Characteristics of the study subjects.
| Characteristics | DM, n = 91 | PM, n = 7 |
|---|---|---|
| Age at biopsy, yrs; median (Q1–Q3) | 48 (37–60) | 39 (35–53) |
| Age at onset, yrs; median (Q1–Q3) | 45 (34–58) | 38 (33–52) |
| Time from onset to biopsy, mos; median (Q1–Q3) | 10 (4–21) | 11 (1–15) |
| Sex, female, % (n) | 64 (58) | 86 (6) |
| Race, % (n) | ||
| White | 68 (62) | 71 (5) |
| Black | 15 (14) | 14 (1) |
| Other | 16 (15) | 14 (1) |
| Place of biopsy, % (n) | ||
| Quadriceps | 46 (42) | 57 (4) |
| Deltoid | 41 (37) | 29 (2) |
| Biceps | 9 (8) | 14 (1) |
| Unknown | 4 (4) |
DM: dermatomyositis; PM: polymyositis.