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Table 4 Biomarker levels in each subgroups according to both the radiographic classification and knee pain

From: Relationships between biomarkers of cartilage, bone, synovial metabolism and knee pain provide insights into the origins of pain in early knee osteoarthritis

  Radiographic OA Pain Mean SE 95% CI of the mean P-value 95% CI for difference
      Lower Upper   
sC2C K/L 1 - 5.49 0.04 5.40 5.57 0.02* -0.19 to -0.04
Ln (pmol/ml)   + 5.75 0.07 5.61 5.91   
  K/L 2 - 5.43 0.07 5.29 5.57 1.00 -0.36 to 0.35
   + 5.44 0.11 5.21 5.66   
sCPII K/L 1 - 7.38 0.07 7.24 7.52 0.01* -0.83 to -0.10
Ln (ng/ml)   + 7.84 0.11 7.62 8.07   
  K/L 2 - 7.05 0.11 6.83 7.28 1.00 -0.44 to 0.71
   + 6.92 0.18 6.56 7.28   
uCTX-II/Cr K/L 1 - 5.04 0.14 4.76 5.32 0.07 -1.48 to 0.03
Ln (ng/μmol creatinine)   + 5.77 0.22 5.32 6.22   
  K/L 2 - 5.38 0.23 4.92 5.83 <0.05* -2.36 to -0.05
   + 6.56 0.36 5.82 7.29   
sC2C K/L 1 - 0.15 0.03 0.10 0.20 1.00 -1.12 to 0.17
/sCPII   + 0.12 0.04 0.04 0.21   
  K/L 2 - 0.27 0.04 0.19 0.36 1.00 -0.17 to 0.26
   + 0.23 0.07 0.09 0.37   
uCTX-II/sCPII K/L 1 - 0.09 0.06 -0.03 0.22 1.00 -0.39 to 0.29
   + 0.14 0.10 -0.06 0.35   
  K/L 2 - 0.42 0.10 0.21 0.63 <0.05* -1.07 to 0
   + 0.95 0.17 0.62 1.29   
uNTX/Cr K/L 1 - 3.71 0.11 3.48 3.93 1.00 -0.89 to 0.33
Ln (ng/ml creatinine)   + 3.99 0.18 3.62 4.35   
  K/L 2 - 3.33 0.18 2.96 3.70 0.73 -1.49 to 0.41
   + 3.87 0.29 3.27 4.47   
sHA K/L 1 - 2.77 0.13 2.51 3.03 0.06 -1.40 to 0.01
Ln (pmol/ml)   + 3.46 0.21 3.04 3.89   
  K/L 2 - 3.66 0.21 3.24 4.09 1.00 -1.42 to 0.78
   + 3.98 0.34 3.29 4.67   
  1. All analyses were adjusted for age, sex and body mass index. The urinary biomarkers were corrected for creatinine. *P-values less than or equal to 0.05 are statistically significant.
  2. 95% CI, 95% confidence interval; C2C, cartilage collagen type II cleavage; CPII, cartilage type II collagen carboxy propeptide; CTX-II, type II collagen C-telopeptide; HA, hyaluronic acid; K/L, Kellgren-Lawrence grade; Ln, natural log; NTx, N-terminal crosslinking telopeptide of type I collagen; s, serum; SE, standard error of the mean; u, urine.