Background Simplified measures to quantify rheumatoid arthritis (RA) disease activity are increasingly used. The minimally clinically important differences (MCID) for some measures, such as the clinical disease activity index (CDAI), have not been well-defined in real-world clinic settings, especially for early RA patients with low/moderate disease activity. Methods Data from Canadian Early Arthritis Cohort patients were used to examine absolute change in CDAI in the first year after enrollment, stratified by disease activity. MCID cutpoints were derived to optimize the sum of sensitivity and specificity versus the gold standard of patient self-reported improvement or worsening. Specificity, positive predictive value and negative predictive values were calculated against patient self-reported improvement (gold standard) and for change in pain, HAQ and DAS28 improvement. Discrimination was examined using area under receiver operator curves (ROC). Similar methods were used to evaluate MCIDs for worsening for patients who achieved low disease activity. Results A total of 578 patients (mean (SD) age 54.1 (15.3) years; 75% women, median (IQR) disease duration 5.3 (3.3, 8.0) months) contributed 1169 visit pairs to the improvement analysis. The MCID cutpoints for improvement were 12 (patients starting in high disease activity, CDAI>22), 6 (moderate, CDAI 10–22), and 1 (low disease activity, CDAI <10). Performance characteristics were acceptable using these cutpoints for pain, HAQ, and DAS28. The MCID for CDAI worsening among patients who achieved low disease activity was 2 units. Conclusions These minimally important absolute differences in CDAI can be used to evaluate improvement and worsening and increase the utility of CDAI in clinical practice.

Although seronegative subjects with EIA have higher baseline DAS28 compared to seropositive subjects, they have a good response to treatment and are less likely to develop erosive disease during followup.

On average, patients with ERA were risk tolerant, but important differences in preferences were identified. In particular, a subgroup of patients may prefer to avoid treatments with a possible increased risk of cancer/infection if other effective options are available.

ObjectiveTo determine the comparative effectiveness of oral versus subcutaneous methotrexate (MTX) as initial therapy for patients with early rheumatoid arthritis (ERA).MethodsPatients with ERA (symptoms ≤1 year) initiating MTX therapy were included from a multicentre, prospective cohort study. We compared the effectiveness between starting with oral versus subcutaneous MTX over the first year. Longitudinal multivariable models, adjusted for potential baseline and time-varying confounders, were used to compare treatment changes due to inefficacy or toxicity and treatment efficacy (Disease Activity Score-28 (DAS-28), DAS-28 remission and Health Assessment Questionnaire-Disability Index (HAQ-DI)).Results666 patients were included (417 oral MTX, 249 subcutaneous MTX). Patients prescribed subcutaneous MTX were prescribed a higher dose of MTX (mean dose over first three months 22.3 mg vs 17.2 mg/week). At 1 year, 49% of patients initially treated with subcutaneous MTX had changed treatment compared with 77% treated with oral MTX. After adjusting for potential confounders, subcutaneous MTX was associated with a lower rate of treatment failure ((HR (95% CI) 0.55 (0.39 to 0.79)). Most treatment failures were due to inefficacy with no difference in failure due to toxicity. In multivariable models, subcutaneous MTX was also associated with lower average DAS-28 scores (mean difference (−0.38 (95% CI −0.64 to −0.10)) and a small difference in DAS-28 remission (OR 1.2 (95% CI 1.1 to 1.3)). There was no significant difference in sustained remission or HAQ-DI (p values 0.43 and 0.75).ConclusionsInitial treatment with subcutaneous MTX was associated with lower rates of treatment changes, no difference in toxicity and some improvements in disease control versus oral MTX over the first year in patients with ERA.

ObjectiveTo evaluate the reliability of concurrent flare identification using 3 methods (patient, rheumatologist and Disease Activity Score (DAS)28 criteria), and construct validity of candidate items representing the Outcome Measures in Rheumatology Clinical Trials (OMERACT) RA Flare Core Domain Set.MethodsCandidate flare questions and legacy measures were administered at consecutive visits to Canadian Early Arthritis Cohort (CATCH) patients between November 2011 and November 2014. The American College of Rheumatology (ACR) core set indicators were recorded. Concordance to identify flares was assessed using the agreement coefficient. Construct validity of flare questions was examined: convergent (Spearman's r); discriminant (mean differences between flaring/non-flaring patients); and consequential (proportions with prior treatment reductions and intended therapeutic change postflare).ResultsThe 849 patients were 75% female, 81% white, 42% were in remission/low disease activity (R/LDA), and 16–32% were flaring at the second visit. Agreement of flare status was low–strong (κ's 0.17–0.88) and inversely related to RA disease activity level. Flare domains correlated highly (r's≥0.70) with each other, patient global (r's≥0.66) and corresponding measures (r's 0.49–0.92); and moderately highly with MD and patient-reported joint counts (r's 0.29–0.62). When MD/patients agreed the patient was flaring, mean flare domain between-group differences were 2.1–3.0; 36% had treatment reductions prior to flare, with escalation planned in 61%.ConclusionsFlares are common in rheumatoid arthritis (RA) and are often preceded by treatment reductions. Patient/MD/DAS agreement of flare status is highest in patients worsening from R/LDA. OMERACT RA flare questions can discriminate between patients with/without flare and have strong evidence of construct and consequential validity. Ongoing work will identify optimal scoring and cut points to identify RA flares.