Rheumatoid Arthritis and Risk of Nontuberculous Mycobacterial Pulmonary Disease: A Nationwide Longitudinal Cohort Study

Background In this study, we aimed to evaluate the risk of incident nontuberculous mycobacteria pulmonary disease (NTM-PD) in subjects with rheumatoid arthritis (RA) versus age- and sex-matched controls, while focusing on the impact of RA serologic status on this association. Methods From the Korean National Health Insurance Service data from 2010 to 2017, we identified 60,315 participants aged ≥ 20 years with RA and 301,575 without RA who were age- and sex-matched 1:5. The participants were followed up from 1 year after RA diagnosis (or the corresponding index date for matched controls) to the date of NTM-PD diagnosis, censored date, or December 31, 2019, whichever occurred first. Results During a median 4.5 (interquartile range, 2.6–6.4)-year follow-up, NTM-PD occurred in 0.23% and 0.06% of the RA and matched cohort (incidence: 0.54 and 0.14 per 1,000 person-years), respectively. Compared to controls, participants with RA had a 3.11-fold (95% confidence interval [CI]: 2.50–3.88) higher risk of NTM-PD. In the subgroup analysis stratified by seropositivity, seropositive patients with RA had a 3.77-fold (95% CI: 3.00–4.73) higher risk of NTM-PD than controls whereas participants with seronegative RA did not have a significantly higher risk (adjusted hazard ratio: 1.18, 95% CI: 0.68–2.04). Stratified analyses showed a more prominent association of RA with NTM-PD in males, alcohol drinkers, and obese individuals ( p  < 0.05). Conclusion The risk of incident NTM-PD was approximately 3-fold higher in participants with RA than in matched controls, although the association was significant only for patients with seropositive RA.