(221) Incidence of Active Tuberculosis According to Latent Tuberculosis Infection Treatment Before Targeted Therapy in Patients with Rheumatoid Arthritis

Publication Number: 554

Background: Targeted therapies including tumor necrosis factor inhibitors (TNFi) and Janus kinase inhibitors (JAKi) are increasingly used for treatment of rheumatoid arthritis (RA). Preventive treatment for latent tuberculosis infection (LTBI) is being recommended for patients with RA who are receiving targeted therapy. There have been few studies on the incidence of active tuberculosis according to LTBI treatment before targeted therapy in patients with RA in Korea.

Objectives: The study aimed to estimate the incidence of tuberculosis (TB) following LTBI treatment before targeted therapy in patients with rheumatoid arthritis (RA).

Methods: We conducted a population-based cohort study of patients with RA who were prescribed their first JAKi or TNFi using the South Korea's nationwide healthcare database between 2015 and 2018. Patients were followed up from initiation of JAKi or TNFi until the incidence of active TB, death, or end of study period. To examine the association between LTBI treatment and active tuberculosis, we estimated the adjusted hazard ratio (aHR) and 95% confidence interval (CI) using Cox proportional hazards regression adjusting for age, sex, comorbidities, and medications.

Results: We included 3,382 patients within the study cohort, of which 596 were JAKi users and 2,786 were TNFi users. No cases of tuberculosis developed in JAKi users, whereas 32 tuberculosis cases were observed in TNFi users [incidence rate: 0.39 per 100 person-years (PYs) (95% CI 0.28–0.55)]. The median follow-up was 1.81 years for JAKi and 2.94 years for TNFi users. The incidence of tuberculosis was 1.01 (95% CI 0.64–1.58) and 0.18 (95% CI 0.10–0.30) per 100 PYs in LTBI treatment and no-treatment groups, respectively. The aHR of active tuberculosis in LTBI treatment group, which means a positive test for treatment, compared to no-treatment group was 2.22 (95% CI 0.25–18.14).

Conclusions: Despite non-significance of active tuberculosis, it still occurred in TNFi users despite prior treatment for LTBI and not in JAKi users. Further studies with larger sample sizes and longer follow-up are needed to understand the association between JAKi and the incidence of active tuberculosis in patients with RA.