Serum CTRP3 and CysC correlate with glucose, lipid, and bone metabolism in elderly patients with type 2 diabetes mellitus complicated with osteoporosis

ABSTRACT Objective This study analyzed the correlation between serum C1q/TNF‐related protein 3 (CTRP3) and cystatin C (CysC) and glucose‐lipid metabolism, bone mineral density (BMD), and bone metabolism markers in elderly patients with type 2 diabetes mellitus (T2DM) complicated with osteoporosis (OP). Methods A retrospective analysis was conducted on 235 patients with T2DM admitted to Taizhou Municipal Hospital between January 2021 and June 2024. They were categorized into the T2DM group (n = 131) and the T2DM + OP group (n = 104). A healthy control group (n = 95) was established, comprising elderly individuals without diabetes or OP. Serum CTRP3 and CysC were measured. The correlation between serum CTRP3 and CysC levels and relevant metabolism markers and BMD was analyzed. The diagnostic values of serum CTRP3 and CysC were assessed, as well as their role in T2DM + OP. Results Serum CTRP3 was lower and CysC was higher in the T2DM + OP group. Serum CTRP3 and CysC levels in the T2DM + OP group were correlated with some indicators of glucose‐lipid metabolism and bone metabolism and BMD. The area under the curve (AUC) values of serum CTRP3 and CysC levels in distinguishing T2DM + OP were 0.719 and 0.702 (sensitivity: 60.58%; 61.54%, specificity: 74.05%; 74.05%), respectively, with their combination showing better performance (AUC: 0.773, sensitivity: 76.92%, specificity: 64.89%). Elevated serum CysC (OR: 1.422, 95%CI: 1.161–1.742) and CTRP3 (OR: 0.960, 95%CI: 0.943–0.976) were independent risk and protective factors for T2DM + OP in elderly patients, respectively (all P < 0.05). Conclusion CTRP3 and CysC combined detection helps distinguish OP in elderly patients with T2DM.