Concurrent oral 3 - Environmental and genetic factors: OP16. In Patients with Early Inflammatory Polyarthritis, Younger Age, Acpa Positivity, Shared Epitope, And Inefficacy of the First Dmard are Associated with the Need to Start a Biological Therapy: Results from the Norfolk Arthritis Register (NOAR)

BACKGROUND: Biological therapies have been available for the management of rheumatoid arthritis (RA) for almost a decade. The objectives of this study were (i) to identify baseline disease related predictors in patients with early IP for starting biological therapy and (ii) to determine if patients who fail their first non-biologic DMARD (nb-DMARD) within six months are more likely to need biological therapy. METHODS: Consecutive patients with early IP ( greater than or equal to 2 swollen joints for greater than or equal to 4 weeks) from a primary-care based inception cohort (NOAR), recruited between 1990-1994 in the pre-biologic era (cohort 1) and between 2000-2004 in the biologic era (cohort 2), and who used at least one DMARD during follow-up were included in this study. Baseline clinical assessments included the DAS28 and the HAQ-score. Blood was collected to determine CRP, RF and ACPA. The use of DMARDs and biological therapy was recorded at each visit. DMARD failure was defined as: first DMARD stopped due to inefficacy within six months and/or a second DMARD was started within six months after starting the first DMARD. The association of baseline disease characteristics and failure of the first DMARD with the subsequent start of biological therapy was assessed using Cox proportional hazards regression models. Hazard ratios (HRs, 95%CI) were adjusted for age at symptom onset, gender and symptom duration at baseline. For the association between failure of the first DMARD and the use of a biologic, the survival time started six months after starting the first DMARD. RESULTS: In cohort 1 and 2, 40/422 (9.5%) and 45/416 (10.8%) patients, respectively, started receiving biological therapy after a median time since symptom onset of 134 [116-157] and 47 [24-69] months. In both cohorts, ACPA positivity was the strongest predictor for starting biological therapy (cohort 1: HR 7.58, 95%CI 2.75 to 20.85; and cohort 2: HR 4.66, 95%CI 2.23 to 9.75) Patients having two alleles of the SE were also more likely to start biological therapy compared to patients with no SE alleles (cohort 1: HR 3.42, 95%CI 1.42 to 8.23; and cohort 2: HR 3.25, 95%CI 1.25 to 8.47). In cohort 2, younger patients were more likely to start biological therapy (HR 0.97, 95%CI 0.95 to 0.99). In neither cohort did HAQ or DAS28 at baseline predict subsequent biological therapy use. In cohort 2, number of swollen joints and failure of first DMARD within six months due to inefficacy (HR 2.34, 95%CI