TABLE 3.
Demographic and disease onset data for patients with juvenile myositis categorized by myositis autoantibodies
| Total (n=374) |
Anti- synthetase (n=19) |
Anti-SRP (n=6) |
Anti-Mi-2 (n=11) |
Anti- p155/140 (n=131) |
Anti-MJ (n=86) |
MSA and MAA Negative (n=121) |
||
|---|---|---|---|---|---|---|---|---|
| Median [IQR] |
Median [IQR] | Median [IQR] |
Median [IQR] | Median [IQR] |
Median [IQR] |
Median [IQR] |
Significant Differences* |
|
| Age at diagnosis (y) | 7.4 [5.1- 11.7] |
14.0 [7.5-16.7] | 15.1 [12.1- 16.2] |
10.8 [6.8-15.0] | 7.2 [5.1- 11.0] |
6.2 [4.3- 10.3] |
7.9 [5.3- 11.4] |
Synth vs. MJ4, Synth vs. p155/1404, Synth vs. None4, SRP vs. MJ4, SRP vs. p155/1404, SRP vs. None4 |
| Age at onset (y) | 6.9 [4.0- 11.0] |
12.3 [7.1-15.0] | 14.6 [11.6- 16.1] |
10.7 [6.7-14.9] | 7.0 [3.8- 10.4] |
5.8 [3.9- 10.2] |
6.8 [4.4- 10.4] |
Synth vs. MJ4, Synth vs. p155/1404, , Synth vs. None4, SRP vs. MJ4, SRP vs. p155/1404, SRP vs. None3 |
| Delay in diagnosis (mo) | 4.1 [2.0- 9.1] |
5.9 [2.0 -13.2] | 1.9 [1.6-6.3] | 2.0 [1.0-5.1] | 4.6 [2.0- 9.1] |
3.0 [1.0- 7.0] |
4.1 [2.0- 10.1] |
MJ vs. p155/1402, MJ vs. None1 |
| Disease duration (y) | 4.4 [2.2- 7.9] |
2.3 [1.1-5.6] | 6.1 [3.1-8.3] | 7.3 [3.6-10.4] | 4.8 [2.1- 8.9] |
4.1 [2.8- 7.9] |
4.4 [2.2- 7.2] |
Synth vs. Mi- 23,Synth vs. MJ2, Synth vs. None1 |
|
| ||||||||
| n (%) | n (%) | n (%) | n (%) | n (%) | n (%) | n (%) | ||
|
| ||||||||
| Gender: female | 271 (72.5) | 16 (84.2) | 4 (66.7) | 7 (63.6) | 102 (77.9) | 60 (69.8) | 82 (67.8) | |
| Race | ||||||||
| White | 258 (69.7) | 10 (52.6) | 1 (16.7) | 2 (18.2) | 105 (80.2) | 62 (72.1) | 78 (64.5) | Synth vs. Mi-21, Synth vs. p155/1402, SRP vs. MJ3, SRP vs. p155/1404, SRP vs. None4, Mi-2 vs. MJ4, Mi-2 vs. p155/1404, Mi-2 vs. None4, MJ vs. p155/1401, p155/140 vs.None2 |
| Black | 52 (13.9) | 6 (31.6) | 5 (83.3) | 3 (27.3) | 7 (5.3) | 14 (16.3) | 17 (14.0) | |
| Other | 64 (17.1) | 3 (15.8) | 0 (0.0) | 6 (54.5) | 19 (14.5) | 10 (11.6) | 26 (21.5) | |
| Onset speed | ||||||||
| Insidious (≥ 6 mo) | 134 (35.8) | 11 (57.9) | 2 (33.3) | 2 (18.2) | 50 (38.5) | 26 (30.2) | 42 (34.5) | Synth vs. Mi-22, Synth vs. MJ1, Synth vs. p155/1402, Synth vs. None4 |
| Slow (3-6 mo) | 106 (28.4) | 3 (15.8) | 1 (16.7) | 5 (45.4) | 33 (25.4) | 22 (25.6) | 42 (34.5) | |
| Subacute (1-3 mo) | 92 (24.6) | 1 (5.3) | 3 (50.0) | 4 (36.4) | 33 (25.4) | 26 (30.2) | 25 (20.5) | |
| Acute (< 1 mo) | 42 (11.2) | 4 (21.0) | 0 (0.0) | 0 (0.0) | 14 (10.7) | 12 (14.0) | 13 (10.5) | |
| Severity of onset | ||||||||
| Mild or moderate | 262 (70.1) | 9 (47.4) | 0 (0.0) | 7 (63.6) | 100 (76.3) | 59 (68.6) | 88 (72.7) | Synth vs. p155/1402, SRP vs. Mi-23, SRP vs. MJ3, SRP vs. p155/1404, SRP vs. None3, MJ vs. p155/1401, p155/140 vs. None1 |
| Severe or very severe | 112 (29.9) | 10 (52.6) | 6 (100.0) | 4 (36.4) | 31 (23.7) | 27 (31.4) | 33 (27.3) | |
Abbreviations: MSA = myositis-specific autoantibodies; MAA = myositis-associated autoantibodies.
Note that percentages may not reflect the number divided by the total number of subjects, if data are missing.
*
Significant differences
1
p < 0.05
2
p < 0.01
3
p < 0.005
4
p < 0.001
Abbreviations of autoantibodies: Synth = anti-synthetase; MJ = anti-MJ; p155/140 = anti-p155/140; SRP = anti-signal recognition particle; Mi-2 = anti-Mi-2.