Comparison of developing tuberculosis following tumor necrosis factor inhibition and interleukin-6 inhibition in patients with rheumatoid arthritis: a nationwide observational study in South Korea, 2013–2018

Background: Tumor necrosis factor (TNF) inhibitors increase the risk of tuberculosis (TB) in patients with rheumatoid arthritis (RA). This study compared the incidence of TB after treatment with TNF inhibitors and tocilizumab in patients with RA, separately in those who were treated for latent tuberculosis infection (LTBI) and those without evidence of LTBI. Methods: This study included patients with RA who initiated TNF inhibitors and tocilizumab between December 2013 and August 2018. Patient data were collected from the nationwide database of the Health Insurance Review and Assessment service in South Korea. The incidence of TB was compared among different biologic drugs in patients with or without LTBI treatment. Results: Of 4736 patients, 1168 were treated for LTBI and 48 developed TB (554.9 per 100,000 person-years). When compared based on etanercept, infliximab showed a higher risk of TB (adjusted incidence rate ratio 2.71, 95% confidence interval 1.05–7.01), especially in patients without evidence of LTBI. Other TNF inhibitors and tocilizumab showed a comparable incidence of TB, regardless of treatment for LTBI. There was no significant difference in TB incidence after biologic therapy between patients with and without LTBI treatment (627.9/100,000 vs. 529.5/100,000 person-years). In patients treated for LTBI, no differential risk of TB was observed among biologic drugs. Conclusions: The incidence of TB was not significantly different among biologic drugs in the current era, except for infliximab in patients who were not treated for LTBI. Treatment of LTBI might alleviate the drug-specific risk of TB in patients with RA.