Table 1:
Demographics and clinical features of 49 adult patients with juvenile idiopathic inflammatory myopathies
| Clinical Diagnosis, % | ||
| Juvenile dermatomyositis | 75.5 | |
| Juvenile polymyositis | 10.2 | |
| Juvenile connective tissue myositis (JCTM) | 14.3 | |
| Age, years, median [IQR] | 24.0 | [19.0-28.6] |
| Race, % | ||
| Caucasian | 59.2 | |
| African American | 11.1 | |
| Hispanic | 17.7 | |
| Othera | 12.0 | |
| Female sex, % | 81.6 | |
| Age at diagnosis, years, median [IQR] | 11.0 | [8.5-15.7] |
| Disease duration at cross-sectional evaluation, years, median [IQR] | 11.5 | [4.5-18.9] |
| Delay to diagnosis, months, median [IQR] | 6.0 | [2.3-13.7] |
| Any myositis specific autoantibodiesb, % | 67.5 | |
| Anti-p155/p140 (TIF-1) | 27.5 | |
| Anti-MJ (NXP2) | 22.5 | |
| Anti-Jo1 | 7.5 | |
| Anti-MDA5 | 5.0 | |
| Anti-SRP | 5.0 | |
| Any myositis associated autoantibodiesb, % | 40.0 | |
| Anti-Ro60 | 20.0 | |
| Anti-Ro52 | 17.1 | |
| Anti-U1-RNP | 12.5 | |
| Otherc | 7.5 | |
| Severity at onset Likert scale (0-4), median [IQR] | 1.0 | [1.0-2.0] |
| Disease Course, % | ||
| Chronic continuous | 63.3 | |
| Polycyclic | 30.6 | |
| Monocyclic | 6.1 | |
| Height percentile at cross-sectional evaluation | 30.7 | [10.0-60.1] |
| Current physician global activity score 10 cm VAS, median [IQR] | 1.6 | [1.0-3.7] |
| Current physician global damage score 10 cm VAS, median [IQR] | 3.0 | [2.0-4.4] |
| Current HAQ score, median [IQR] | 0.4 | [0.0-1.0] |
| Current MMT26 score, 0-260d, median [IQR] | 229.0 | [212.6-256.8] |
| ACR functional class, worst ever (1-4), median [IQR] | 4.0 | [3.0-4.0] |
| ACR functional class at cross-sectional evaluation (1-4), median [IQR] | 2.0 | [1.5-3.0] |
| Maximal number of medications ever used, median [IQR] | 5.0 | [3.0-8.0] |
| Prednisone ever used, % | 100 | |
| Methotrexate ever used, % | 86.0 | |
| IV methylprednisolone ever used, % | 60.5 | |
| IVIG ever used,% | 60.5 | |
| DMARDs ever usede, % | 59.1 | |
| Biologic therapy ever usedf, % | 31.8 | |
| Cyclophosphamide ever used, % | 17.5 | |
| Number of medications at cross-sectional evaluation, median [IQR] | 3.0 | [1.0-4.0] |
| Prednisone at cross-sectional evaluation, % | 56.5 | |
| Methotrexate at cross-sectional evaluation, % | 39.1 | |
| IVIG at cross-sectional evaluation, % | 38.6 | |
| DMARDs at cross-sectional evaluation, % | 32.6 | |
| IV methylprednisolone at cross-sectional evaluation, % | 15.6 | |
| Biologic therapy at cross-sectional evaluation, % | 9.1 | |
| Cyclophosphamide at cross-sectional evaluation, % | 2.3 |
Race was self-reported. “Other” includes Indian (n = 1), Yemeni (n = 1), Korean (n = 1), and Not Reported (n = 4).
All autoantibodies were tested in 40 patients, except Anti-Ro52, which was tested in 35 patients.
Other MAAs included anti-PM/Scl (2.5%), anti-La (2.5%), and anti-Smith (2.5%). 10%> of patients had multiple MAAs. The MSA anti-Mi-2 was not present in this cohort.
MMT26 scores were available in 47 patients
DMARDS included azathioprine (n = 14), cyclosporine (n = 12), mycophenolate mofetil (n = 13), and tacrolimus (n = 2).
Biologics included abatacept (n= 2), adalimumab (n = 1), anakinra (n = 1), etanercept (n = 3), infliximab (n = 2), and rituximab (n = 11).
Abbreviations: ACR: American College of Rheumatology; DMARDs: Disease-Modifying Anti-Rheumatic Drugs; HAQ: Health Assessment Questionnaire; IQR: interquartile range; IV: intravenous; IVIG: intravenous immunoglobulin; JCTM: Juvenile connective tissue myositis; MMT26: Manual Muscle Testing-26; VAS: visual analog scale