Background The presence of rheumatoid factor (RF) plays an important role in diagnosis for patients suspected with rheumatoid arthritis (RA) . However, it remains unclear whether RF positivity is related to the effects of treatment with biologic disease-modifying antirheumatic drugs (DMARDS).
Objectives The objective of the current study was to determine whether RF positivity was associated with the effects of treatment with biologic DMARDS among bio-naïve RA patients.
Methods We used demographic and clinical data from the Tsurumai Biologics Communication Registry, which comprises Nagoya University and 20 affiliated hospitals in Japan. Patients aged 20–80 years who fulfilled the ACR 1987 revised classification criteria or the 2010 ACR/EULAR classification criteria for RA were selected; those with prior exposure to biologic DMARDS were excluded. The RF status was divided into negative (0–15 IU/ml) or positive (>15 IU/ml). Multivariate logistic regression analysis was used to assess the association between RF positivity and the possibility of sufficient response to biologic DMARDS treatment, as defined by good response at week 16 in the EULAR response criteria, based on DAS28. Crude and adjusted odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were calculated. Adjustment variables included sex, age, whether or not tumor necrosis factor inhibitor had been used, baseline use of methotrexate (MTX) and glucocorticoids, and baseline stage and class as defined by the Steinbrocker classification.
Results The demographic and disease characteristics of the patients at baseline were comparable between RF-negative (n=120) and RF-positive (n=557) groups. The mean age was 57 years; 81% were women. Patients had longstanding RA (mean 9.3 years), and the baseline DAS28 was 5.1. Among the patients, 80% and 61% received MTX and glucocorticoids, respectively. A good response as per EULAR response criteria was identified in 73 (60.8%) RF-negative patients and 268 (48.1%) RF-positive patients. The crude OR for the association between RF positivity and the possibility of good response as per EULAR response criteria was 0.60 (95% CI 0.40–0.89) compared with RF negativity. After adjustment for the aforementioned covariates, RF-positivity was associated with a decreased possibility of good response to biologic DMARDS compared with RF-negativity (OR 0.64, 95% CI 0.41–0.98).
Conclusions This study demonstrated that RF-positivity was independently associated with a decreased possibility of good response to biologic DMARDS in bio-naïve RA patients.
P.Y. Chang, C.T. Yang, C.H. Cheng, K.H. Yu, Diagnostic performance of anti-cyclic citrullinated peptide and rheumatoid factor in patients with rheumatoid arthritis, Int J Rheum Dis, (2015).
Disclosure of Interest None declared