The equation developed from the MDRD (Modification of Diet in Renal Disease) study provides more accurate estimate of GFR than other commonly used equations. The aim of this study was to compare prediction of GFR based on MDRD and Cockcrof-Gault (CG) method. The study was performed in 111 patients (mean age 42 ± 5 years) with chronic renal impairment (Scr = 281 ± 83
mol/l). The mean of MDRD was 0.480 ± 0.345 ml/s/1.73 m2 and that of CG 0.608 ± 0.336 ml/s/1.73 m2. The difference is highly significant (p < 0.0001). The mean of CG/MDRD ratio was 1.24 ± 0.17. This ratio was significantly higher (p < 0.01) in obese patients (1.59 ± 0.14 vs 1.22 ± 0.09). The CG/MDRD ratio did not show relation to Scr. The results are in keeping with the assumption that the difference between MDRD and CG method cannot be explained by increased tubular secretion of creatinine in residual nephrons. Obesity seems to be on of the factors responsible for the difference between CG and MDRD values.

        Key words: Glomerular filtration - Creatinine serum concentration - MDRD