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Table 1 Characteristics of study population

From: Line blot immunoassays in idiopathic inflammatory myopathies: retrospective review of diagnostic accuracy and factors predicting true positive results

Number of patients
 Total342
 Mean age in years (SD)54 (14)
 Female gender222 (65%)
Pre-test working diagnosis
 Suspected IIM92 (26.9%)
 CTDs without IIM137 (40.1%)
 Myopathic syndromes with low likelihood of IIM113 (33.0%)
Final diagnosis and subtype
 IIM67 (19.6%)
 Overlap myositis21
 Dermatomyositis12
 Polymyositis11
 Antisynthetase syndrome7
 Amyopathic dermatomyositis7
 Inclusion body myositis5
 Immune mediated necrotizing myopathy4
 CTD without IIM120 (35.1%)
 Systemic sclerosis91
 Undifferentiated CTD10
 Systemic lupus erythematosus7
 Inflammatory arthritis6
 Overlap CTD4
 Sjogrens syndrome2
 Non-IIM/CTD155 (45.3%)
 Other rheumatologic diagnoses45
 Other neurologic diagnoses12
 Genetic myopathy11
 Endocrinologic myopathy5
 Idiopathic pulmonary fibrosis3
 Post-viral myopathy3
 Traumatic myopathy3
 Familial amyloidosis1
 Orbital myositis1
 Malignancy1
 Unclear70
  1. SD standard deviation, IIM idiopathic inflammatory myopathy, CTD connective tissue disease