Background. The glomerular filtration rate (GFR) could be estimated on the basis of serum creatinine concentration
(Scr) and some simple variables and demographic data. In clinical practice the most used methods for GFR estimation
are Cockcroft – Gault (CG) formula and abbreviated MDRD equation (MDRD abr). The aim of this study was
to evaluate how far obesity could affect GFR estimation based on the above formulas.
Methods and Results. In 291 patients with chronic renal impairment (Scr 45–489 μmol/l) GFR was examined on the basis
of renal inulin clearance (Cin) and estimated using MDRD abr and CG (without correction for body surface area-BSA and
CG corrected for BSA) (CGkorig). The group of nonobese patients (A) consisted of 229 patients (BMI <30 kg/m2) and the
group of obese patients (B) consisted of 62 patients (BMI 30 kg/m2). The values of r (r2) for MDRD abr, CG and CGkorig in
group A of patients was as follows: 0.893 (0.797), 0.810 (0.651), 0.853 (0.727) and 0.853 (0.727). In obese patients (group
B) the corresponding values were as follows: 68.3 % (82.6 %), 28.6 % (39.7 %) and 46 % (61.9 %). Predicted GFR within
30 % and 50 % of Cin (in brackets), CG and CGkorig (for BSA) were for group A: 70.2 % (87.3 %), 50.4 % (67.1 %) and
55.7 % (75 %) and for group B: 68.3 % (82.6 %), 28.6 % (39.7 %) and 46 % (61.9 %). The ratio MDRD abr/Cin did not
correlate with BMI. A weak, but significant correlation was found between BMI and CCcorig/Cin ratio (r=0.22, p<0.05).
Conclusions. The obtained results suggest that estimation of GFR based on MDRD abr is not influenced by obesity.
Estimation of GFR based on CG formula is significantly affected by obesity. A weak but significant relation could by
found between CGkorig/Cin and BMI.
prediction glomerular filtration rate, MDRD, obesity.