Patient demographics and clinical features at time of biopsy
| Quadriceps (n=33) | Biceps (n=22) | p Value | |||
|---|---|---|---|---|---|
| Patient characteristic/clinical features | |||||
| Age at biopsy (years), median (IQR) | 6.2 (3.3, 10) | 7.5 (6.0, 9.3) | 0.37 | ||
| Age at onset (years), median (IQR) | 5.7 (3.3, 9.5) | 7.1 (5.7, 9.1) | 0.31 | ||
| Gender, female, number (%) | 21 (64) | 17 (77) | 0.36 | ||
| Time between symptoms onset to biopsy (months), median (IQR) | 3.0 (2.0, 6.5) | 2.5 (1.9, 5.4) | 0.17 | ||
| Strength of knee extensors by MMT,* n (%) | score | 2 | 5 (21) | 4 (18) | |
| 3 | 8 (33) | 8 (36) | 0.238 | ||
| 4 | 7 (29) | 10 (46) | |||
| 5 | 4 (17) | 0 (0) | |||
| Strength of elbow flexion by MMT,* n (%) | score | 2 | 2 (9) | 4 (18) | |
| 3 | 10 (43) | 8 (36) | 0.273 | ||
| 4 | 6 (26) | 9 (41) | |||
| 5 | 5 (22) | 1 (5) | |||
| CMAS,† median (IQR) | 23.5 (13.3–36.8) | N/A | N/A | ||
| PGA,‡ median (IQR) | 5.9 (3.5–7.2) | N/A | N/A | ||
| Calcinosis, n (%) | 0 (0) | 6 (27) | 0.002 | ||
| Skin ulceration,** n (%) | 4 (13) | 3 (14) | 0.903 | ||
| Lung involvement,** n (%) | 8 (25) | 5 (23) | 0.848 | ||
| Cardiac involvement,** n (%) | 0 (0) | 2 (9) | 0.161 | ||
| Gastrointestinal involvement,** n (%) | 10 (31) | 9 (41) | 0.465 | ||
*MMT, manual muscle testing using the Medical Research Council scale, possible scores from 0 to 5.8
**Data available on 32 of the 33 cases.
†CMAS, Childhood Myositis Assessment Score, range 0–53.
‡PGA, physicians global assessment, range 0.0–10.0.