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Table 2 Demographic and clinical characteristics of IFNα-positive and IFNα-negative patients

From: Plasma interferon-alpha is associated with double-positivity for autoantibodies but is not a predictor of remission in early rheumatoid arthritis—a spin-off study of the NORD-STAR randomized clinical trial

N = 346

IFNα-negative (n = 255)

IFNα-positivea (n = 91)

p-value

Age, yearsb

58 (18–81)

58 (21–82)

0.53

Female sexc

170 (67%)

64 (70%)

0.60

BMI, kg/m2b

25 (18–43)

26 (19–43)

0.22

Current smokerc

46 (18%)

25 (27%)

0.07

Autoantibody statusc

  

< 0.0001

 RF-ACPA-

33 (13%)

3 (3%)

p < 0.05d

 RF+ACPA-

23 (9%)

2 (2%)

ns

 RF-ACPA+

52 (20%)

2 (2%)

p < 0.05d

 RF+ACPA+

146 (57%)

84 (92%)

p < 0.05d

Disease activity day 1b

   

 CDAI

27.8 (7.8–68.7)

28.6 (10.1–68.4)

0.13

 DAS28-CRP

5.1 (2.2–8.3)

5.1 (3.3–7.7)

0.38

 DAS28-ESR

5.5 (2.6–8.7)

5.5 (3.3–8.2)

0.43

 SJC-66

11 (1–42)

11 (2–38)

0.68

 TJC-68

13 (0–49)

16 (2–62)

0.16

 CRP, mg/L

14 (0.3–216)

8 (0.5–190)

0.16

 ESR, mm/h

28 (2–115)

28 (4–108)

0.26

 PGA, mm

59 (2–100)

56 (22–100)

0.59

Disease activity week 24b

   

 CDAI

3.4 (0–28.3)

3.5 (0–26.6)

0.47

 DAS28-CRP

2.0 (1.1–4.8)

2.0 (1.0–5.0)

0.82

 DAS28-ESR

2.3 (0–6.0)

2.2 (0–5.8)

0.91

 SJC-66

0 (0–9)

0 (0–7)

0.88

 TJC-68

1 (0–37)

2 (0–41)

0.22

 CRP, mg/L

1 (0–39)

1 (0.1–15)

0.86

 ESR, mm/h

8 (1–78)

8 (1–48)

0.52

 PGA, mm

11 (0–78)

14 (0–92)

0.40

  1. BMI body mass index, RF rheumatoid factor, ACPA anti-citrullinated protein antibodies, CDAI clinical disease activity index, DAS28 disease activity score 28 joints, SJC-66 swollen joint count, 66 joints, TJC-68 tender joint count, 68 joints, CRP C-reactive protein, ESR erythrocyte sedimentation rate, PGA patient global assessment
  2. aIFNα positivity defined as IFNα protein level above 136 fg/mL
  3. bMedian (range), Mann-Whitney U-test
  4. cn (%), Fisher’s exact test
  5. dp < 0.05 after post hoc step-down Bonferroni-Holm correction for multiple testing