Table 1. Characteristics of the patients with and without RA.
| Characteristic | RA (n = 71) |
Non-RA (n = 1478) |
p value |
|---|---|---|---|
| Age (years) | 71.0 ± 8.9a | 66.9 ± 17.1 | <0.001 |
| ≥65 years | 53 (74.6) | 956 (64.7) | 0.097 |
| Female sex | 39 (54.9) | 451 (30.5) | <0.001 |
| Smokers | 29 (40.8) | 918 (62.1) | <0.001 |
| HCAP | 23 (32.4) | 484 (32.7) | 1.000 |
| Comorbidity | |||
| None | 10 (14.1) | 339 (22.9) | 0.008 |
| Pulmonary disease | 51 (71.8) | 772 (52.2) | 0.001 |
| COPD | 12 (16.9) | 324 (21.9) | 0.377 |
| Asthma | 1 (1.4) | 149 (10.1) | 0.012 |
| Bronchiectasis | 9 (12.7) | 91 (6.2) | 0.043 |
| Nontuberculous mycobacteriosis | 10 (14.1) | 65 (4.4) | 0.002 |
| Old pulmonary tuberculosis | 3 (4.2) | 105 (7.1) | 0.477 |
| Chronic pulmonary aspergillosis | 1 (1.4) | 25 (1.7) | 1.000 |
| Interstitial pneumonia | 21 (29.6) | 85 (5.8) | <0.001 |
| Post lung cancer operation | 1 (1.4) | 57 (3.9) | 0.517 |
| Other pulmonary diseaseb | 12 (16.9) | 56 (3.8) | <0.001 |
| Systemic disease | 33 (46.5) | 655 (44.3) | 0.716 |
| Steroid or immunosuppressant | 46 (64.8) | 87 (5.9) | <0.001 |
| Severe | 7 (9.9) | 218 (14.7) | 0.303 |
| Mortality | 8 (11.3) | 74 (5.0) | 0.050 |
RA, rheumatoid arthritis; HCAP, healthcare-associated pneumonia; COPD, chronic obstructive pulmonary disease.
aData are presented as means ± standard deviation or n (%).
b“Other pulmonary disease” includes the following incidences of each disease: bronchiolitis (n = 6), chronic eosinophilic pneumonia (n = 2), and others (n = 5) in the RA patients, and pneumoconiosis (n = 13), sarcoidosis (n = 9), chronic empyema (n = 8), pulmonary thromboembolism (n = 6), asbestos pleuritis (n = 4), pulmonary hypertension, alveolar proteinosis (n = 3 each), and others (n = 10) in the non-RA patients. Some patients had more than one comorbidity.