Demographic and clinical information of cases in the EuroMyositis Registry
| Dermatomyositis | Polymyositis | Antisynthetase syndrome | Connective tissue disease-overlap myositis | Inclusion body myositis | Immune- mediated necrotising myopathy | Juvenile dermato-myositis | Total n (%) | |
| Number of cases—n (% of total) | 949 (31) | 813 (27) | 512 (17) | 358 (12)* | 240 (8) | 105 (3) | 90 (3) | 3067 (100) |
| Gender—% male | % female (n=3002) | 30 | 70 | 29 | 71 | 31 | 69 | 21 | 79 | 61 | 39 | 36 | 64 | 32 | 68 | 944 (32) male 2058 (69) female |
| Ethnicity—% per diagnosis (n=2681) | ||||||||
| Caucasian | 75 | 74 | 86 | 86 | 96 | 93 | 76 | 2155 (80) |
| Asian/Oriental | 15 | 20 | 6 | 10 | 3 | 4 | 12 | 332 (12) |
| Hispanic | 7 | 4 | 1 | 1 | 0 | 2 | 9 | 98 (4) |
| Black African | 3 | 3 | 5 | 3 | 1 | 1 | 3 | 81 (3) |
| Other | 0 | 0 | 2 | 1 | 0 | 0 | 0 | 15 (1) |
| Mean age in years at disease onset (SD) (n=2427) | 49 (15) | 50 (15) | 48 (15) | 45 (15) | 61 (10) | 56 (15) | 10 (5) | 49 years (SD 16) |
| Mean age in years at diagnosis (SD) (n=2000) | 51 (15) | 52 (15) | 49 (15) | 48 (15) | 65 (10) | 57 (15) | 10 (5) | 51 years (SD 17) |
| Median interval in months between disease onset and diagnosis (IQR) (n=1668†) | 5 (2–11) | 8 (3–19) | 7 (3–13) | 11 (4–24) | 41 (24–72) | 7 (4–12) | 8 (3–22) | 8 months (IQR 3–22) |
| Clinical features—% per diagnosis | ||||||||
| Myopathic muscle weakness (n=2521) | 92 | 98 | 90 | 94 | 92 | 94 | 91 | 2352 (93) |
| Rash‡ (n=1993) | 100 | 0 | 44 | 32 | 0 | 0 | 100 | 1077 (54) |
| Raynaud’s phenomenon (n=1903) | 25 | 28 | 51 | 60 | 8 | 20 | 18 | 643 (34) |
| Periungal erythema (n=1305) | 52 | 6 | 32 | 33 | 2 | 15 | 37 | 434 (33) |
| Arthritis (n=2288) | 20 | 20 | 50 | 42 | 8 | 10 | 23 | 632 (28) |
| Mechanics’ hands (n=1958) | 22 | 8 | 38 | 16 | 1 | 4 | 7 | 363 (19) |
| Calcinosis (n=1314) | 7 | 1 | 3 | 10 | 1 | 0 | 44 | 78 (6) |
| Ulceration (n=1152) | 13 | 2 | 3 | 10 | 0 | 2 | 5 | 79 (7) |
Disease onset is defined as the date of onset of the first symptoms of idiopathic inflammatory myopathy.
*Associated connective tissue diseases: systemic sclerosis (39%, 141/358), Sjögrens syndrome (15%, 54/358), mixed connective tissue disease (15%, 52/358), rheumatoid arthritis (9%, 32/358), systemic lupus erythematosus (9%, 32/358), other (13%, 47/358).
†Excludes 281 cases where diagnosis and onset are recorded with the same date.
‡Includes Gottron’s papules/sign heliotrope, rash, ‘V’ sign, shawl sign and erythroderma.