Evaluation and comparison of various renal function tests in elderly patients with chronic kidney disease / 中华老年医学杂志

ABSTRACT

Objective To find out whether the levels of serum creatinine and urea,creatinine clearance rate and GFR estimated by using different equations correlate with the exact measurement of GFR with ~(99m)Tc-DTPA in elderly patients with chronic kidney disease.Methods Renal function was determined by using ~(99m)Tc-DTPA technique in 83 elderly patients aged 65—96 years.Blood and urine tests were done at the same time.Estimated clearance was determined by using the equations of Cockcroft-Gauh,MDRD(modification of diet in renal disease)predigestion and MDRD seventh,and the correlation coefficients between the above parameters and ~(99m)Tc-GFR were determined.Veracity for the diagnosis of renal dysfunction was calculated by using receiver operating characteristic(ROC) curves.Results Cockcroft-Gault formula(r=0.833),MDRD predigestion formula(r=0.811), MDRD seventh formula(r=0.803),creatinine(r=-0.672),Ccr(r=0.632),urea(r=-0.612), and albumin(r=0.444)were correlated significantly with ~(99m)Tc-GFR in this sequence.If GFR 30, 40,50,60ml/min were defined respectively as renal impairment thresholds and areas under the curve (AUC)were compared,the best parameter for estimation of GFR was the Cockcroft-Gault formula. Then MDRD predigestion formula and MDRD seventh formula,creatinine and Ccr were less accurate in all different renal dysfunction thresholds.Conclusions The Cockcroft-Gault equation seems to be the best formula available for GFR estimation,the two equations of MDRD are the second,creatinine is the third,Ccr and urea are the last.