The serum cystain C-based equation is more accurateto estimate the glomerular filtrations rate in Chinese adults than the serum creatinine-based equation

Objective To compare the performances of the serum cystain C-based equation and the serum creatinine-based equation in Chinese adults.Methods The clinical data of 623 patients with chronic kidney disease(CKD)at Zhongnan Hospital of Wuhan University(Wuhan,China)from July 1,2017 to July 31,2019 were analyzed.It was taken as the gold standard to calculate eGFR with the Gates method after ^99mTc-DTPA isotope kidney imaging.The eGFR values were calculated,using the CKD-EPI_Scr,CKD-EPI_ScysC,FAS_Scr,FAS_ScysC equations,based on Scr and Scys C values within 48 hours before the isotope kidney imaging.Then,bias,precision and accuracy of the eGFR values from mGFR values were compared between various equations.In accordance with the 2012 KDIGO guidance,the CKD staging was performed with the mGFR values,and compliance of the eGFR with the mGFR staging results was analyzed.Results The ScysC-based equation had less bias and higher accuracy than the Scr-based equation in the overall sample and renal injury and age subgroups.In the overall group,the bias of CKD-EPI_ScysCvs CKD-EPI_Scrwas-4.65 vs-10.67,P30 was 56.7% vs 48.8%;the FAS_ScysCvs FAS_Scr bias was-7.49 vs-10.16 and P30 was 56.0% vs 51.4%.In the moderate to severe renal injury group,the bias of CKD-EPI_ScysCvs CKD-EPI_Scr was-2.23 vs-7.14,P30 was 57.4% vs 45.5%;the FAS_ScysCvs FAS_Scr bias was-6.69 vs-7.14 and P30 was 53.0% vs 48.2%.In the elderly group(age≥70),the bias of CKD-EPI_ScysCvs CKD-EPI_Scr was-2.23 vs-9.13,P30 was 59.4% vs 41.3%;the FAS_ScysCvs FAS_Scr bias was-5.78 vs-6.12 and P30 was 53.8% vs 51.0%.The ScysC-based equation was more accurate than the Scr-based equation in the diagnosis of CKD wih eGFR and mGFR values calculated with various equations.The areas under the ROC curve of the CKD-EPI_Scr,CKD-EPI_ScysC,FAS_Scr and FAS_ScysC were 0.935,0.938,0.936,and 0.937,respectively.Their kappa values were 0.264,0.331,0.301 and 0.315,respectively.Conclusions The solo ScysC-based equation is more accurate than the solo Scr-based equation to estimate the eGFR in Chinese adults.