Rheumatoid Arthritis Increases the Risk of Nontuberculosis Mycobacterial Disease and Active Pulmonary Tuberculosis

Background: Few studies have examined the association of rheumatoid arthritis (RA) with nontuberculosis mycobacterium (NTM) disease and pulmonary tuberculosis (PTB). Methods: We identified 29 131 patients with RA from the catastrophic illness registry who were diagnosed from 1998-2008; 116 524 patients without RA from inpatient data files were randomly frequency matched according to sex, age, and index year and used as a comparison group. Both groups were followed-up until the end of 2010 to measure the incidence of NTM disease and active PTB. We analyzed the risk of NTM disease and active PTB using the Cox proportional hazards regression models, controlling for sex, age, and Charlson comorbidity index (CCI). Results: The incidence of NTM disease was 4.22 times greater in the RA group than in the non-RA group (1.91 vs 0.45 per 10,000 person-years). The incidence of PTB was 2.99 times greater in the RA group than in the non-RA group (25.3 vs 8.46 per 10,000 person-years). After adjusting for age, sex, and CCI, the adjusted hazard ratios (HRs) of NTM disease and active PTB for the RA group were 4.17 (95% CI = 2.61-6.65) and 2.87 (95% CI = 2.55-3.23), respectively, compared with the non-RA group. In the first 2 years of follow-up, the RA group yielded corresponding adjusted HRs of 4.98 and 3.39 compared with the non-RA group. The follow-up time-specific RA group to the non-RA group HR of both the NTM disease and active PTB varied. Conclusion: This study can serve as a reference for clinical physicians to increase awareness regarding the detection of NTM disease and active PTB in RA patients among the any stage of the clinical course even without CCI.