Table 2. Clinical characteristics of patients with DM, stratified by autoantibody status.
| Demographic and clinical findings | Anti-MDA5 positive* | Anti-ARS positive* | Anti-MDA5/anti-ARS negative | P† |
|---|---|---|---|---|
| (n = 55) | (n = 31) | (n = 86) | ||
| Age at onset, mean ± SD | 50.8 ± 14.3 | 52.9 ± 15.7 | 58.4 ± 17.3 | 0.01 |
| Female, % | 72.7 | 83.9 | 66.3 | 0.17 |
| DM subgroup | ||||
| Classic DM, % | 18.2 | 90.3 | 76.7 | < 0.0001 |
| CADM, % | 81.8 | 9.7 | 23.3 | < 0.0001 |
| ILD overall, % | 90.9 | 80.6 | 27.9 | < 0.0001 |
| ILD type | ||||
| RP-ILD, % | 83.6 | 25.8 | 10.5 | < 0.0001 |
| Chronic ILD, % | 7.3 | 54.8 | 17.4 | < 0.0001 |
| Gottron’s sign, % | 87.3 | 67.7 | 79.1 | 0.10 |
| Heliotrope rash, % | 49.1 | 25.8 | 55.8 | 0.02 |
| Arthritis, % | 65.5 | 48.4 | 22.1 | < 0.0001 |
| Fever, % | 61.8 | 35.5 | 30.2 | 0.0008 |
| Malignancy, % | 5.5 | 9.7 | 34.9 | < 0.0001 |
*Two patients who were positive for both anti-MDA5 and anti-ARS by ELISA, but were negative for anti-ARS by IP assay were included in the anti-MDA5-positive group.
†Statistical analysis was performed by chi-square tests on a 2 × 3 table.