Background: Active tuberculosis (TB) in patients with latent tuberculosis infection (LTBI) was associated with use of biological agents for immune-mediated inflammatory disorders (IMIDs). For decreasing active TB, isoniazid prophylaxis therapy was administered before biologic therapy among IMID patients with LTBI. However, for patients who had been received biologics for a long time with unknown status of LTBI or exposure history of active TB, the prevalence of LTBI and efficacy of isoniazid therapy were unclear.
Method: A retrospective cohort study was conducted during 2012-2014 in a tertiary medical center in Taiwan, and the incidence case of active TB was identified by the national TB registration system on October 1, 2015.
Results: All 382 patients with 1532 person-years were followed up, the initial prevalence of LTBI by positive interferon-gamma releasing assay (IGRA+) was 17.5%. The prevalence of LTBI was increased in elder age (>20%, p < 0.05), chronic kidney disease (33%, p < 0.05), metabolic syndrome (26.3%, p < 0.05), but not related to the type of IMIDs or biologics. The crude incidences of TB were increased in elders (53.3/1000 person-year), abnormal chest film (49.6/1000 person-year), administration of tocilizumab (13.6/1000 person-year), and metabolic syndrome (56.1/1000 person-year), respectively. Among patents with LTBI, the incidence of active TB was lower in patients with isoniazid therapy (9.2/1000 person-year, p = 0.02) than without isoniazid therapy (92.2/1000 person-years), regardless the timing of initiating isoniazid therapy (p > 0.05).
Conclusion: Isoniazid therapy can prevent active TB from LTBI despite of the timing of biologics administration.
Keywords: DMARD; Isoniazid; Tuberculosis.
Copyright © 2017. Published by Elsevier B.V.