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Table 2 Demographics and MRI changes in subgroups of the ASS cohort

From: Comparative analyses of muscle MRI and muscular function in anti-synthetase syndrome patients and matched controls: a cross-sectional study

  Myositis diagnosis prior to inclusion Anti-Jo-1 positivity Myositis subtype
Yes (N = 54) No (N = 14) p value Yes (N = 53) No (N = 15) p value PM (N = 27) DMa (N = 25) p value
Age at diagnosis (years) 47 (14.3) 49 (11.5) n.s. 48 (13.9) 43 (12.8) n.s. 50 (14.9) 43 (13.7) n.s.
Disease duration (months) 76 (6–362) 22 (7–230) 0.003 76 (6–362) 35 (7–230) 0.004 70 (6–362) 83 (14–350) n.s.
Jo1/non-Jo1, n 49 / 5 4 / 10 <0.001     25 / 2 23 / 2 n.s.
Ro-52 positivity, n/N (%) 38/54 (70) 7/14 (50) n.s. 37/53 (70) 8/15 (53) n.s. 17/27 (63) 17/25 (68) n.s.
CK (U/L) 103 (38–1344) 71 (24–194) n.s. 101 (38–1344) 70 (24–572) n.s. 101 (43–437) 113 (38–1344) n.s.
MMT14 score (0–140) 139 (134, 140) 136 (127, 140) n.s. 139 (134, 140) 139.5 (131.5,140) n.s. 139 (136, 140) 137 (134, 140) n.s.
MMT4 score (0–40) 40 (36, 40) 38.5 (34, 40) n.s. 39 (36, 40) 40 (35, 40) n.s. 40 (37, 40) 39 (36, 40) n.s.
FI2 score (0–330) 212 (125, 297) 194.5 (91,320) n.s. 221.5 (129, 304) 185 (82, 301.5) n.s. 224 (87.5, 318) 210 (129.5, 288) n.s.
MRI changes
Muscle edema score (0–36) 7.49 (10.7) 0.62 (1.5) <0.001 7.86 (10.7) 0.27 (1.0) <0.001 0 (0–26) 4 (0–36) 0.039
Total edema score (0–42) 8.83 (12.0) 1.38 (2.5) <0.001 9.29 (12.1) 0.80 (2.2) <0.001 6.0 (9.6) 11.6 (13.8) n.s.
Total damage score (0–36) 6.98 (5.4) 4.15 (2.5) 0.008 7.06 (5.5) 4.27 (2.7) 0.010 7.0 (5.7) 7.1 (5.1) n.s.
Total MRI score (0–78) 15.87 (14.7) 5.54 (3.6) <0.001 16.39 (14.7) 5.13 (3.8) <0.001 13.0 (13.0) 18.8 (15.6) n.s.
  1. Data presented as mean (SD), median (range) and median (25th, 75th centile) unless indicated otherwise
  2. Data is presented as mean (SD) or median (range). For MMT14, MMT4 and FI2 data is presented with median (25th, 75th percentile)
  3. aExcept for two patients with amyopathic DM
  4. ASS anti-synthetase syndrome, MRI magnetic resonance imaging, PM polymyositis, DM dermatomyositis, n.s. not significant, CK creatinine kinase, MMT4 manual muscle test of four muscles, MMT14 manual muscle test of 14 muscles, FI2 functional index
  5. Bold text refers to significant differences