Table 2.
Demographic and phenotypic characteristics of patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and RA without ILD according to MUC5B gene mutation status.
| RA-ILD group | RA group | |||||
|---|---|---|---|---|---|---|
| MT MUC5B (N=19) | WT MUC5B (N=26) | p-Value | MT MUC5B (N=9) | WT MUC5B (N=42) | p-Value | |
| Female gender. No./Total No. (%) | 12/19 (63.2) | 15/26 (57.7) | 0.77 | 4/9 (44.4) | 26/42 (61.9) | 0.46 |
| Age at inclusion (years) | 62.1±8.5 | 57.7±8.6 | 0.11 | 40.5±6.4 | 49.2±13.4 | 0.38 |
| Age at RA onset (years) | 50.8±11.9 | 52.5±12.5 | 0.74 | 37.0±5.7 | 41.4±12.3 | 0.63 |
| RA duration (years) | 7.1±5.1 | 7.1±7.0 | 0.98 | 3.5±0.7 | 4.6±4.4 | 0.37 |
| Age at onset of ILD (years) | 57.6±6.9 | 55.2±8.4 | 0.40 | |||
| ILD duration (years) | 3.0±1.6 | 1.9±1.4 | 0.03* | |||
| Ever smoker. No./Total No. (%) | 3/19 (15.8) | 5/26 (19.2) | 0.99 | 2/9 (22.2) | 14/42 (38.1) | 0.70 |
| Erosive disease. No./Total No. (%) | 12/19 (63.2) | 19/2 (73.1) | 0.53 | 4/9 (44.4) | 31/42 (73.8) | 0.12 |
| Laboratory indicators | ||||||
| ACPA titer | 944.8±1158.0 | 1321.8±1105.8 | 0.38 | 1700.0±2121.3 | 560.9±729.8 | 0.58 |
| Rheumatoid factor titer | 145.2±114.3 | 568.9±1011.7 | 0.13 | 121.4±58.5 | 89.8±114.8 | 0.71 |
| ESR | 29.8±15.2 | 40.6±32.3 | 0.24 | 28.4±19.1 | 22.9±16.6 | 0.68 |
| Pattern on HRCT | ||||||
| NSIP or possible NSIP. No./Total No. (%) | 2/19 (10.5) | 4/26 (15.4) | 0.99 | |||
| UIP or possible UIP. No./Total No. (%) | 12/19 (63.2) | 7/26 (26.9) | 0.01* | |||
| Pulmonary function | ||||||
| Forced vital capacity (% of predicted value) | 78.5±17.4 | 80.5±22.8 | 0.81 | |||
| DLCO (% of predicted value) | 59.2±13.2 | 58.2±14.2 | 0.86 | |||
| Total lung capacity (% of predicted value) | 80.8±21.5 | 78.6±17.8 | 0.79 | |||
| Acute exacerbation. No./Total No. (%) | 13/19 (68.4) | 12/26 (46.2) | 0.22 | |||
MT – mutant-type; WT – wild-type; ILD – interstitial lung disease; ACPA – anti-citrullinated protein antibody; ESR – erythrocyte sedimentation rate; NSIP – non-specific interstitial pneumonia; UIP – usual interstitial pneumonia; DLCO – diffusion capacity for carbon monoxide; HRCT – high-resolution computed tomography.