC>1, PD>1). One-year radiographic progression of the hands and feet was defined when the change of the van der Heijde-modified total Sharp score (∆ total Sharp score) more than 0.5 units per year. The functional status assessed by the Health Assessment Questionnaire Disability Index (HAQ).
Results Twenty-one patients (58%) achieved a radiographic remission (∆ total Sharp score < 0.5) at one year, of whom 9 patients (42.8%) had a functional remission (HAQ < 0.5) from baseline to 6 months. Non- or low-active PD-signals and SJC were observed in 8 (22.2%) and 10 (28%) cases at 6 month, respectively. The total Sharp score at one year was significant higher [93 (56-131) vs. 32.5 (19.5-83) units, p<0.04] in patients with middle- or high-active PD-signals (n=27) than in cases with lower imaging activity or the absence of the PD-signals (n=8) at 6 month. Likewise, in patients with non- or low-active SJC at 6 month (n=10) we found lower radiographic progression over one year [55 (31-116) vs. 88.5 (55-130), p<0.205], than those with SJC>1 (n=25). However, it has been shown only tendency, but no significant difference. Furthermore, ∆ total Sharp score was significantly positively correlated with PD-signals of residual inflammation of the wrists at 6 month (r=0.696, p=0.011), but there was not found correlation with SJC status.
Conclusions In TCZ-treated patients the US-imaging activity score appears to be more predictive of radiographic progression than SJC status. PD-signals more than 1 may be useful for identifying individual RA patients at high risk of the progression very early in the disease, before erosions can be detected by X-ray.
Disclosure of Interest None Declared