Application value of serum cystatin C and β2-microglobulin detection in early diagnosis of diabetic nephropathy

Qu Fang

doi:10.3969/j.issn.1674-7151.2024.04.010

Abstract：Objective To explore the application value of serum cystatin C and β2-microglobulin detection in diagnosis of early renal injury in type 2 diabetes mellitus.Methods From July 2021 to June 2023,the 118 patients with diabetic nephropathy and 65 patients with simple type 2 diabetes mellitus were selected from the elderly patients with type 2 diabetes mellitus admitted in Gaomi People's Hospital,and were respectively included in diabetic nephropathy group and simple diabetes group.Additionally,100 healthy individuals undergoing physical examinations at the hospital during the same period were selected and included in healthy control group.The latex immunoturbidimetric method was used to detect serum cystatin C and β2-microglobulin,and the detection results of three groups were compared.The clinical diagnosis results were taken as"gold standard"(the patients with diabetic nephropathy were taken as positive control,and the patients with type 2 diabetes mellitus were taken as negative control),the diagnosis results of serum cystatin C and β2-microglobulin for diabetic nephropathy were compared.The consistency between the diagnostic results of serum cystatin C and β2-microglobulin detection and"gold standard"was analyzed using Kappa test.Results The levels of serum cystatin C and β2-microglobulin in diabetic nephropathy group were higher than those in simple diabetes group and healthy control group,and the differences were statistically significant[cystatin C(mg/L):1.79±0.42 vs.1.23±0.30,0.58±0.19;β2-microglobulin(mg/L):2.57±0.61 vs.1.89±0.54,1.14±0.35;all P<0.05],and the levels of serum cystatin C and β2-microglobulin in simple diabetes group were higher than those in healthy control group,with statistically significant differences(both P<0.05).There were no statistically significant differences in sensitivity,specificity,accuracy,positive predictive value and negative predictive value of independent detection of serum cystatin C and β2-microglobulin for the diagnosis of diabetic nephropathy(sensitivity:89.83%vs.88.98%;specificity:83.08%vs.86.15%;accuracy:87.43%vs.87.98%;positive predictive value:90.60%vs.92.11%;negative predictive value:81.82%vs.81.16%;all P>0.05).The diagnostic results of serum cystatin C and β2-microglobulin tested separately were highly consistent with the"gold standard"(κ values were 0.834 and 0.802,respectively).Conclusions The abnormal increase of serum cystatin C and β2-microglobulin levels is common in patients with diabetic nephropathy.The detection of two indicators has a good auxiliary diagnostic value in early diabetic nephropathy.