Background A published report concluded AS patients with a disease duration (DisDur) <10 yrs had a better response to anti-TNF treatment than those with DisDur >10 yrs. 
Objectives To investigate the relationship between DisDur, baseline (BL) characteristics, and treatment responses in patients with AS.
Methods Data pooled from 4 clinical trials (placebo [PBO] or sulfasalazine [SSZ] versus etanercept [ETN]) were analyzed in 4 DisDur categories* and analyzed by age at diagnosis (≤40 or >40 yrs). Analyses conducted using Chi-Square tests and ANCOVA models.
Results 1281 patients analyzed; BL increasing age, decreasing age at diagnosis, and BL increasing BASFI significantly correlated with increasing DisDur categories (P<0.05). A higher % of patients responded to ETN compared to SSZ and PBO in all outcome measures and all DisDur categories. At Wk 12, patients with shorter DisDur had a tendency toward better response with ETN for most dichotomous outcomes, but not SSZ or PBO. This trend was significant for ETN when analyzing patients ≤40 yrs old at diagnosis. No significant differences were observed across DisDur for Wk 12 continuous outcomes (ASDAS, BASDAI, BASFI, etc.).
Conclusions Regardless of the time from diagnosis, and thus treatment initiation, ETN is more effective in patients with active AS compared to SSZ and PBO. Patients treated with ETN with DisDur ≤2 appeared to have the highest treatment response. Additional analyses are needed to further investigate the benefits of early treatment in AS.
*DisDur categories analyzed as non-ordered, nominal using CMH test of general association and as ordered (trend) using CMH test of non-zero correlation.
Rudwaleit et al. Ann Rheum Dis 2004;63:665–670.
Disclosure of Interest X. Baraliakos: None Declared, A. Koenig Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, H. Jones Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, A. Szumski Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, D. Collier Shareholder of: Amgen Inc, Employee of: Amgen Inc, E. Bananis Shareholder of: Pfizer Inc, Employee of: Pfizer Inc