[The application of glomerular filtration rate estimation equations in different stages of chronic kidney disease]

To understand the applicability of MDRD equation in Chinese patients with chronic kidney disease (CKD). Glomerular filtration rate (GFR) estimated with MDRD equation, abbreviated MDRD equation and Cockcroft-Gault equation was compared with (99m)Tc-DTPA plasma clearance by dual plasma sampling method in different stages of CKD.

CKD were diagnosed according to K/DOQI guideline.298 patients with CKD were selected. Patients'sex, age, height and body weight were recorded and plasma creatinine, urea nitrogen and albumin were measured in a single clinical laboratory. (99m)Tc-DTPA plasma clearance was calculated and standardized by body surface area (sGFR). GFRs estimated with MDRD equation 7, abbreviated MDRD equation and Cockcroft-Gault equation (7GFR, aGFR and cGFR) were compared with sGFR in different stages of CKD.

There were 165 male and 133 female in the selected 298 patients with CKD;the average age was (52.5 +/- 15.5) years. There was significant difference between the GFRs of the 3 equations with sGFR in different stages of CKD (P < 0.001). 7GFR, aGFR and cGFR were significantly higher than sGFR in CKD stages 5-4; the lower the sGFR, the more the differences. 7GFR, aGFR and cGFR were significantly lower than sGFR in CKD stage 2-1; the higher the sGFR, the more the differences.

Our results showed that in Chinese population with CKD, MDRD equation 7, abbreviated MDRD equation and Cockcroft-Gault equation overestimate actual GFR in CKD stages 4-5 and underestimate GFR in CKD stages 1-2. These results indicate that MDRD equation and its modifications for estimation of GFR should be amended when applying to Chinese patients with CKD in clinical practice.