Diagnosis and treatment of latent tuberculosis infection in patients undergoing treatment with immunobiologic agents: a four-year experience in an endemic area

OBJECTIVE: To describe the incidence of active tuberculosis and the occurrence of adverse events after isoniazid treatment in patients with latent tuberculosis infection (LTBI) who also had chronic inflammatory diseases and were treated with immunobiologic agents in an endemic area in Brazil. METHODS: The diagnosis of LTBI was based on anamnesis, clinical examination, chest X-ray, and a tuberculin skin test (TST). Patients received prophylactic treatment (isoniazid for six months) in accordance with the Brazilian guidelines. RESULTS: A total of 101 patients were evaluated between July of 2011 and July of 2015. Of those, 55 (54.46%) were women (mean age, 53.16 ± 1.76 years) and 46 (45.54%) were men (mean age, 45.39 ± 2.13 years). A total of 79 patients (78.22%) were being treated with immunobiologic agents and 22 (21.78%) were being treated with immunomodulatory or immunosuppressive agents. In the screening for LTBI, 53 patients (52.48%) had a TST induration ≥ 10 mm. Chest X-ray findings consistent with LTBI were observed in 36 patients (35.64%). Isoniazid preventive therapy was effective in 96 (95.05%) of the 101 patients evaluated. It is of note that 84 (83.17%) of the patients experienced no adverse effects from the use of isoniazid and that 83 (98.81%) of those patients completed the prophylactic treatment (p = 0.002). Active tuberculosis was diagnosed in 5 (6.33%) of the 79 patients treated with immunobiologic agents and in 1 (4.55%) of the 22 patients treated with other immunomodulators/immunosuppressants. CONCLUSIONS: A six-month course of isoniazid proved to be safe and effective in the treatment of LTBI, which is essential to reducing the risk of developing active tuberculosis.