title: Rheumatoid arthritis increases the risk of nontuberculosis mycobacterial disease and active pulmonary tuberculosis.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Internal Medicine and Family Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan; Chia Nan University of Pharmacy and Science, Tainan, Taiwan; Meiho University, Pingtung, Taiwan.
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: Yeh
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan; College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Yu-Chiao
authors.initials: YC
authors.lastname: Wang
authors.affiliation: College of Medicine, China Medical University, Taichung, Taiwan; Graduate Institute of Clinical Medical Science, China Medical University College of Medicine, Taichung, Taiwan.
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.affiliation: Graduate Institute of Clinical Medical Science, China Medical University College of Medicine, Taichung, Taiwan; Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000453:epidemiology* / Q000276:immunology; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology* / Q000276:immunology