ROC曲线评价空腹C肽水平应用于2型糖尿病肾病临床诊断价值

Clinical vaule of ROC curve evaluating fasting C-peptide for diagnostic of type 2 diabetic nephropathy

目的探讨2型糖尿病(DM)患者空腹血清C肽(FCP)水平应用于糖尿病肾病(DN)的诊断意义,并采用ROC曲线选择最佳临界值并评价诊断性能。方法回顾性分析本院2006年6月至2009年8月间342例2型DM患者,其中DM组254例,DN组88例。ROC曲线选择FCP的临界值,并以此评价FCP检测值的诊断价值。结果 1)DN组FCP水平显著低于DM组(P=0.000,t=7.385),FCP诊断DN的临界值为1.20ng/mL,ROC曲线下面积为0.884±0.021,95%置信区间(95%CI)为0.844～0.925;2)诊断灵敏度为90.8%,特异性为78.0%,阳性预期值为92.9%,阴性预期值为72.7%,正确率为87.7%,Youden值为68.8%;3)DN的分期随FCP浓度的降低而逐渐升高(χ2=154.49,P<0.001),队列研究结果显示:RR=3.407,95%CI为2.418～4.800。结论 FCP水平与2型DM患者中DN的发生、发展密切相关,DM患者FCP水平低于1.20ng/mL时发生DN的风险增加,保持生理性的C肽浓度可能会延缓DN的发生与发展。

Objective To explore the diagnostic significance Of fasting connecting peptide（FCP） for diagnostic of type 2 Diabetic nephropathy（DN）. The cut-off vaule of FCP was chosen by Receiver Operation Charaeteristie（ROC）, and these efficiency index were evaluated,respectively. Methods 342 patients with DM in our hospital during June of 2006 to August of 2009 by retrospective analysis. 254 patients were in the group of DM and 88 in DN group,respectively. Results 1）The FCP level in DN group was sijnifieant lower than it in DM group,P=0. 000,t=7. 385 and the cut-off vaule was 1.20 ng/mL. Area under the curve was 0. 884 ± 0. 021, Asymptotic 95 % Confidence Interval（95 % CI） was 0. 844- 0. 925.2） Their Sensitivity, Specificity, Positive predict vaule, Negative pretict vaule, exactitude and Youden avule were 90.8 %, 78.0 %, 92.9 %, 72.7 %, 87.7 % and 68.8 %, respectively. 3） Along with the FCP level descend,The stages of DN was hoist gradually（x^2= 154.49, P〈0. 001）. Risk Estimate was 3. 407, 95%CI was 2. 418-4. 800. Conclusion There is intimate eorrelation between FCP level with the stages of DN. The risk factor of oecuring DN in FCP〈1. 20 ng/mL was higher than FCP〉1. 20 ng/mL. Remaining physiological FCP concentration in the patients with DM may delay its development of DN.