Association Between Biochemical Markers of Bone Turnover and Bone Changes on Imaging: Data From the Osteoarthritis Initiative.

OBJECTIVE: To determine the relationship between biochemical markers involved in bone turnover and bone features on imaging in knees with osteoarthritis (OA).

METHODS: We analyzed data from the Foundation for the National Institutes of Health OA Biomarkers Consortium within the Osteoarthritis Initiative (n = 600). Bone marrow lesions (BMLs), osteophytes, and subchondral bone area (mm2 ) and shape (position on 3-D vector) were assessed on magnetic resonance images, and bone trabecular integrity (BTI) was assessed on radiographs. Serum and urinary markers (serum C-terminal crosslinked telopeptide of type I collagen [CTX-I], serum crosslinked N-telopeptide of type I collagen [NTX-I], urinary NTX-I, urinary C-terminal crosslinked telopeptide of type II collagen [CTX-II], and urinary CTX-Iα and CTX-Iβ) were measured. The associations between biochemical and imaging markers at baseline and over 24 months were assessed using regression models adjusted for covariates.

RESULTS: At baseline, most biochemical markers were associated with BMLs, with C statistics for the presence/absence of any BML ranging from 0.675 to 0.688. At baseline, urinary CTX-II was the marker most consistently associated with BMLs (with odds of having ≥5 subregions affected compared to no BML increasing by 1.92-fold [95% confidence interval (95% CI) 1.25, 2.96] per 1 SD of urinary CTX-II), large osteophytes (odds ratio 1.39 [95% CI 1.10, 1.77]), bone area and shape (highest partial R2  = 0.032), and changes in bone shape over 24 months (partial R2 range 0.008 to 0.024). Overall, biochemical markers were not predictive of changes in BMLs or osteophytes. Serum NTX-I was inversely associated with BTI of the vertical trabeculae (quadratic slope) in all analyses (highest partial R2  = 0.028).

CONCLUSION: We found multiple significant associations, albeit mostly weak ones. The role of systemic biochemical markers as predictors of individual bone anatomic features of single knees is limited based on our findings.