尿胱抑素C作为糖尿病肾病早期诊断标准的评价

目的 评估尿胱抑素C （urinary cystatin C,UCysC）与尿白蛋白/肌酐（urine albumin-creatinine ratio,UACR）的相关性,进而探讨UCysC作为糖尿病肾病（diabetic nephropathy,DN）早期诊断标准的意义.方法 采取回顾性横断面研究方法,将100例糖尿病（diabetes mellitus,DM）患者依据UACR水平分为正常白蛋白尿组（n=19）、微量白蛋白尿组（n=59）和大量白蛋白尿组（n=22）.常规记录查体结果和相关生化指标,同时采用颗粒增强透射免疫比浊法（particle-enhanced turbimetric assay method）测定不同分组患者UCysC水平.结果 在正常白蛋白尿组、微量白蛋白尿组和大量白蛋白尿组,UCysC随着UACR的增加而逐渐升高,差异具有统计学意义（P＜0.05）.UCysC与UACR之间呈正相关（r=0.766,P=0.000）,以UACR值30mg/g为切入点,作ROC曲线,得出曲线下面积为0.915,这说明UCysC对于早期DN来说,具有很好的敏感度和特异性.结论 UCysC与UACR之间具有独立相关性,UCysC可以作为DN早期诊断标准.

Evaluation of Urinary Cystatin C as the Standard for Early Diagnosis of Diabetic Nephropathy

Objective This study aimed to evaluate the association between urinary cystatin C （UCysC） and urine albumin-creatinine ratio （UACR） and then to determine whether urinary cystatin C could be used as an early biomarker of renal dysfunction in diabetic patients.Methods Diabetic patients （n =100） with normoalbuminuria （n =19）,microalbuminuria （n =59） and macroalbuminuria （n =22） were enrolled in the study.Urine cystatin C,serum creatinine （Scr）,blood urine nitrogen （BUN）,urine albumin-creatinine ratio （UACR） and other blood biochemical values were determined in all groups.Particle-enhanced turbimetric assay method was used to measure urinary cystatin C levels in different groups.Results In normoalbuminuria group,microalbuminuria group and macroalbuminuria group,the urine cystatin C levels increased with increasing degree of urine ACR,and the differences between the groups were statistically significant （P ＜ 0.05）.Urine cystatin C was positively corrected with urine ACR （r =0.766,P =0.000）.Nonparametric ROC curve,using a cut of urine ACR of 30mg/g,was obtained for urine cystatin C.Area under the curve was 0.915 for urine cystatin C,which meanst that urine cystatin C was sensitive and specific in the early stage of diabetic nephropathy.Conclusion There is an independent correlation between cystatin C and urine ACR.The results of this study suggest that urinary cystatin C could be a biomaker of incipient DN.