肾小球滤过率估算方程诊断性能评价

Evaluation of diagnostic performance of glomerular filtration rate estimating equation

日的评价基于血清肌酐（SCr）、胱抑素C（CysC）的估算肾小球滤过率（eGFR）方程的诊断性能。方法以锝-二乙三胺五乙酸（99mTcDTPA）测定的99mTc—GFR为标准，测定105例患者SCr及CysC浓度，以KDIGO（2013）指南推荐的eGFR方程计算eGFR值，再计算灵敏度、特异度等系列诊断性能指标并进行统计分析，最后评价各eGFR方程的诊断效率。结果eGFR—SCr／CysC方程在临界值为90、60和45mL／min／1．73衍时，其阳性似然率（分别为9．3、30．1和13）和比数比（分别为21．1、68．4和39．4）最高，诊断性能最佳；当eGFR临界值取60mL／min／1．73m2时，eGFR—SCr／CysC的阳性似然率和比数比为30．1和68．4，SCr／CysC联合方程最能确定诊断，而阴性似然率在0．33—0．49之间，均不能有效排除诊断；eGFR—CysC的诊断性能稍优于eGFR—SCr。将方程两两联合的平行试验只有当eGFR临界值取60mL／min／1．73m2时，eGFR．（CysC＋SCr／CysC）的阳性似然率和比数比（20．8，94．5）都最高，最能确定诊断；平行试验的eGFR阴性似然率（0．12～0．22）均比eGFR单独试验的阴性似然率（0．33～0．49）低，较排除诊断的能力增强。结论临床使用eGFR应考虑同时检测血清SCr和CysC的浓度，运用eGFR—SCr／CysC联合方程评价肾损害更为准确。

Objective To evaluate the diagnostic performance of estimated glomerular filtration rate （eGFR） based on serum creatinine （SCr） and serum cystatin C （ CysC）. Methods The concentrations of SCr and CysC were determined in 105 patients, whose GFRs were estimated by measuring 99aTc-DTPA clearance as the reference. Values of eGFR were calculated with eGFR algorithms recommended by Kidney Disease Improving Global Outcomes （KDIGO） guidance （2013 version）. Diagnostic sensitivity, specificity, and likelihood ratios were calculated, and eGFR accuracies were assessed with receiver operator characteristic curve （ROC） analysis. Results When the cut-off values of the eGFR-SCr/CysC equation were 90, 60, and 45 mL/min/1.73 m2, the positive likelihood ratios （ ＋ LR） were 9.3, 30. 1, and 13 and the odds ratio （OR） were 21.1, 68.4 and 39.4, respectively, which reached satisfactory diagnostic performance. As eGFR-SCr/CysC cut- off point at 60 mL/min/1.73 m2 with ＋ LR at 30. 1 and OR at 68.4, eGFR-SCr/CysC equation bad the best diagnostic performance. The negative likelihood ratios （ - LR） interval was 0.33 - O. 49, which had no value for diagnosis of chronic kidney disease （CKD）. The diagnostic performance of eGFR-CysC equation was slightly better than eGFR-SCr equation. When the cut-off point was 60 mL/min/1.73 m2, both the ＋ LR and OR of eGFR-CysC and eGFR-SCr/CysC equations were the highest （20.8, 94.5, respectively）, which were also helpful to confirm diagnosis of CKD. The combined-LRs （0. 12 - 0.22） of eGFR were lower than separate-LRs （0. 33 - 0.49） of eGFR, so the combined-LRs increased the ability of excluding diagnosis of CKD. Conclusion For evaluating the renal damage clinically, the eGFR-SCr/CysC equation is more accurate than the equation of SCr or CysC alone.