Table 2

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

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

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.

Ishijima et al. Arthritis Research & Therapy 2011 13:R22   doi:10.1186/ar3246