Risk of Tuberculosis Development in Patients with Rheumatoid Arthritis Receiving Targeted Therapy: a Prospective Single Center Cohort Study

BACKGROUND: Patients with rheumatoid arthritis (RA) undergoing targeted therapy have a higher risk of developing tuberculosis (TB). This requires diagnosis and treatment of latent tuberculosis infection (LTBI). We aimed to evaluate whether diagnosis and treatment of LTBI in RA are effective in Korea, and to estimate the risk of TB development by calculating the incidence rate of active TB among RA patients receiving targeted therapy. METHODS: We analyzed data from two prospective cohort studies of RA patients who received biologic disease-modifying antirheumatic drugs (bDMARDs) or Janus kinase (JAK) inhibitor. We selected new starters of targeted therapy and classified them into three groups receiving tumor necrosis factor (TNF) inhibitor, non-TNF inhibitor, and JAK inhibitor, respectively. We then compared LTBI prevalence, treatments, and active TB incidence during first-line therapy in each group. RESULTS: A total of 765 RA patients (574 TNF inhibitor users, 132 non-TNF inhibitor users, and 59 JAK inhibitor users) were included in this study. Observation periods were 1,255.2 person-years (PYs), 264.7 PYs, and 53.3 PYs, respectively. All 765 patients underwent LTBI screening, and the positivity rate was 26.5% (n = 203). Of the 203 LTBI-positive patients, 189 (93.1%) received treatment. Only one patient, who was in the TNF inhibitor group, and was negative for the interferon gamma release assay (IGRA), did not receive LTBI treatment and developed active TB during follow-up. CONCLUSION: Although the prevalence of LTBI in RA patients who started targeted therapy was slightly elevated, the Korean guidelines specifying LTBI screening and treatment were effective in preventing latent TB from becoming active.