Objective To explore the correlation between quantitative computed tomography (QCT), bone metabolic markers and bone quality in type 2 diabetes mellitus (T2DM) patients, and value of combined assessment in predicting the risk of fragility fractures.

Methods Eighty-two T2DM patients were selected as the observation group, and another 82 non-diabetic volunteers were selected as the control group during the same period. The blood glucose and lipid parametersglycated hemoglobin (HbA1c), fasting blood glucose (FBG), triglycerides (TG), total cholesterol (TC), bone metabolic markers25-hydroxyvitamin D (25OHD), procollagen type I amino acid extension (PINP), type I collagen carboxy terminal peptide (β-CTX), osteocalcin N-terminal mid-molecular fragment (N-MID), QCT bone mineral density (BMD) and trabecular bone score (TBS) were compared between two groups. The correlation between blood glucose and lipid parameters, QCT BMD, bone metabolic markers and TBS in T2DM patients was analyzed. Based on TBS, the risk of fragility fractures in the observation group were assessed. The blood glucose and lipid parameters, bone metabolic markers and QCT BMD were compared between patients with high and low-to-moderate fragility fracture risks. The value of each marker in assessing the risk of high fragility fractures in T2DM patients was analyzed.

Results The serum levels of HbA1c, FBG, TG, TC, PINP and β-CTX in the observation group were higher than those of the control group, while the serum levels of 25OHD, N-MID, QCT BMD and TBS were lower in the observation group (P ＜ 0.05). The QCT BMD and serum levels of 25OHD and N-MID were positively correlated with TBS, while the levels of PINP and β-CTX were negatively correlated with TBS (P ＜ 0.05). The levels of QCT BMD, serum 25OHD and N-MID in patients with high risk of fragility fractures were lower than those in patients with medium and low risk of fragility fractures, while the levels of PINP and β-CTX were higher than those in patients with medium and low risk of fragility fractures (P ＜ 0.05). The AUC of bone metabolism indicators and QCT BMD combined in predicting the risk of high fragility fractures in patients with T2DM was 0.916 (95%CI: 0.833–0.966), which was greater than that predicted by individual indicator.

Conclusions Bone metabolic markers and QCT BMD are differentially expressed in T2DM patients, and are associated with the occurrence of fragility fractures of patients. The combined prediction of these markers has good predictive value for high fragility fracture risk in T2DM patients.