Table 1

Clinical and laboratory features of elevated RDW in patients with IIM

Elevated RDW (n=101)Normal RDW (n=431)P value
Age at onset (years)52.3±13.151.7±15.20.7
Sex, F (%)83 (82)291 (67.5)0.004
Disease duration (weeks)3 (2, 6)4 (2, 12)0.09
Heliotrope sign, n (%)45 (44.5)164 (38)0.22
Mechanic’s hand, n (%)43 (42.6)134 (31.1)0.027
Gottron’s sign, n (%)55 (54.5)182 (42.2)0.026
Muscle weakness, n (%)71 (70.3)249 (57.7)0.021
Arthralgia, n (%)45 (44.5)134 (31.1)0.01
Fever, n (%)46 (45.5)85 (19.7)<0.001
ILD, n (%)81 (80.2)238 (55.2)<0.001
HGB (g/L)111.4±16.3126±18.4<0.001
T cell counts (x109/L)0.94 (0.71, 1.43)1.31 (0.82, 1.85)0.001
CK (IU/L)175 (61, 2473)266 (72, 2014)0.16
LDH (IU/L)336 (226, 527)330 (236, 531)0.1
Ferritin (ng/mL)224 (92, 694)158 (73, 499)0.5
CRP (mg/dL)0.67 (0.3, 1.2)0.35 (0.2, 0.8)<0.001
ESR (mm/hour)28 (14, 46)16 (8, 27)<0.001
  • Continuous data were presented as mean (M)±SEM or medians (IQR). Binary data are presented as n (%).

  • CK, creatine kinase; CRP, C reactive protein; ESR, erythrocyte sedimentation rate; F, female; HGB, haemoglobin; IIM, idiopathic inflammatory myopathy; ILD, interstitial lung disease; LDH, lactate dehydrogenase; RDW, red cell distribution width.