Table 1. Baseline characteristics of patients who were newly diagnosed with pulmonary NTM disease (n = 225).
| RA patients (n = 34) | Non-RA patients (n = 191) | p* | |
|---|---|---|---|
| Age, years, mean (95% CI) | 70.6 (67.1–74.2) | 70.7 (69.1–72.3) | 0.98 |
| ≥80, number (%) | 8 (23.5) | 46 (24.1) | 1.00 |
| ≥70 and <80, number (%) | 12 (35.3) | 57 (29.8) | 0.55 |
| <70, number (%) | 14 (41.2) | 88 (46.1) | 0.71 |
| Male, number (%) | 4 (11.8) | 62 (32.5) | 0.014 |
| RA duration, years, mean (95% CI) | 11.6 (7.7–15.5) | – | – |
| Steinbrocker’s stages III/IV, number (%) | 23 (67.6) | – | – |
| RA therapies†, before/after diagnosis, number (%) | 34 (100) / 34 (100) | – | – |
| MTX therapy | 10 (29.4) / 8 (23.5) | – | – |
| csDMARD (except MTX) therapy | 5 (14.7) / 8 (23.5) | – | – |
| bDMARD therapy (with or without MTX) | 11 (32.4) / 8 (23.5) | – | – |
| tsDMARD therapy (with or without MTX) | 1 (2.9) / 1 (2.9) | – | – |
| No DMARD use (oral steroids and/or NSAIDs) | 7 (20.6) / 9 (26.5) | – | – |
| Comorbidity, number (%) | |||
| Type 2 diabetes | 4 (11.8) | 24 (12.6) | 1.00 |
| Malignancy | 1 (2.9) | 26 (13.6) | 0.090 |
| Interstitial lung disease | 4 (11.8) | 15 (7.9) | 0.50 |
| Tuberculosis history, number (%) | 1 (2.9) | 9 (4.7) | 1.00 |
| Serum albumin, g/dl, mean (95% CI) | 3.6 (3.4–3.8) | 3.8 (3.7–3.8) | 0.19 |
| <3.0 | 4 (11.8) | 20 (10.5) | 0.77 |
| ≥3.0 and <4.0 | 21 (61.8) | 88 (46.1) | 0.10 |
| ≥4.0 | 9 (26.5) | 83 (43.5) | 0.09 |
| Lymphocyte count, /mm3, mean (95% CI) | 1195 (1047–1343) | 1394 (1320–1468) | 0.036 |
| <800 | 7 (20.6) | 21 (11.0) | 0.15 |
| ≥800 and <1000 | 5 (14.7) | 20 (10.5) | 0.55 |
| ≥1000 | 22 (64.7) | 150 (78.5) | 0.12 |
| Causative NTM species, number (%) | |||
| M. avium | 13 (38.2) | 46 (24.1) | 0.093 |
| M. intracellulare | 17 (50) | 128 (67.0) | 0.079 |
| M. abscessus complex | 4 (11.8) | 11 (5.8) | 0.25 |
| Other species‡ | 0 | 6 (3.1) | 0.60 |
| HRCT patterns of NTM disease, number (%) | |||
| Cavitary NB form | 10 (29.4) | 54 (28.3) | 1.00 |
| Non-cavitary NB form | 15 (44.1) | 82 (42.9) | 1.00 |
| Fibrocavitary form | 1 (2.9) | 26 (13.6) | 0.090 |
| Unclassifiable form | 8 (23.5) | 29 (15.2) | 0.22 |
| Presence of abnormal HRCT findings, number (%) | |||
| Cavitary lesion | 11 (32.4) | 80 (41.9) | 0.35 |
| Tree-in-bud sign | 18 (53.0) | 110 (57.6) | 0.71 |
| Consolidation | 15 (44.1) | 77 (40.3) | 0.71 |
| Nodules | 32 (94.1) | 179 (93.7) | 1.00 |
| Bronchiectasis/bronchiolectasis | 25 (73.5) | 159 (83.2) | 0.23 |
| Completion rate of anti-NTM therapy§, number (%) | 15 (44.1) | 87 (45.5) | 1.00 |
Data were obtained at the time of pulmonary NTM disease diagnosis.
*Comparisons of baseline characteristics between the RA and non-RA groups were performed using the chi-square test or Fisher’s exact probability test for categorial variables and by the independent-measures t-test for continuous variables.
†RA therapies represent those that patients were receiving when pulmonary NTM was first suspected (before diagnosis) and those that patients decided to continue or restart at the time of pulmonary NTM disease diagnosis (after diagnosis). bDMARDs included etanercept, infliximab, adalimumab, abatacept, and tocilizumab. csDMARDs included tacrolimus and salazosulfapyridine. tsDMARD was tofacitinib.
‡Other species included M. gordonae (n = 3), M. fortuitum (n = 2), and M. szulgai (n = 1).
§Treatment completion rate was defined as the number (%) of participants who had continued anti-NTM therapy until the primary treatment endpoint (culture-negative sputum for 12 months). This value was determined during follow-up.
RA, rheumatoid arthritis; MTX, methotrexate; DMARD, disease-modifying antirheumatic drug; csDMARD, conventional synthetic DMARD; bDMARD, biological DMARD; tsDMARD, targeted synthetic DMARD; NSAIDs, non-steroidal anti-inflammatory drugs; NTM, nontuberculous mycobacteria; NB form, nodular/bronchiectatic form; HRCT, high-resolution computed tomography.