P1111 Prevalence and risk factors for active tuberculosis in Tunisian IBD patients

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Abstract Background IBD patients are at risk of active tuberculosis,given the use of immunosuppressive treatments.Our country is an endemic region for tuberculosis,which may increase this risk. The aim of our study was to estimate the prevalence of active tuberculosis in IBD patients with prior screening and to investigate associated risk factors. Methods This was a retrospective and descriptive study,including all IBD patients admitted in the department,who had a screening for latent tuberculosis,over a 10-year period[2012-2022].Patients with less than 12 months' follow-up were excluded. Results We included 100 patients, 52 men and 48 women.Crohn's disease(CD)was present in 86% of cases,and ulcerative colitis in 14%.CD was predominantly ileocolic (47%).The phenotype of luminal CD was inflammatory, stenosing and fistulizing in 36.6%,28% and 35.4% of cases respectively.Anoperineal involvement was present in 41.9% of CD patients.At the time of screening, patients were on salicylates, steroids and thiopurines in 13%,27% and 22% of cases respectively.Body mass index median was 22.7kg/m².Two-thirds of patients(65%)were in a flare-up at the time of screening,with 50.8% in moderate severity, and 3.1% in severe acute colitis.Ninety patients had a negative TST.The quantiFERON test was positive in 9 patients and indeterminate in one,in four of them, the TST was also positive. There were no abnormalities on chest X-rays in all patients.Fifteen patients received chemoprophylaxis, mainly because of suspected latent tuberculosis, but also because of severe undernutrition despite a negative workup in 3 patients.Chemoprophylaxis was isoniazid monotherapy for 9 months,except for 3 patients who received isoniazid and rifampicin dual therapy for 3 months.The prevalence of active tuberculosis in our patients was 11%.The median time from onset of tuberculosis to screening was 12 months.Almost all patients were on anti-TNFα monotherapy(n=4) or combotherapy(n=6).One patient was on azathioprine only. Chest CT scans showed signs suggestive of tuberculosis in only 2 patients.Among patients who developed active tuberculosis, 2 had previously received chemoprophylaxis for a positive TST. In a univariate study,we analyzed all variables for risk factors associated with the occurrence of tuberculosis in our patients.Apart from the use of anti-TNF drugs(p=0.03),no statistically significant associations were found:severity of relapse during screening(p=0.3),undernutrition as evidenced by a low BMI(p=0.92),albuminemia(p=0.77),C reactive protein(p=0.8). Conclusion The median delay to onset of active tuberculosis suggests post-screening transmission.This is further evidence of the need to shorten the time required for systematic updating of the tuberculosis work-up in endemic countries.