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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