P324 Tuberculosis infection under anti-TNF therapy – should we be looking for it?

Abstract

Background: Anti-tumour necrosis factor (TNF) therapy has revolutionised the treatment of inflammatory bowel disease. However, a major concern is the increased risk of developing tuberculosis (TB), which requires diagnosis and treatment of latent TB infection (LTBI) before initiation of anti-TNF agents. Currently, no recommendations exist regarding the need to regularly re-test patients for latent TB during treatment. We aimed to assess the incidence and to identify risk factors for newly acquired TB infection in patients under anti- TNF agents. Methods: Adult patients under anti-TNF therapy for at least 12 months were retrospectively assessed. Patients with a negative pre-treatment interferon-γ releasing assay (IGRA) that repeated IGRA during anti-TNF treatment were reviewed. Patients with a pre-treatment positive IGRA were excluded. Results: Out of 244 patients under anti-TNF agents (124 infliximab, 120 adalimumab), 87 patients were included. Patients had a mean age of 40 ± 14 years, 64.4% were females, 93.1% were under infliximab and 64.4% had Crohn's disease. Subsequent positive IGRA was identified in 9 patients (10.3% of our sample, 3.7% of all patients under anti-TNF therapy in our centre), of which 3 had active TB and 6 had LTBI. When comparing patients with and without subsequent positive IGRA, no differences were found regarding age (39.6 vs. 36.7 years, p = 0.991) or gender (66.7% vs. 64.1% females, p = 0.999). Patients with subsequent positive IGRA have had close contact with patients with TB more frequently (22.2% vs. 0.0%, p = 0.010), however no differences were found regarding travels to TB-endemic areas (11.1% vs. 7.7%, p = 0.548), professional risk for TB infection (11.1% vs. 9.0%, p = 0.999), concomitant treatment with immunosuppressants (77.7% vs. 71.8%, p = 0.999), use of systemic steroids during anti-TNF treatment (33.3% vs. 35.9%, p = 0.999), diabetes mellitus (11.1% vs. 5.1%, p = 0.429) or active smoking (22.2% vs. 20.5%, p = 0.999). Furthermore, no differences were found in the duration of treatment at the time of subsequent IGRA (30.2 ± 26.7 vs. 42.5 ± 30.1 months, p = 0.640). Conclusions: In patients under anti-TNF therapy, at least 3.7% of patients have a subsequent positive IGRA after treatment beginning. In our sample, only close contact with patients with TB was associated with a subsequent positive IGRA. Therefore, considering that infection during treatment is present in a non-negligible percentage of patients, and most of the classical risk factors cannot be used to identify at-risk patients, physicians may consider to routinely repeat IGRA in patients under anti-TNF therapy.