Figure 1.

Boxplots of biomarkers levels during follow-up (1–4 years) for patients with slow radiographic progression (<2.33 Sharp/van der Heijde units per year; shaded boxplot) versus patients with rapid radiographic progression (>7.35 Sharp/van der Heijde units per year; white boxplot) based on the 33rd and 66th percentile of annual radiographic progression. Boxplots show the median value and (IQ_0.25–0.75). Lines outside boxes represent the 10th and 90th percentiles. **Statistically significant (P < 0.05) difference between the group of patients with rapid radiographic progression versus the group of patients with slow radiographic progression. 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.