Risk of tuberculosis in patients treated with anti-tumor necrosis factor therapy: A nationwide study in South Korea, a country with an intermediate tuberculosis burden

Aim: The aim of this study was to investigate the incidence of tuberculosis (TB) following anti-tumor necrosis factor (TNF) therapy in an intermediate TB burden area and to compare the risk between drugs and diseases. Methods: The data were obtained from a nationwide database maintained by the Health Insurance Review and Assessment Service. The study population comprised of patients who were prescribed with TNF inhibitors from 2005 to 2009. TB cases were selected based on prescription of anti-TB medications. Results: Of 8421 patients in the study population, 1729 patients with latent TB prophylaxis were identified and 102 patients developed TB. The incidence of TB was 1017 per 100 000 person-years. When divided into four groups according to the main diagnosis and using an ankylosing spondylitis group as a reference, the incidence of TB was highest in patients with inflammatory bowel disease (IBD) (incidence rate ratio [IRR] 5.97, 95% confidence interval [CI] 3.34-10.66), followed by patients with rheumatoid arthritis (IRR 1.02, 95% CI 0.57-1.83) and those with psoriatic arthritis (IRR 1.00, 95% CI 0.14-7.30). Comparison between drugs showed a significantly lower incidence of TB in patients treated with etanercept (reference), highest incidence in those treated with infliximab (IRR 6.8, 95% CI 3.74-12.37) and an intermediate incidence in patients treated with adalimumab (IRR 3.45, 95% CI 1.82-6.55). Conclusions: The difference in TB risk between TNF inhibitors was similar with countries of low TB burden. This study suggests that particular attention is required for patients treated with TNF monoclonal antibodies.