Published in:
01-05-2014 | Original Article
Usefulness of urinary CTX-II and NTX-I in evaluating radiological knee osteoarthritis : the Matsudai knee osteoarthritis survey
Published in: Journal of Orthopaedic Science | Issue 3/2014
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Background
To assess the usefulness of the urinary crosslinked C-telopeptide of type II collagen (uCTX-II) or crosslinked N-telopeptide of type I collagen (uNTX-I) for evaluating radiological knee osteoarthritis (OA), a cross-sectional study was conducted in the cohorts of the Matsudai knee osteoarthritis survey performed in Niigata, Japan.
Methods
Urine specimens and standing knee AP X-rays were obtained from 1040 subjects who provided informed consent. The relationship between these markers and gender, age (patients aged 40–59 or 60–79 years), use of bisphosphonates, and OA grades (K–L classification) were analyzed. The diagnostic ability of uCTX-II to detect radiological knee OA was confirmed in the over 60-year-old subjects using a ROC curve.
Results
The over 60-year-old men with OA grade 3,4 group had significantly higher uCTX-II levels than the other OA grade groups. In the over 60-year-old women, the uCTX-II levels significantly increased according to the progression of the knee OA grade. No significant difference was observed between the uNTX-I levels in the different OA grade groups. From the standpoint of biomarkers, the higher quartiles of the uCTX-II and uNTX-I levels gradually included higher numbers of grade ≥2 OA subjects in the over 60 year-old women. The area under the curve (AUC) in ROC analysis of uCTX-II exhibited a significant association with the diagnosis of knee OA in women (AUC 0.63), although the accuracy was evaluated to be low in the single measurement of our health checkup-based analysis.
Conclusions
This population-based study indicates that the uCTX-II level is strongly correlated with the knee OA grade in women over age 60. A further analysis is needed to clarify its predictive accuracy.