The Value Of The Glomerular Filtration Rate In Esitmating Diabetic With Chronic Kidney Disease Patients’ Renal Function

Objective: To evaluate the application of Cockcroft-Gault formula, simplified MDRDequation, and Chinese MDRD equation and the Ruijin equation in elderly Chinesepatients with diabetes mellitus（DM）and chronic kidney disease（CKD）.To investigatethe influence of blood glucose level on the estimated glomerular filtration rate（eGFR）byCockcroft-Gault（CG） and Ruijin formula in DM, and to explore the difference betweenCG and Ruijin formula to estimate GFR in different level of glucose in the diagnosis ofmoderate renal insufficiency.Methods: Atotal of126elderly DM patients were investigated in294diabetic patients.GFR was estimated with Cockcroft-Gault formula，simplified MDRD equation，ChineseMDRD equation and the Ruijin equation. A total of294diabetic patients were enrolledin this study. HbA1c,Scr and standard GFR（sGFR）（99mTc-DTPA） were measured.Ruijin and CG formula were used to estimate the GFR（eGFR瑞金，eGFRCG）. The patientswere divided into normal GFR group[NGFR, n=123，sGFR≥90ml·min^-1·（1.73m2）^-1]，gently decreased GFR group[GGFR，n=113，60≤sGFR<90ml·min^-1·（1.73m2）^-1]，moderate decreased GFR group [MGFR，n=48，30≤sGFR<60ml·min^-1·（1.73m2）^-1], andsever decreased GFR group [SGFR,n=10,sGFR＜30ml·min^-1·（1.73m2）^-1]based on theK/DOQI suggestion．According to the quartile HbA1c level（7.0%，9.4%），patients weredivided into four groups. Patients with HbA1c＜7.0%were defined as well-controlledgroup, with HbA1c≥9.4%as poorly-controlled group．Spearman correlation，t test，Bland-Altman analysis and ROC curve were applied to investigate the bias and accuracy of formula，and the influence of blood glucose on eGFR．Results:（1） Bland-Altman analysis demonstrated that Ruijin equation was moreconsistent with sGFR than the other equations. However, all equations were not wellconsistent with sGFR. Linear regressions showed that the slope of the Ruijin equationwas closer to the identical line.The15%，30%，50%accuracies of Ruijin equation werehigher than those of the other equations,but the30%accuracy of Cockcroft-Gaultformula，simplified MDRD equation，Chinese MDRD equation were still less than70%，only the30%accuracy of Ruijin equation was70.6%.（2） HbA1c was correlatedwith sGFR （r=0.188,P＜0.01），eGFRCG（r=0.234,P＜0.01），eGFR瑞（金r=0.245,P＜0.01）.eGFR瑞金seemed to overestimate GFR in gently and moderate decreased GFR group.However, eGFRCGseemed to overestimate GFR except in sever decreased GFR group.Bland-Altman analysis indicated that the bias of eGFR瑞金with sGFR inpoorly-controlled group was higher than that in well-controlled group.Compared withpoorly-controlled group, the30%accuracies of eGFR瑞金in well-controlled group weresignificantly higher. The bias of eGFRCGwith sGFR in poorly-controlled group washigher than that in well-controlled group. Compared with poorly-controlled group, the30%,50%accuracies of eGFRCGin well-controlled group were significantly higher.there was no significant difference between eGFRCGand eGFR瑞金in well-controlledgroup；compared with eGFRCG, the30%,50%accuracies of eGFR瑞金were significantlyhigher. In poorly-controlled group，the bias of eGFRCGwas higher than eGFR瑞金；the30%,50%accuracies of eGFR瑞金were significantly higher than eGFRCG. The areaunder ROC curve was no significant difference in eGFRCGand eGFR瑞金inpoorly-controlled group and well-controlled group.Conclusion： Compared with the reference standard, four equations show a lowerdegree of accuracy.The Ruijin equation shows a little better than other equations in elderly Chinese patients with diabetes mellitus. GFR by Ruijin and CG formula indiabetic patients may lead to discrepancies with GFR value.eGFRCGand eGFR瑞金overestimate the GFR value. CG and Ruijin formula are similarly accurate and robust inpoorly-controlled and well-controlled diabetic patients with moderate renalinsufficiency.