Table 2

Association between biomarker values measured at year 1 and subsequent radiographic progression rates
Biomarker
 P value for interactiona
 Estimated annual progression rate




Mean biomarker (%)b
 Mean + one standard deviation (%)c
C2C


     Damage
 0.030*
 29
 35
     Erosion
 0.156
 24
 27
     Narrowing
 0.019*
 31
 40
C1,2C


     Damage
 0.033*
 26
 30
     Erosion
 0.195
 25
 29
     Narrowing
 0.271
 32
 36
CPII


     Damage
 0.777
 28
 28
     Erosion
 0.816
 25
 25
     Narrowing
 0.136
 33
 41
CS846-epitope


     Damage
 0.039*
 28
 34
     Erosion
 0.014*
 27
 36
     Narrowing
 0.476
 32
 35

For each biomarker, the results of the multivariable generalized estimated equation regression model for longitudinal analyses between biomarker value at year 1 after inclusion and subsequent (repeated over time) values of the log-transformed progression score are presented. C2C, marker for degradation of type II collagen in cartilage; C1,2C, marker for degradation of type I collagen and type II collagen in cartilage; CPII, marker for synthesis of the procollagen of type II collagen cartilage; CS846-epitope, marker for aggrecan turnover in cartilage. aP < 0.05 indicates that the change in the rate of progression depends significantly on the biomarker value at year 1; *interaction statistically significant (P < 0.05). bPercentage increase of radiographic damage score per year for patients with a mean value of biomarker 1 year after disease onset. cPercentage increase in radiographic damage scores per year for patients with a value one standard deviation above the mean biomarker value 1 year after disease onset.

Verstappen et al. Arthritis Research & Therapy 2006 8:R31   doi:10.1186/ar1882

Open Data