Table 1.
Characteristics of enrolled subjects with ILDs and matched non-ILD controls
| Variable | Non-ILD (n=2020) | ILD (n=505) | P value |
| Basic data | |||
| Age, years | 59.4±14.0 | 60.1±14.7 | 0.30 |
| Gender, female | 1520 (75.2) | 380 (75.2) | 1.00 |
| Disease duration, years | 6.9±5.1 | 6.7±5.7 | 0.45 |
| CCI | 1.4±1.4 | 1.8±1.5 | <0.01 |
| CCI without pulmonary disease | 1.3±1.5 | 1.5±1.4 | 0.01 |
| COPD | 161 (8.0) | 126 (25.0) | <0.01 |
| Asthma | 25 (1.2) | 12 (2.4) | 0.06 |
| Urbanisation | |||
| Level 1 | 588 (29.1) | 165 (32.7) | 0.48 |
| Level 2 | 634 (31.4) | 152 (30.1) | |
| Level 3 | 317 (15.7) | 74 (14.7) | |
| Level 4 | 481 (23.8) | 114 (22.6) | |
| Payroll-related insured amount, New Taiwan Dollars | |||
| ≤15 840 | 615 (30.4) | 160 (31.7) | 0.94 |
| 15 841–20 100 | 393 (19.5) | 96 (19.0) | |
| 20 100–27 600 | 523 (25.9) | 126 (25.0) | |
| ≥27 600 | 489 (24.2) | 123 (24.4) | |
| Medication | |||
| csDMARDs | |||
| Methotrexate | 452 (22.4) | 154 (30.5) | <0.01 |
| Sulfasalazine | 369 (18.3) | 105 (20.8) | 0.19 |
| Leflunomide | 103 (5.1) | 44 (8.7) | <0.01 |
| Hydroxychloroquine | 1058 (52.4) | 308 (61.0) | <0.01 |
| Ciclosporin | 49 (2.4) | 28 (5.5) | <0.01 |
| Azathioprine | 191 (9.5) | 67 (13.3) | 0.01 |
| Cyclophosphamide | 31 (1.5) | 27 (5.3) | <0.01 |
| Mycophenolate mofetil | 20 (1.0) | 6 (1.2) | 0.69 |
| Glucocorticoid | 1284 (63.6) | 408 (80.8) | <0.01 |
| Prednisolone equivalent, mg/day* | 2.5±4.1 | 5.1±8.5 | <0.01 |
| bDMARDs | |||
| Anti-TNF | 95 (4.7) | 42 (8.3) | <0.01 |
| Etanercept | 57 (2.8) | 25 (5.0) | 0.02 |
| Adalimumab | 36 (1.8) | 18 (3.6) | 0.01 |
| Golimumab | 3 (0.1) | 0 (0.0) | 0.39 |
| Tocilizumab | 1 (0.05) | 2 (0.4) | 0.04 |
| Rituximab | 16 (0.8) | 10 (2.0) | 0.02 |
| Air pollutant levels | |||
| PM2.5 (µg/m3) | 3.1±0.7 | 3.0±0.6 | <0.01 |
| PM10 (µg/m3) | 5.4±1.2 | 5.1±1.1 | <0.01 |
| SO2 (ppb) | 0.4±0.1 | 0.3±0.1 | <0.01 |
| NO2 (ppb) | 1.8±0.6 | 1.8±0.5 | 0.71 |
| CO (ppm) | 0.5±0.2 | 0.6±0.2 | 0.42 |
| O3 (ppb) | 2.8±0.3 | 2.7±0.3 | <0.01 |
Data are presented as mean±SD and N (%).
*Prednisolone equivalent.
bDMARDs, biological disease-modifying antirheumatic drugs; CCI, Charlson Comorbidity Index; CO, carbon monoxide; COPD, chronic obstructive pulmonary disease; csDMARDs, conventional synthetic DMARDs; ILD, interstitial lung disease; MPA, mycophenolic acid; NO2, nitrogen dioxide; O3, ozone; PM10, particulate matter <10 μm; PM2.5, particulate matter <2.5 μm; SO2, sulphur dioxide; TNF, tumour necrosis factor.