Background Axial spondylarthritis (AxSpA) has been proposed as an umbrella term for ankylosing spondylitis (AS) and non-radiographic (nr) AxSpA. This new concept makes diagnosis of AS possible at an early stage in the absence of radiographic sacroiliitis. Disease burden in AxSpA patients with or without radiographic sacroiliitis have been shown to be similar in different cohorts, which suggest that both diseases should be treated with the same strategy. Recent randomized clinical trials showed that TNF inhibitors (TNFi) are effective also in treating signs and symptoms of nr-AxSpA. However, the efficacy of anti-TNF agents in patients with nr-AxSpA remains to be shown in daily rheumatology practice.

Objectives To compare the efficacy of TNF inhibitors in patients with AS and nr-AXSpA in daily clinical setting

Methods A total of 174 patients with AxSpA (107 M; 40.8±10.0) from two centers, who contribute to TURKBIO, a biological database in Turkey, and who could provide detailed data on imaging for patients with AxSpA, were included in this study. Of these patients 115 had AS according to the modified New York criteria, 59 patients fulfilled the ASAS classification criteria for AxSpA (78% fulfilling the imaging arm).

Results Baseline demographics and clinical characteristics are summarized in the table below. Patients with nr-AxSpA were significantly younger, had a shorter disease duration and had a higher female predominance than patients with AS. After treatment with TNF inhibitors mean BASDAI score decreased significantly from 6.15±1.76 at baseline to 3.28±2.1 at 3 months (p=0.049) in patients with nr-AxSpA; from 5.99±1.69 to 3.05±1.7 (p:0.008) in patients with AS and from 6.05±1.71 to 3.12±1.85 (p=0.001) in the whole group. Minimal clinical response (a decrease of 2 units in BASDAI) was observed in 63% of the patients with nr-AxSpA and in 68% of the patients with AS. Major clinical response (BASDAI 50) was achieved in 49% and 51% of the patients with nr-AxSpA and AS, respectively. Other efficacy measures such as ASAS20 and ASAS40 response were also similar in both groups, but could be performed in only a small number of patients due to missing data.

Conclusions The results of our study suggest that TNFi, which have been clearly shown to be effective in treating signs and symptoms of AS, seem to be equally effective in the treatment of nr-AxSPA.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.5754