Farideh Alasti

INTRODUCTION: Although the prognostic value of rheumatoid factor (RF) and autoantibodies against citrullinated proteins (ACPAs) in patients with rheumatoid arthritis (RA) is well established, their association with RA disease activity remains unclear. Here, we investigate this association in a large study using data from clinical trials. METHODS: We used baseline data from four recent randomized controlled clinical trials of RA. We investigated individual and composite measures of disease activity. The relationship of RF and ACPAs with these measures was investigated by using stratified analysis (comparing four groups of patients according to the presence or absence of RF and ACPAs) and matched analysis (disease activity levels compared between patients negative and patients highly positive for one autoantibody who were matched for levels of the other autoantibody as well as for age, gender, and duration of RA). RESULTS: A total of 2118 patients were analysed in the different cohorts. In the stratified analysis, RF(+) patients, regardless of ACPA status, had the highest levels of disease activity, whereas ACPA(+) patients had disease activity that was similar to or lower than that of ACPA(-) patients, both in the presence and in the absence of RF. When matched for ACPA levels, patients with highly positive RF had significantly higher disease activity for all composite indices compared with patients who were RF(-) (P = 0.0067), whereas ACPA-highly-positive and ACPA-negative patients matched for RF levels had similar disease activity, again even with the tendency toward lower disease activity for ACPA(+) patients (P = 0.054). CONCLUSION: The data presented suggest that the presence of RF has a clear association with higher levels of disease activity but that the presence of ACPAs has not and even appears to be associated with lower disease activity.

BACKGROUND: Despite modern therapeutics and treatment strategies, a subset of rheumatoid arthritis (RA) patients remains insufficiently responsive to multiple therapies. Here, we identify predictors of such refractory RA ("reRA"). METHODS: Patients from a longitudinal academic clinical database with reRA (defined as failing to reach the treatment target of at least low disease activity with ≥3 DMARD courses, including ≥1 biological, over a total of ≥18 months) were compared to patients who did respond within the first two treatments (treatment amenable RA, "taRA"). We performed logistic regression analysis to identify risk factors for refractory disease, and several sensitivity analyses concerning different potential definitions for reRA to confirm the robustness of the results; key findings were also validated in an independent community cohort. RESULTS: We enrolled 412 patients, of whom 70 were reRA and 102 taRA; 240 patients fulfilled neither definition. ReRA patients were more frequently female (92.9 vs. 70.6%, p < 0.001), younger (44.37 vs. 51.14 years, p = 0.002), and had higher CDAI levels at first presentation (26.06 vs. 15.39, p < 0.001). Treatment delay was significantly longer for reRA than for taRA (3.17 vs. 1.45 years, p = 0.001). In multivariable analyses, treatment delay, female gender and higher disease activity remained as independent predictors of refractory disease. Based on the identified predictors, we developed a matrix model for risk of future reRA. CONCLUSIONS: Our data identified delay to initial treatment, female gender and higher disease activity as important predictors of a later refractory course of RA. Delay of treatment initiation is the single most important modifiable risk factor of refractory disease.