A nomogram for predicting osteoarthritis based on serum biomarkers of bone turnover in middle age: A cross-sectional study of PTH and β-CTx

The objective of this study was to investigate the diagnostic model of osteoarthritis by bone turnover markers in Chinese middle-aged subjects. The study was designed as a cross-sectional investigation with 305 participants aged 45 to 64. Radiographs of tibiofemoral knee joints were used for diagnose osteoarthritis. Radiographic grading, evaluated using the Kellgren and Lawrence grading scale (K-L), was scored by 2 experienced observers who were blinded to the source of subjects. An optimal model was developed by logistic regression. And the prognostic performance of the selected model was assessed by the area under the receiver operating characteristic curve. The prevalence of osteoarthritis was 52.29% (n = 137/262) in middle age. β-CTx levels tended to increase according to the K-L grades, whereas PTH levels significantly decrease. levels of 25(OH)D, β-CTx, and PTH were each significantly associated with osteoarthritis risk (P < .05). Based on the estimated parameters of the optimal model, a nomogram was constructed for predicting osteoarthritis. These data suggest that the combination of PTH and β-CTx could significantly improve the prognosis of osteoarthritis in middle age, and that the nomogram can assist primary physicians in the identification of high-risk men.