Abstract: Objective To explore the clinical significance of bone mineral density (BMD),serum 25 hydroxyvita-min D₃[25-(OH)D₃],uncarboxylated osteocalcin (ucOC) and sarcopenia in patients with type 2 diabetes nephro- pathy(T2DN). Methods From August 2023 to August 2024,197 patients with T2DN admitted to the department of Endocrinology, People's Hospital of Wuhan University were assigned into sarcopenia group (80 cases) and non-sarcopenia group (117 cases) according to whether the patients had sarcopenia or not. ELISA reagent test kit was applied to detect the levels of serum 25-(OH)D₃ and ucOC. Dual energy X-ray absorptiometry (DXA) was applied to detect the BMD value of the patients. The Modified Quantitative Subjective Global Assessment(MQSGA) was applied to evaluate the nutritional status of patients. The correlation between BMD value, 25-(OH)D₃, ucOC and sarcopenia index and MQSGA score was analyzed by Pearson and Spearman methods. Multivariate Logistic regression model was used to analyze the factors affecting sarcopenia in T2DN patients. Receiver operating characteristic (ROC) curve was used to analyze the auxiliary diagnostic value of BMD value, serum 25-(OH)D₃ and ucOC for sarcopenia in T2DN patients. Results Value and serum 25-(OH)D₃ level in sarcopenia group were lower than those in non-sarcopenia group, and serum ucOC level was higher than those in non sarcopenia group (t/P=9.963/＜0.001,8.948/＜0.001,9.913/＜0.001). Compared to the non-sarcopenia group, participants in the sarcopenia group exhibited significant reductions in grip strength, gait velocity, and ASMI,but sitting time and MQSGA score were higher than those in the non-sarcopenia group (t/P=8.330/＜ 0.001,15.198/＜0.001,8.230/＜0.001,6.934/＜0.001,3.528/0.001). In sarcopenic 2DN patients,BMD and serum 25-(OH)D₃ levels demonstrated positive correlations with grip strength, walking speed and ASMI,while showing inverse associations with sitting time and MQSGA score [BMD value: r_s/P=0.492/＜0.001,0.469/＜0.001,0.492/＜0.001,-0.513/＜0.001,-0.523/＜0.001; 25-(OH)D₃: r_s/P=0.537/＜0.001,0.472/＜0.001,0.496/＜0.001,-0.562/＜0.001,-0.523/＜0.001]. Serum ucOC concentration demonstrated inverse correlations with grip strength, walking speed, and ASMI,while showing positive associations with sitting time and MQSGA score (r_s/P=-0.546/＜0.001,-0.493/＜0.001,-0.487/＜0.001,0.541/＜0.001,0.544/＜0.001). Elevated serum ucOC level is an independent risk factor for sarcopenia in T2DN patients [OR(95% CI)=1.953(1.279-2.982)]. BMD and elevated serum 25-(OH)D₃ levels were independent protective factor[OR(95% CI)=0.316(0.135-0.741),0.287(0.133-0.621)]. The area under the curve (AUC) of BMD,serum 25-(OH)D₃ and ucOC levels in T2DN patients with sarcopenia were 0.838,0.817,0.863 and 0.956,respectively,and the AUC of the combination of the three(triple detection) was greater than that of the single diagnosis (Z/P=4.549/＜0.001,5.109/＜0.001,4.010/0.001). Conclusions In addition to BMD value, serum 25-(OH)D₃ and ucOC are also important biomarkers in patients with T2DN. Triple detection can support to diagnose sarcopenia in T2DN patients.

Key words: type 2 diabetes nephropathy, sarcopenia, bone mineral density, 25-hydroxyvitamin D3, uncarboxylated osteocalcin