The Relationship Between Serum Cystatin C And Macroangiopathy In Patients With Type 2 Diabetes Mellitus

[OBJECTIVE]To investigate the correlation between serum cystatin C and macroangiopathy in patients with type 2 diabetes mellitus.[METHODS]156 patients with type 2 diabetes mellitus were selected in hospital,while a control group including 59 subjects without diabetes mellitus was selected from those who had physical examination.Serum cystatin C were determined by Particle enhanced turbidimetric immunoassay (PETIA).The pulse wave velocity(PWV) and the common carotid intima-media thickness(IMT) of all subjects were also assessed.All patients with type 2 diabetes mellitus were divided into three groups:the group DM1 was composed of the diabetie patients without macroangiopathy,the group DM2 was composed of the diabetie patients with subclinical macroangiopathy, and the group DM3 was composed of the diabetie patients with clinical macroangiopathy.[RESULT](1) Serum cystatin C levels increased with the progression of macroangiopathy.According to the sequence from low to high,the serum cystatin C levels were:(DM1) 0.94±0.23 mg/L,(DM2) 1.30±0.53 mg/L, (DM3) 1.51±0.64mg/L.The discrepancy of the serum cystatin C concentration was significant between random two groups among the cases (P<0.05).(2) When elevated Cys C was defined as higher than the 90th percentile of serum cystatin C concentration in contral group,the proportion of elevated CysC concentration in each group increased with the progression of macroangiopathy.The proportion in each group was:23.9%,56.14%,69.8%.There was a significant discrepancy among the groups(P<0.05).(3)All cases were divided into two groups according to the levels of IMT,such as:group normal IMT,and group thick IMT.Serum cystatin C levels increased with the thickening of IMT.And the discrepancy was significant between random two groups(P＜0.05).While a similar result was found,when grouping according to the levels of PWV (P＜0.05).(4)All subjects were divided into four equal groups according to serum cystatin C levels.The incidence of subclinical/ clinical macroangiopathy tended to increase with serum cystatin C levels,that was: 9.1%,41.5%,57.4%,and 94.3%.There was significant discrepancy among the groups(P＜0.05).(5)The correlations between serum cystatin C and IMT,PWV(C-R),PWV(C-F) were significant(P＜0.05).(6)After the stratification by renal function,serum cystatin C levels still increased with the progression of macroangiopathy within the layers.After the adjustment by stratification,there was still a significantly correlativity between serum cystatin C levels and macroangiopathy(P＜0.05),adjusted odds ratio was 2.83.(7)H-CRP levels increased with the progression of macroangiopathy(P＜0.05),while a significant correlation between serum cystatin C and h-CRP was found in patients with type 2 diabetes mellitus (P＜0.05).(8)It is suggested that cystatin C is an independent risk factor of the progression to macroangiopathy in patients with type 2 diabetes mellitus by the multiple regression procedure(P＜0.05).[CONCLUSIONS](1)There was a significantly positive correlativity between serum cystatin C levels and macroangiopathy in patients with type 2 diabetes mellitus.Serum cystatin C might be a predictor for macroangiopathy in diabetic patients.(2)The correlation was independent of renal function.(3) Inflammatory reaction might be one of the mechanism that could explain how elevated cystatin C levels increased the risk of macroangiopathy.