P369 Mycobacterium tuberculosis infection among patients with inflammatory bowel disease under biologics: experience of Croatian Tertiary Centre

D. Ogresta, A. Bišćanin, V. Tomašić, Z. Dorosulić, D. Kralj, J. Forgač, P. Ćaćić, I. Lerotić, D. Hrabar

Department of Gastroenterology and Hepatology, University Hospital Center Sestre milosrdnice, Zagreb, Croatia

Background

Mycobacterium tuberculosis infection (TB) causes a huge number of deaths in the world. A majority (95%) of infections remain asymptomatic, defined as latent tuberculosis (LTB). The estimated incidence rate of TB in Croatia is 10.6 cases per 100 000 inhabitants. Patients with inflammatory bowel diseases (IBD) usually require immunosuppressive therapies which puts them at higher risk for infection. LTB diagnosis and prophylactic treatment are recommended for all patients starting biologics.

Methods

A single-centre retrospective study in the continental part of Croatia included all IBD patients who started treatment with biologics and have presented with TB or LTB from January 2016 till September 2019. The aim was to evaluate the prevalence of LTB among patients with IBD before starting biologic therapy, and TB reactivation during treatment with biologics. All patients underwent Interferon Gamma Release Assay (IGRA) and X-ray. Active infection was excluded or diagnosed using clinical history, bronchoscopy, CT scan and sputum stain for Mycobacteria.

Results

Study population included 74 patients treated with biologics: 51% female, 73% Crohn’s disease (CD); 37% starting adalimumab, 29% infliximab, 19% ustekinumab and 15% vedolizumab. Prevalence of LTB was 8.1% (6 patients), and all patients underwent isoniazid prophylaxis for 9 months except one patient treated with conventional immunomodulatory therapy which failed prophylactic therapy with both isoniazid and rifampin (liver injury). Among patients with adequate chemoprophylaxis, two patients later on started with anti-TNF therapy (adalimumab), two patients with vedolizumab and one with ustekinumab. One patient with CD and negative LTB screening developed pulmonary TB during induction with infliximab (1 month after initiation); after successful treatment with conventional fourfold therapy, the patient was switched to vedolizumab. During the observational period (median 16 months), all IBD patients with LTB as well with cured TB were in clinical and biochemical remission, without signs of TB (re)activation.

Conclusion

Our study has demonstrated that prevalence of LTB among our IBD patients starting biologics was significant (8.1%). Treatment with vedolizumab, ustekinumab and anti-TNF (adalimumab) after isoniazid chemoprophylaxis appears to be safe during the observational period, without signs of TB reactivation.