Table 3.

Significant associations with disease course in patients with juvenile idiopathic inflammatory myopathies from multinomial logistic regression analyses.

	p-value Likelihood ratio test	Multinomial odds ratio [95% confidence interval]
		Chronic vs. Monocyclic	Polycyclic vs. Monocyclic	Chronic vs. Polycyclic
Significant determinants from General analysis†		n=73	n=71	n=153
Any myositis-specific autoantibodies#	0.00002	4.2 [2.2–7.9]	2.8 [1.4–5.8]	NS
Any myositis-associated autoantibodies	0.003	4.8 [1.8–12.9]	3.5 [1.1–11.1]	NS
Any infections within six months of illness onset	0.002	2.5 [1.0–5.8]	4.7 [1.9–11.9]	NS
Overall clinical symptom score*	0.002	NS	0.02 [0.0–0.6]	146 [8–2526]
Significant determinants from Specific analysis‡		n=85	n=80	n=177
Anti-p155/140 autoantibodies	0.00008	3.9 [2.0–7.7]	2.3 [1.1–5.0]	NS
Severe illness onset	0.002	2.1 [1.2–3.8]	NS	2.6 [1.4–4.9]

^*Odds ratio: per 0.01 increase in overall clinical symptom score.

^†Removed from the model in General analysis in backward elimination: severe illness onset

^#Anti-MDA5 autoantibodies were not included in the variable “any myositis-specific autoantibodies” in the multinomial logistic regression analysis, as 54 patients’s sera were not tested for this autoantibody.

^‡Removed from the model in Specific analysis in backward elimination: photosensitivity, “V-sign” and/or “Shawl-sign” rashes, contractures, cuticular overgrowth, weight loss, distal weakness, anti-Ro autoantibodies, geoclimatic zone at illness onset, and gastrointestinal infection within six months of illness onset.

NS: not significant (i.e. p≥0.05).

Data was adjusted for the included variables (p<0.05) in each model.