The Significance Of Serum Cystatin-C And β₂-microglobulin In The Assessment Of Type 2 Diabetic Patients With Kidney Injury

Purpose: To investigate the clinical value of serum Cystatin-C(Cys C) andβ2-microglobulin(β2-MG) in the assessment of type 2 diabetic patients with kidney injury. Appraise the significance of forecasting the diabetic patients with nephropathy.Methods: 131 patients with type 2 diabetes were collected as case group. 45 type 2 diabetic patients without microalbuminuria(NA group),44 type 2 diabetic patients with microalbuminuria(MA group) and 42 with clinical albuminuria(CP group),and 48 cases were healthy controls. The levels of Cys C and β2-MG between the four groups were compared.Results: The index of Cys C and β2-MG in CP group were significantly higher than that of MA group, and the index of Cys C and β2-MG in MA group(UAER 30 ~ 300mg/24h) were significantly higher than that of NA group(UAER<30mg/24h), the difference was statistically significant(P<0.05).The sensitivities for detection of DN used cutoff values were 80.2% for Cys C, 52.3% for β2-MG,65.1% for Scr and 44.2% for BUN. For Cys C, the area under the ROC is 0.854. For β2-MG, the area under the ROC is 0.733. For Scr, the area under the ROC is 0.796. For BUN, the area under the ROC is 0.657. Both Cys C and β2-MG were with the high accuracies and sensitivities for detecting DN, and the accuracy and sensitivity of Cys C were highest. Serum Cys C, β2-MG, Scr, BUN showed significant(P<0.001) inverse correlation with e GFR(r’s=-0.819,-0.700,-0.736 and-0.534,respectively). Serum Cys C showed the greatest inverse correlation with e GFR.Conclusion: Serum Cys C would increase with the albuminuria increasing and DN aggravating. Cys C was valuable for evaluating the injury of kidney in diabetic patients. Serum Cys C was effective for detection of the early stage of DN with microalbuminuria. Both serum Cys C and β2-MG have great diagnostic accuracies for DN. And the diagnostic accuracies and sensitivity of serum Cys C are superior to that of serum β2-MG, Scr and BUN. Serum Cys C and β2-MG showed significant correlation with e GFR. The increase of serum Cys C and β2-MG remaindered the decrease of GFR. So Cys C and β2-MG were effective for detection of e GFR.