SAT0665 PLASMA HSPRO-C2 LEVELS PREDICT RADIOGRAPHIC PROGRESSION IN SYMPTOMATIC KNEE OSTEOARTHRITIS PATIENTS

Abstract

Background There is a lack of objective diagnostic modalities that identify patients at risk for severe osteoarthritis (OA), which complicates the development of disease-modifying OA drugs. The biochemical marker, high-sensitive PRO-C2 (hsPRO-C2)1, is a measure of the propeptide of type IIB collagen and a blood measure of cartilage formation. Objectives The aim of this study was to determine whether hsPRO-C2 could predict radiographic progression in a knee OA population and stratify patients into high and low risk for joint destruction. Methods Subjects with varying degrees of symptomatic knee OA (n=106) were included from a New York University (NYU) progression cohort. Radiographic progression was assessed by medial joint space narrowing (JSN), based on the change in joint space width (JSW), of the signal knee at baseline and at 24months. Baseline plasma type II collagen formation biomarker (hsPRO-C2) levels were measured. Association between baseline hsPRO-C2 and JSN was analyzed by Pearson’s correlation, corrected for age, sex, BMI, race, baseline JSW, and non-steroids anti-inflammatory drugs (NSAID) use. Subjects were divided into quartiles of equal size depending on the hsPRO-C2 levels, and the difference in JSN was investigated. The median level of baseline hsPRO-C2 (1.48 ng/ml) was used as a cut-off for stratifying all the subjects. The difference in JSN over 24 months was investigated in patients dichotomized based on median level. The values were compared with two-way analysis of covariates (ANCOVA). Results Baseline plasma hsPRO-C2 levels were negatively correlated with the progression of radiographic joint space narrowing over 24 months (r = -0.26, p = 0.009) after adjustment for confounders (Figure 1A). Quartile analysis demonstrated a decreasing trend of hsPRO-C2 in the radiographic progression from quartile 1 to 4 (Figure 1B). One-way ANOVA revealed a significant difference in mean JSN between quartiles 1 and 4 (0.5073 mm versus -0.0691 mm, p = 0.036, Figure 1B). JSN was significantly larger in the low hsPRO-C2 patients (0.3710 mm) compared to the high hsPRO-C2 patients (0.0195 mm) (Figure 2). Conclusion These data suggest that symptomatic knee OA subjects with lower levels of hsPRO-C2 at baseline presented more radiographic medial JSN progression as compared to the subjects with higher levels of hsPRO-C2. The biomarker hsPRO-C2 may be useful for predicting OA progression.