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Table 1 Clinical characteristics of IIM patients

From: Disease activity in patients with idiopathic inflammatory myopathy according to time since diagnosis and positivity to antisynthetase autoantibodies: data from the Myo-Spain registry

Characteristic

N=

Total

554

Incident group

136

Prevalent group

418

Sociodemographic

Women

404 (72.92%)

93 (68.38%)

311 (74.40%)

Age at diagnosis (years)***

50.7 ± 17.0

55.4 ± 17.0

49.2 ± 16.7

Race

   

 Caucasian

470 (85.14%)

113 (83.09%)

357 (85.82%)

 Hispanic

64 (11.59%)

19 (13.97%)

45 (10.82%)

 African (Black and North African)

10 (1.81%)

1 (0.74%)

9 (2.16%)

 Asian

7 (1.27%)

3 (2.21%)

4 (0.96%)

 Other

1 (0.18%)

0 (0.00%)

1 (0.24%)

Months from symptom onset to diagnosis*

13.1 ± 23.7

17.4 ± 30.9

11.7 ± 20.6

Months of follow-up***

42.28 [12.39–91.82]

1.84 [0.33–5.88]

61.0 [35.24–109.68]

Meeting IIM classification criteria*

448 (80.87%)

101 (74.26%)

347 (83.01%)

Diagnostic subgroups of IIM

 Antisynthetase syndrome

215 (38.81%)

58 (42.65%)

157 (37.56%)

 Dermatomyositis

130 (23.47%)

32 (23.53%)

98 (23.44%)

 Overlap myositis syndrome

68 (12.27%)

9 (6.62%)

59 (14.11%)

 Polymyositis

59 (10.65%)

14 (10.29%)

45 (10.77%)

 Clinically amyopathic dermatomyositis

37 (6.68%)

8 (5.88%)

29 (6.94%)

 Immune-mediated necrotizing myopathy

23 (4.15%)

9 (6.62%)

14 (3.35%)

 Not classifiable

13 (2.35%)

4 (2.94%)

9 (2.15%)

 Inclusion body myositis

9 (1.62%)

2 (1.47%)

7 (1.67%)

AAb subgroups

 Myositis-associated AAb

245 (44.22%)

56 (41.18%)

189 (45.22%)

 Antisynthetase AAb&

215 (38.81%)

58 (42.65%)

157 (37.56%)

 Dermatomyositis AAb*

128 (23.10%)

42 (30.88%)

86 (20.57%)

 Seronegative*

107 (19.31%)

16 (11.76%)

91 (21.77%)

 Immune-mediated necrotizing myopathy AAb

27 (4.87%)

10 (7.35%)

17 (4.07%)

Clinical manifestations and comorbidities

Presentation

 Acute

105 (19.02%)

23 (16.91%)

82 (19.71%)

 Subacute

237 (42.93%)

59 (43.38%)

178 (42.79%)

 Chronic

210 (38.04%)

54 (39.71%)

156 (37.50%)

Characteristic skin lesions of dermatomyositis

237 (42.86%)

51 (37.50%)

186 (44.60%)

Dysphagia

180 (35.43%)

39 (31.97%)

141 (36.53%)

Calcinosis

33 (6.86%)

5 (4.55%)

28 (7.55%)

Diffuse interstitial lung disease

246 (49.2%)

55 (47.01%)

191 (49.87%)

Cancer

72 (17.82%)

20 (20.41%)

52 (16.99%)

Previous or current smoking

205 (37.21%)

51 (37.78%)

154 (37.02%)

Statins

131 (23.77%)

30 (22.22%)

101 (24.28%)

Severe infections*

61 (13.86%)

7 (6.73%)

54 (16.07%)

ICU admission since diagnosis

22 (4%)

9 (6.72%)

13 (3.13%)

Treatments since diagnosis

 

sDMARDs***

 < 2

375 (67.69%)

123 (90.44%)

252 (60.29%)

 ≥ 2

179 (32.31%)

13 (9.56%)

166 (39.71%)

bDMARDs or targeted therapies**

 0

411 (74.19%)

113 (83.09%)

298 (71.29%)

 ≥ 1

143 (25.81%)

23 (16.91%)

120 (28.71%)

Immunoglobulins and/or plasmapheresis

153 (27.62%)

32 (23.53%)

121 (28.95%)

  1. Data are shown as n (%) and mean ± standard deviation or median [interquartile range]
  2. *P < 0.05, **P < 0.01, ***P < 0.001
  3. & Antisynthetase AAb: 215 patients including 24 with skin lesions that were highly characteristic of dermatomyositis
  4. Chi-square test for categorical variables, t test for approximately normally distributed quantitative variables, and Mann-Whitney test for non-normally distributed quantitative variables
  5. IIM Idiopathic inflammatory myopathy, AAb Autoantibodies, ICU Intensive care unit, sDMARDs Synthetic disease-modifying antirheumatic drugs (methotrexate, cyclophosphamide, mycophenolate mofetil, mycophenolic acid, cyclosporine A, azathioprine, leflunomide), bDMARDs Biologic disease-modifying antirheumatic drugs and targeted therapies (rituximab, anti-TNF, abatacept, apremilast, baricitinib, tofacitinib)
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Arthritis Research & Therapy

ISSN: 1478-6362

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