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Table 2 Biomarker levels in each subgroup of the subjects according to the radiographic classification

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 Mean SE 95% CI of the mean P-value 95% CI for difference
     Lower Upper   
sC2C K/L1 5.56 0.04 5.49 5.64 0.06 -0.09 to 0.30
Ln (pmol/ml) K/L2 5.42 0.07 5.29 5.55   
sCPII K/L1 7.53 0.06 7.38 7.64 <0.01* 0.26 to 0.78
Ln (ng/ml) K/L2 6.99 0.11 6.77 7.21   
uCTX-II/Cr K/L1 5.25 0.13 4.99 5.52 0.15 -0.94 to 0.15
Ln (ng/μmol creatinine) K/L2 5.65 0.23 5.19 6.11   
sC2C/sCPII K/L1 0.14 0.02 0.10 0.18 <0.01* -0.21 to -0.04
  K/L2 0.26 0.04 0.19 0.34   
uCTX-II/sCPII K/L1 0.11 0.06 -0.01 0.22 <0.01* -0.68 to -0.22
  K/L2 0.56 0.10 0.37 0.75   
uNTx/Cr K/L1 3.79 0.10 3.60 3.98 0.10 -1.47 to -0.59
Ln (ng/ml creatinine) K/L2 3.46 0.16 3.13 3.79   
sHA K/L1 2.97 0.12 2.74 3.21 <0.01* -1.21 to -0.27
Ln (pmol/ml) K/L2 3.71 0.20 3.31 4.11   
  1. All analyses were adjusted for age, gender, and body mass index. The urinary biomarkers were corrected for creatinine. The number of subjects with K/L grade 1 was 30, while that with K/L grade 2 was 16. *P-values less than or equal to 0.05 are statistically significant. 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; SE, standard error of the mean; s, serum; u, urine.