Background:Several previous observational studies have suggested that patients with anti-Ro/SSA antibody-positive rheumatoid arthritis (RA) may respond poorly to treatment, including tumor necrosis factor inhibitors1. However, its influence on methotrexate (MTX) treatment, which is the anchor drug of treat-to-target strategy in RA treatment, remains unclear.Objectives:We compared the clinical response to MTX in both anti-Ro/SSA antibody-positive and -negative patients with MTX-naiive RA and investigated the reasons for the difference in response.Methods:We recruited 210 consecutive patients with RA who were newly started on MTX in this retrospective cohort study. The effect of the presence of anti-Ro/SSA antibodies on achieving low disease activity (LDA) of DAS28-CRP at six months after initiating MTX was investigated by using logistic regression analysis. CDAI, SDAI, concomitant using DMARDs and painkillers, patient’s and evaluator’s VAS, tender joint counts, and swollen joint counts at six months were also compared between the anti-Ro/SSA-positive patients and -negative patients. Missing data were imputed by using multiple imputations before multivariate analysis.Results:32 anti-Ro/SSA antibody-positive patients and 178 anti-Ro/SSA antibody-negative patients were included. The rate of achieving DAS28-LDA at six months was significantly lower in the anti-Ro/SSA antibody-positive patients than those in the anti-Ro/SSA antibody-negative patients (56.2% versus 75.8%, P=0.03). in the logistic regression analysis, the presence of anti-Ro/SSA antibodies was an independent negative predictor for achieving DAS-28-LDA at six months (OR:0.431, 95%CI: 0.190-0.978, P=0.044) (Table1). Anti-Ro/SSA antibody-positive patients had significantly higher patient’s VAS at six months (median [IQR]: 22 [15-41] vs 19 [5-30], P=0.038), and prescribed NSAIDs (37.5% vs 18.0%, P=0.018). CDAI and SDAI after six months were not significantly different between the group.Conclusion:The presence of anti-Ro/SSA antibodies might be one of the predictive factors for the insufficient response to treat to target strategy in RA treatment. Residual pain was suspected as one of the mechanisms contributing to the lesser clinical response of MTX in anti-Ro antibody-positive RA.References:[1]Ran Matsudaira wt al. J Rheumatol 2011;38(11):2346-54Table 1.Logistic regression analysis for the rate of achieving DAS28 low disease activity at six months.Risk factor Odds ratio95%CIP valueAge at onset0.9930.968-1.0180.586Sex (woman)0.6430.300-1.3840.258RF-positive1.9620.853-4.5110.112ACPA-positive0.5520.225-1.3510.192Anti-Ro/SSA antibody-positive0.4310.190-0.9780.044Disclosure of Interests:None declared
Novel optical spectral transmission (OST)-guided versus conventionally disease activity-guided treatment: study protocol of a randomized clinical trial on guidance of a treat-to-target strategy for early rheumatoid arthritis