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Table 1 Study population characteristics

From: Scleroderma-polymyositis overlap syndrome versus idiopathic polymyositis and systemic sclerosis: a descriptive study on clinical features and myopathology

Characteristics Number SSc-overlap (n = 25) Number SSc (n = 397) Number PM (n=40) P value
Age in years, mean (SD) 25 53 (12.3) 397 50 (13.2) 40 51 (16.5) 0.013
Gender (male/female) 25 12/13 397 131/266 40 25/15 0.003
 Type diagnosis        
Limited cutaneous   19 (76%)   276 (73%)   NA NS
Diffuse cutaneous   6 (24%)   109 (27%)    
Disease duration, years median (IQR) 25 5 (3–12) 397 7 (3–14) 40 3.5 (2–11) 0.001
Mortality 25 8 (32%) 397 65 (16%) 40 7 (18%) NS
Survival in years, median (IQR) 8 2.5 (1.3-9.6) 65 7 (3–13.5) 7 0.3 (0–12) NS
Serology        
ANA 25 25 (100%) 397 356 (90%) 34 21 (62%) 0.006
Anti-topoisomerase 21 0 397 87 (22%) 31 1 (3%) 0.048
Anti-centromere 19 2 (10%) 397 76 (19%) 31 0 NS
Anti-SSA 25 2 (8%) 397 15 (4%) 31 11 (36%) < 0.001
Anti-SSB 25 0   NA 31 1 (3%) NS
Anti-RNP 25 2 (8%) 397 27 (7%) 31 2 (6%) NS
Anti-SM 25 0   NA 31 2 (6%) NS
Anti-Jo1 25 2 (8%)   NA 31 13 (42%) 0.013
  1. NA, not applicable; NS, not significant.