Diagnosis and treatment of latent tuberculosis infection in arthritis patients treated with tumor necrosis factor antagonists in Korea

Tumor necrosis factor (TNF) is essential for host defense against Mycobacterium tuberculosis, and the risk of reactivation of latent tuberculosis infection (LTBI) increases with anti-TNF therapy. This study estimated the prevalence of LTBI and evaluated the safety and completion rate of short-course therapy with isoniazid plus rifampin for 3 months to treat LTBI in a cohort of Korean arthritis patients before initiating anti-TNF therapy. We retrospectively studied the files of 112 consecutive patients to evaluate LTBI before starting anti-TNF drugs. Screening tests were performed, including a tuberculin skin test and chest radiography. LTBI treatment was indicated in 41 patients (37%). Of these, three patients refused the LTBI treatment. Of the 38 patients who underwent LTBI treatment, 36 (95%) took isoniazid plus rifampin for 3 months. Six patients (16%) showed transient elevations of liver enzymes during the LTBI treatment. Overall, 35 patients (92%) completed the LTBI treatment as planned. In conclusion, LTBI was diagnosed in one-third of Korean arthritis patients before initiating anti-TNF therapy. A high percentage of these patients completed 3 months of LTBI treatment with isoniazid plus rifampin without serious complications.