Objective: This study's aim was to investigate the expression changes of total type I procollagen amino-terminal peptide (t-PINP) and type I collagen C-terminal peptide (β-CTX) in serum after vertebral osteoporotic fracture surgery and the clinical value of predicting the risk of refracture.
Patients and methods: The clinical data of 100 patients with vertebral osteoporotic fractures treated in our hospital from January 2019 to January 2020 were retrospectively analyzed, and the patients were divided into the control group (patients without re-fracture, n = 68) and the observation group (patients with re-fracture, n = 32) according to whether they had re-fracture at 2-year follow-up. The risk factors of postoperative re-fracture were analyzed using Multivariate logistic regression analysis. The serum contents of t-PINP, β-CTX, osteocalcin (BGP), and calcium (Ca) were measured. Bone mineral density (BMD) was measured by bone densitometer. The correlation between the t-PINP/β-CTX ratio and the bone metabolic index was analyzed by Pearson correlation. The area under the curve (AUC), sensitivity, and specificity of t-PINP/β-CTX in predicting the risk of re-fracture were determined by the receiver operating characteristic (ROC) curve.
Results: There was a significant difference in age, the number of vertebral bodies with initial fracture, and whether there was leakage of bone cement between the two groups (p < 0.05). Age, the number of vertebral bodies with primary fracture, and the leakage of bone cement were risk factors affecting re-fracture after operation (p < 0.05). Compared with those in the control group, the level of t-PINP and the ratio of t-PINP/β-CTX were higher, and the β-CTX level was lower in the observation group (p < 0.05). The BGP level was higher, and the levels of BMD and Ca were lower in the observation group than those in the control group (p < 0.05). Pearson correlation analysis showed that t-PINP had a positive correlation with BGP (r = 0.222, p < 0.05). β-CTX was positively correlated with BMD and Ca (r = 0.230, 0.269, p < 0.05). The ratio of t-PINP/ β-CTX was negatively correlated with BMD and Ca (r = -0.621 and -0.660, p < 0.05), but positively correlated with BGP (r = 0.517, p < 0.05). ROC curve analysis showed that the AUC of t-PINP, β-CTX, and the ratio of t-PINP/β-CTX in predicting the risk of re-fracture after vertebral osteoporotic fracture surgery was 0.724, 0.736, and 0.838, respectively.
Conclusions: The t-PINP/β-CTX ratio was significantly correlated with the bone metabolic indexes in patients with vertebral osteoporotic fractures. The detection of the changes in its index can help predict the risk of postoperative re-fracture, providing a new idea for clinical assessment of the risk of postoperative re-fracture.