Table 1 Demographic and clinical features of PM/DM patients and healthy controls
| Â | PM/DM patients | Healthy controls |
|---|---|---|
Age of onset, mean ± SD (range) years | 50.6 ± 17.4 (21.5 to 75.0) | 51.4 ±9.4 (27 to 70) |
Number of females/number of males | 77/21 | 27/10 |
Number of PM patients/number of DM patients | 41/57 | NA |
Duration of disease, mean ± SD (range) years | 5.3 ± 7.6 (1.3 to 28.0) | NA |
Clinical features, number of patients affected (% of cohort) | Â | Â |
  Interstitial lung disease | 50 (51.0%) | NA |
  Oropharyngeal dysphagia | 35 (35.7%) | NA |
  Raynaud’s phenomenon | 20 (20.4%) | NA |
  Mechanic’s hands | 12 (12.2%) | NA |
  Arthritis | 45 (45.9%) | NA |
Anti-Jo-1-positive at time of blood sampling | 20 (20.4%) | NA |
Levels of creatine kinase at initial visit, mean ± SD | 1437.2 ± 1536.5 | NA |