Table 4.

Performances of the MDRD and CG formulas according to CKD classes in CKD patientsa

Measured GFR (ml/min per 1.73 m2)NMDRD Formula (ml/min per 1.73 m2)CG Formula (ml/min per 1.73 m2)
BiasPrecisionSensitivitySpecificityBiasPrecisionSensitivitySpecificity
≥90370−6.319.865.794.9−1.424.069.293.5
60–89526−1.015.562.786.10.215.959.785.9
30–595970.69.578.186.82.610.977.984.5
15–293122.37.278.993.94.98.067.692.8
<151282.45.164.899.35.25.343.099.5
• a CKD patients were divided into five categories, according to the GFR levels used to define the five stages of CKD in the K/DOQI CKD classification (5). Results obtained with these formulas were compared with GFR values obtained by measuring the renal clearance of 51Cr EDTA. Sensitivity and specificity of each formula for assigning patients to the K/DOQI categories of CKD as defined by GFR were also analyzed. Bias is defined as the mean difference between estimated and measured GFR. Precision is 1 SD of bias. Sensitivity is the percentage of well-classified patients within each CKD class. Specificity is the percentage of patients who do not belong to the CKD class of interest and are not classified in this category by the formula.