Background TNF-α inhibitors are highly effective for signs and symptoms of ankylosing spondylitis (AS) including acute anterior uveitis (AAU). However, there are some concerns that etanercept does not seem to prevent a relapse and may even trigger an attack of uveitis.

Objectives To examine the incidence rate of AAU flares in AS patients during anti-TNF therapy in Slovakia, and to assess whether there is any difference between TNF-α inhibitors.

Methods AS patients on anti-TNF therapy were retrospectively analyzed in database of AS patients with biological therapy in Slovakia. This analysis covered AS patients on infliximab, etanercept, adalimumab and golimumab since March 3rd 2003, when the first patient was initiated on TNF-α blocker until December 31st 2013. Duration of anti-TNF treatment was calculated on patient-years (PYs). The number of attacks of AAU before start and during anti-TNF therapy was assessed by patient history and ophthalmology reports. Incidence of AAU flares was calculated on 100 PYs, and differences between monoclonal antibodies and etanercept were assessed.

Results All together 372 patients with AS with TNF-α inhibitors were analyzed, of them 318 men (85%) and 54 women (15%). The mean age of patients at the time of initiation of TNF-α blockers was 38.9 years (19-72). Total time on biologic treatment was calculated on 1147 patient-years. 78 patients were exposed to infliximab for a total of 279 PYs, 98 patients were exposed to etanercept for 402 PYs, 151 patients were treated with adalimumab 396 PYs, and 45 patients were under the treatment with golimumab 70 PYs. In general, acute uveitis was present at 26.37% of patients in history before starting biologics. There was no significant difference of uveitis history rates between TNF-α blockers. 268 patients (72%) did not have any attacks of uveitis before and during anti-TNF treatment, 78 patients (21%) had uveitis before, but not after treatment, 19 patients (5%) had uveitis before and also after treatment and 7 patients (2%) developed uveitis for the first time after treatment. In generally, uveitis was present less frequently during anti-TNF therapy than in patients' history before the treatment, what may reflect positive effect of TNF-α inhibitors on suppression of AAU. However, patients exposed to etanercept had more frequent attacks of uveitis during the treatment, and also there were more patients on etanercept with the first onset of AAU after the treatment compared to monoclonal antibodies. Incidence of AAU flares after infliximab was calculated on 1.07 per 100 PYs, after adalimumab on 1.51 per 100 PYs, and after golimumab on 2.86 per 100 PYs. Patients treated with etanercept had more frequent flares of AAU (6.96 per 100 PYs).

Conclusions Prevalence of AAU in patients with AS before anti-TNF therapy in Slovak database of patients with biologics was 26.37%, what is expected and comparable result with other epidemiological studies. TNF-α inhibitors reduced reoccurrence of AAU. The frequency of AAU flares during anti-TNF therapy was generally low, and it was less frequent at patients treated with monoclonal antibodies than at patients treated with etanercept.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.5470