Table 1 Characteristics of study population
Number of patients | |
|---|---|
Total | 342 |
Mean age in years (SD) | 54 (14) |
Female gender | 222 (65%) |
Pre-test working diagnosis | |
Suspected IIM | 92 (26.9%) |
CTDs without IIM | 137 (40.1%) |
Myopathic syndromes with low likelihood of IIM | 113 (33.0%) |
Final diagnosis and subtype | |
IIM | 67 (19.6%) |
Overlap myositis | 21 |
Dermatomyositis | 12 |
Polymyositis | 11 |
Antisynthetase syndrome | 7 |
Amyopathic dermatomyositis | 7 |
Inclusion body myositis | 5 |
Immune mediated necrotizing myopathy | 4 |
CTD without IIM | 120 (35.1%) |
Systemic sclerosis | 91 |
Undifferentiated CTD | 10 |
Systemic lupus erythematosus | 7 |
Inflammatory arthritis | 6 |
Overlap CTD | 4 |
Sjogrens syndrome | 2 |
Non-IIM/CTD | 155 (45.3%) |
Other rheumatologic diagnoses | 45 |
Other neurologic diagnoses | 12 |
Genetic myopathy | 11 |
Endocrinologic myopathy | 5 |
Idiopathic pulmonary fibrosis | 3 |
Post-viral myopathy | 3 |
Traumatic myopathy | 3 |
Familial amyloidosis | 1 |
Orbital myositis | 1 |
Malignancy | 1 |
Unclear | 70 |