Table 4.

Summary of random survival forest analysis relating risk of death and clinical features^*

Illness Feature	Mean Relative Importance
Clinical subgroup (JDM vs. JPM/JCTM)	1.00
Illness severity at onset	0.33
Age at diagnosis	0.32
Weight loss	0.30
Delay to diagnosis	0.23
“Shawl sign” rash	0.08
Abdominal pain	0.07
Age at onset	0.06
Gottron’s papules	0.05
Anti-Ku Abs	0.00
Anti-Sm Abs	0.00
Anti-La Abs	0.00
Any aminoacyl tRNA synthetase Abs	0.00
Anti-alanyl-tRNA synthetase (anti-PL-12) Abs	0.00
Dysphagia	0.00
Interstitial lung disease	0.00
Abdominal perforation (first symptom)	0.00
Ever hospitalized	0.00
Gastroesophageal regurgitation	− 0.04
Raynaud’s phenomenon	−0.04
Dysphonia	− 0.19

Abbreviations. JDM = juvenile dermatomyositis; JPM = juvenile polymyositis; JCTM = juvenile myositis associated with an underlying connective tissue disease; Abs=autoantibodies.

^*Mean importance values for 10 runs are compared to the highest mean importance value. All features with P<0.10 in Cox regression are included.