Summary of the characteristics of the 4 patients with anti-HMGCR autoantibodies compared with the remainder of the JIIM cohort. Patients with anti-HMGCR were weaker, had more severe disease, and had dramatically higher CK levels throughout their disease course.
| Patient | Skin Rash | Sex | Age at Disease Onset, Yrs | Lowest CMAS, 0–53 | Highest PGA, 0–10 | CK at Onset, IU/l | CK at 6 Mos Postdiagnosis, IU/l | CK at 12 Mos Postdiagnosis, IU/l | Lowest CK, IU/l |
|---|---|---|---|---|---|---|---|---|---|
| 1 | No | Female | 4 | 28 | 4.8 | 12,180 | 1275 | 278 | 231 |
| 2 | Minimal | Female | 13 | 0 | 8.3 | 44,002 | 404 | 13,065 | 251 |
| 3 | No | Male | 11 | 36 | 3 | 19,000 | 4702 | 4038 | 1527 |
| 4 | Minimal | Female | 9 | 2 | 9.5 | 12,662 | 2004 | 4638 | 2241 |
| Median (IQR) for patients with anti-HMGCR | 10.6 (7.5–12.3) | 15 (1.8–30) | 6.6 (4.4–8.6) | 15,500 (12,000–25,250) | 1057 (1057–2679) | 4338 (3098–6744) | 889 (246–1705.5) | ||
| Median (IQR) for all 381 patients | 6.8 (3.9–10.1) | 40 (24–47.3) | 4 (2.2–7) | 225 (78–1191.5)a | 65 (41–106)b | 88 (60–114)c | 53 (37–82.5) | ||
↵a Median for those with a raised CK 1039 (415.4–115.25).
↵b CK available between 4 and 8 months for 60 patients.
↵c CK available between 10 and 14 months for 48 patients. Anti-HMGCR: anti-HMG-CoA-reductase; JIIM: juvenile idiopathic inflammatory myositis; CK: creatine kinase; CMAS: Childhood Myositis Assessment Score, 0–53; PGA: physician’s global assessment visual analog score of disease activity, 0–10; IQR: interquartile range.