Background The incidence of nontuberculous mycobacteria (NTM) infection has been increasing worldwide in both general population and in immunocompromised patients, including rheumatoid arthritis (RA) patients. However, most of previous studies focused on clinical features of NTM infection during treatment with anti-tumor necrosis factor (TNF) or were conducted in western countries, where NTM infection is more common than tuberculosis (TB) infection.

Objectives The aims of our study were to identify the incidence and clinical characteristics of NTM infection in RA patients who live in the TB endemic area.

Methods We performed a retrospective analysis of cases with NTM infection in the RA registry at a tertiary referral center from January 1995 to December 2013. The clinical features of the NTM cases were compared to those of 52 patients with TB infection.

Results Among 1,397 patients with RA, NTM infection was newly developed in 26 (1.86%) patients and the incidence of NTM infection was 164.8 per 100,000 patient-years. The mycobacterium avium complex was the most frequent isolate (76.9%). None of the NTM infections had extrapulmonary involvement, which was rather common in TB infection (26.9%) (Table). Patients with NTM infection were older, received higher cumulative doses of corticosteroid, had higher rates of history of TB infection, and had higher incidence of concomitant interstitial lung disease (ILD) than cases with TB infection.

Conclusions In South Korea, NTM infection is not rare in RA patients. Physicians should be cautious about NTM infection in patients with history of TB infection or concomitant ILD, even in endemic areas of TB.

Disclosure of Interest None declared