To estimate the incidence of tuberculosis (TB) in rheumatoid arthritis (RA) patients treated with tumor necrotizing factor inhibitor (TNFI) and evaluate the safety of resuming biologic disease-modifying anti-rheumatic drugs (DMARDs) in patients who developed TB after anti-TNF treatment.
We conducted an inception cohort study of RA patients in the Korean Healthcare Claims Database who started TNFI as the first biologic DMARD between January 2009 and December 2013. The incidence rate (IR) of TB was estimated among total TNFI starters and a nested case-control analysis was performed to compare the characteristics of patients who developed TB and those did not. Patients diagnosed with relapsed TB after resuming biologic DMARDs were identified and their features were described.
We included 4638 RA patients who started TNFI, contributing 8542 PYs of follow-up. The IR of TB in TNFI users was 1.10 (CI: 0.86-1.34) per 100 PYs. After the initial 6 months, the IR was highest at 1.56 (CI: 1.02-2.10) and decreased gradually over time. Among the 81 patients who developed TB, 30 patients (37.0%) resumed biologic DMARDs with a mean interval of 3.3 months after TB development. Two cases of TB were detected among 30 patients with an observational period of 45.7 PY.
The IR of TB in RA patients who started TNFI was 1.10 per 100 PYs. This rate was highest during the first 6 months. Resumption of biologic DMARDs requires careful monitoring for TB relapse.