Table 1.
Baseline characteristics of 19 included patients in the analysis
| Characteristic | Patients (n = 19) | DM (n = 8) | IMNM (n = 6) | NM/OM (n = 4) | ASS (n = 1) |
|---|---|---|---|---|---|
| Age at onset, median (IQR), years | 59 (37–69) | 44 (31–61) | 67 (62–69) | 60 (35–77) | 53 |
| Females, n (%) | 12 (63) | 5 (63) | 3 (50) | 3 (75) | 1 |
| European/Caucasian ancestry, n (%) | 13 (68) | 6 (75) | 4 (67) | 2 (50) | 1 |
| Disease duration, median (IQR), months | 5 (3–6) | 5 (3–6) | 5 (3–7) | 6 (4–8) | 4 |
| Dysphagia, n (%) | 14 (74) | 6 (75) | 4 (67) | 3 (75) | 1 |
| Extramuscular disease activity, n (%) | |||||
| Skin | 11 (58) | 8 (100) | 1 (17) | 1 (25) | 1 |
| Arthritis | 7 (37) | 2 (25) | 2 (33) | 2 (50) | 1 |
| Raynaud | 3 (16) | 1 (13) | 0 (0) | 1 (25) | 1 |
| Cardiaca | 3 (16) | 0 (0) | 2 (33) | 1 (25) | 0 |
| Pulmonaryb | 2 (11) | 0 (0) | 0 (0) | 2 (50) | 0 |
| Other, i.e. subcutaneous oedema | 13 (68) | 8 (100) | 3 (50) | 1 (25) | 1 |
| Connective tissue disorder, n (%) | 3 (16) | 0 | 1 | 2 | 0 |
| Cancer, n (%) | 0 (0) | 0 | 0 | 0 | 0 |
| Myositis-specific antibodies and myositis-associated antibodies, n (%) | |||||
| Anti-HMGCR+ | 3 (16) | 3 (50) | |||
| Anti-NXP2+ | 3 (16) | 3 (38%) | |||
| Anti-Jo1+ | 1 (5) | 1 | |||
| Anti-MDA5+ | 1 (5) | 1 (13) | |||
| Anti-SRP+ | 1 (5) | 1 (17) | |||
| Anti-TIF1γ+ | 1 (5) | 1 (13) | |||
| Seronegative | 3 (38) | 1 (17) | 3 (75) | ||
| Myositis-associated antibodies only | 2 (11) | 1 (17) | 1 (25) | ||
| Myositis-specific antibodies | 0 (0) | ||||
| Absent myositis-specific antibodies or myositis-associated antibodies | 7 (37) |
a
Cardiac extramuscular disease activity consisted of peri/myocarditis as diagnosed by the treating cardiologist based on cardiac magnetic resonance imaging. bPulmonary extramuscular disease activity consisted of interstitial lung disease as confirmed by high-resolution chest computer tomography. ASS: anti-synthetase syndrome; IMNM: immune-mediated necrotizing myopathy; IQR: interquartile range; NM/OM: non-specific/overlap myositis.