Prognostic factors and radiographic outcomes of nontuberculous mycobacterial lung disease in rheumatoid arthritis.

Objective. The aims of our study were to retrospectively review patients with rheumatoid arthritis (RA) with nontuberculous mycobacterial (NTM) lung disease, to assess the prognostic factors, and to analyze the time to disease deterioration according to the antirheumatic drugs received during the NTM lung disease followup period. Methods. We retrospectively analyzed medical records of 98 HIV-negative RA patients with NTM lung disease treated at our institution, and investigated potential risk factors of mortality with Cox regression analysis. Time to radiologic deterioration was evaluated if antirheumatic drugs were not changed during observational periods and computed tomography was performed once each year. Results. Mean patient age was 67.6 years, and median followup period was 4.4 years. NTM species included Mycobacterium avium complex (83.7%), M. kansasii (6.1%), M. gordonae (6.1%), and others (4.1%). Radiographic features included nodular/bronchiectatic (NB) disease (57.1%), fibrocavitary (FC) disease (14.3%), FC+NB disease (16.3%), and other types (12.2%). Initial management included observation in 74 (75.5%) patients. Negative prognostic factors of mortality were C-reactive protein (CRP) >= 1.0 mg/dl and radiographic features of FC, FC+NB, or other disease types. Median time to radiologic deterioration was 3.6 years. Erythrocyte sedimentation rate (ESR) > 50 mm/h was a negative prognostic factor of radiologic deterioration. Conclusion. The most frequent NTM species was M. avium complex. CRP and radiographic features were prognostic factors for all-cause mortality, and ESR was a prognostic factor of radiologic deterioration. Further studies are warranted focusing on time to disease deterioration according to antirheumatic drug received during NTM followup.