Correlation Of Serum Complement Protein C3a With Diabetic Kidney Disease

Objective: To investigate the correlation between serum C3 a levels and the development of diabetic kidney disease(DKD)in patients with type 2 diabetes mellitus(T2DM),and to investigate the diagnostic value of serum C3 a on DKD and its effect on the progression of renal function in patients with T2 DM.Methods:Serum C3 a levels were measured in T2 DM patients hospitalized at the Second Affiliated Hospital of Kunming Medical University from March 2022 to September 2022,and patient demographic and laboratory data were collected.First,to clarify whether serum C3 a was an independent risk factor for the development of DKD in T2 DM,patients were divided into the diabetes mellitus without kidney damage(NDKD)group and the diabetic kidney disease(DKD)group,and the serum C3 a levels and clinical data of patients in the NDKD and DKD groups were compared,and univariate and multifactor binary logistic regression were used to analyze the association between C3 a and the development of T2 DM DKD correlation.Then subject operating characteristic(ROC)curves were plotted,and the area under the curve(AUC)was used to assess whether each factor had diagnostic value for DKD.To further clarify whether serum C3 a has diagnostic value for the development of early renal damage in DKD in T2 DM,patients in the DKD group with 30 ≤ UACR < 300 or 60 ≤ e GER ≤ 90 were defined as having early DKD based on estimated glomerular filtration rate [e GFR ml/(min-1.73 m2)],random urinary albumin/creatinine ratio [UACR(mg/g)].Patients with 30≤UACR<300 or 60≤e GER≤90 in the DKD group were defined as the DKD early kidney damage group,and ROC curves were drawn to assess the diagnostic value of serum C3 a for DKD early kidney damage and to determine its sensitivity and specificity.To investigate whether serum C3 a was associated with the progression of renal function in T2 DM patients,the correlation between serum C3 a,clinical indicators and UACR and e GFR was first analyzed by Spearman’s method;then T2 DM patients were divided into three groups according to e GFR [ml/(min-1.73 m2)] levels: group A(e GFR ≥ 90),group B(60≤e GFR<90),and group C(e GFR<60),compared the serum C3 a levels among the three groups,and further analyzed the correlation between serum C3 a and the progression of renal function in T2 DM patients by ordered multicategorical logistic regression.Results:1.173 patients with T2 DM were included,including 45 patients with DKD(26.01%).serum C3 a levels in the NKD and DKD groups were significantly different,and the serum C3 a level in the DKD group [452.41(325.18,591.33)ng/ml] was significantly higher than that in the NKD group [183.23(94.28,310.60)ng/ml].)ng/ml],and the difference between the two groups was statistically significant(P < 0.05).2.Univariate and multifactorial binary logistic regression analysis showed that serum C3a(OR=1.005,95% CI 1.003 to 1.007,P<0.001),duration of diabetes(OR=1.067,95% CI 1.008 to 1.128,P=0.025),uric acid(OR=1.005,95% CI 1.002 ~to 1.009,P=0.005),and N-acetyl-β-D-aminoglucosidase/urinary creatinine(NAG/UCr)(OR=1.071,95% CI 1.016 to 1.029,P=0.011)were independently associated with the development of DKD in patients with T2 DM.3.ROC curve analysis showed that serum C3 a had a high diagnostic value(AUC=0.867)for the development of DKD in patients with T2 DM,with a sensitivity of 88.6%,a specificity of 73.6% and an optimal cut-off value of 285.05 ng/ml.4.Serum C3 a had diagnostic value in T2 DM patients presenting with early renal damage(AUC=0.797),with a sensitivity of 95.5%,specificity of 61.6%,and optimal cut-off value of 225.89 ng/ml.5.Spearman correlation analysis showed that serum C3 a levels were positively correlated with UACR and negatively correlated with e GFR(P < 0.05),and the highest correlation was found with serum C3 a compared with other clinical indicators.6.Grouped by e GFR [ml/(min-1.73 m2)] levels,serum C3 a levels increased with decreasing e GFR among group A(e GFR ≥ 90),group B(60 ≤ e GFR < 90),and group C(e GFR < 60)(P < 0.05).Further ordered multicategorical logistic regression analysis showed that serum C3 a was independently associated with the progression of renal function in T2 DM patients and was not affected by confounding factors such as age and gender.Conclusions:1.Serum C3 a was independently associated with the development of DKD in patients with T2 DM.2.Serum C3 a has a certain diagnostic value for DKD with high sensitivity and specificity.When the critical value reaches 225.89 ng/ml,it can be used as an early warning value for early renal damage,and when it is greater than 285.05 ng/ml,the occurrence of DKD needs to be alerted.3.serum C3 a levels were positively correlated with UACR levels and negatively correlated with e GFR in T2 DM patients.4.serum C3 a was independently correlated with eGFR progression in T2 DM patients.