Table 1 Baseline demographic and disease characteristics by Hb subgroup

Age (years)^a

N = 224

N = 890

 < 0.0001

60.38 (14.61)

55.53 (13.74)

Male^b, n (%)

N = 224

N = 890

0.3508

36 (16.07)

167 (18.76)

Caucasians^b, n (%)

N = 219

N = 889

 < 0.0001

187 (85.39)

838 (94.26)

Body mass index^a, (kg/m²)

N = 208

N = 832

0.4822

26.99 (6.34)

26.65 (5.58)

Disease duration^a, mean (SD) years

N = 223

N = 890

0.0134

14.05 (12.83)

11.71 (11.42)

Seropositive^b, n (%)

N = 214

N = 832

0.6315

150 (70.09)

569 (68.39)

RF positive^b, n (%)

N = 212

N = 808

0.5586

126 (59.43)

498 (61.63)

Anti-CCP positive^b, n (%)

N = 212

N = 823

0.1578

140 (66.04)

500 (60.75)

DAS 28-CRP4S^a, mean (SD)

N = 195

N = 791

 < 0.0001

4.46 (1.65)

3.53 (1.57)

Total swollen joints^a, mean (SD)

N = 224

N = 889

 < 0.0001

8.83 (7.85)

5.70 (6.89)

Total painful joints^a, mean (SD)

N = 224

N = 889

 < 0.0001

9.71 (8.74)

6.52 (7.36)

Medicines ever taken, n (%)

 Methotrexate^b

163 (72.77)

697 (78.31)

0.077

 Anti-TNF^b

93 (41.52)

406 (45.62)

0.27

 Plaquenil^b

135 (60.27)

531 (59.66)

0.8689

 Biologic DMARD

97 (43.30)

412 (46.29)

0.4222

 Non-biologic DMARD

210 (93.75)

848 (95.28)

0.3486

 Non-biologic DMARD, not including MTX or Plaquenil^b

121 (54.02)

414 (46.52)

0.0446

 Steroid^b

182 (81.25)

713 (80.11)

0.7018

Current medicines, n (%)

 Methotrexate^b

107 (47.77)

491 (55.17)

0.0471

 Anti-TNF^b

67 (29.91)

315 (35.39)

0.1223

 Anti-TNF and MTX^b

32 (14.29)

170 (19.10)

0.0945

 Plaquenil^b

41 (18.30)

163 (18.31)

0.997

 NSAIDs^b

133 (59.38)

439 (49.33)

0.0072

 Any DMARD^b

192 (85.71)

804 (90.34)

0.0445

 Biologic DMARD^b

74 (33.04)

347 (38.99)

0.1005

 Non-biologic DMARD^b

159 (70.98)

673 (75.62)

0.1538

 Non-biologic DMARD, not including MTX or Plaquenil^b

47 (20.98)

139 (15.62)

0.0543

 Steroid^b

74 (33.04)

252 (28.31)

0.1651