Table 4.

Muscle biopsy features, treatments, and duration of disease in anti-Jo1 positive patients diagnosed with DM and PM.

	DM N (%)	PM N (%)	p-value
Perivascular inflammation	9 (69.2%)	6 (85.7%)	0.6
Perifascicular atrophy	8 (61.5%)	4 (57.1%)	1
Primary inflammation	4 (30.8%)	4 (57.1%)	0.4
Mitochondrial dysfunction*	2 (25.0%)	2 (16.7%)	1
Necrotizing myopathy	2 (15.4%)	0 (0.0%)	0.5
Immunosuppression prior to biopsy	8 (61.5%)	3 (42.9%)	0.6
On immunosuppression during biopsy	6 (54.4%)	3 (42.9%)	1
Corticosteroids during biopsy	4 (30.8%)	2 (28.6%)	1
Days from the onset of symptoms to the biopsy (median [Q1–Q3])	725 (531–874)	374 (37–435)	0.1

Fisheŕs exact test and Wilcoxon rank-sum test p-values are shown for the categorical and quantitative variables respectively.