Clinical Decision Making in a Patient with Stage 5 CKD--Is eGFR Good Enough?

Abstract

The development and widespread use of serum creatinine concentration-based prediction equations to calculate eGFR have been major advances for detection of patients with CKD and the epidemiologic study of CKD and its outcomes. However, these equations as well as those that also incorporate serum cystatin C concentration provide GFR estimates that, although reasonably precise on average, can differ markedly and in clinically important ways from actual GFR. Thus, it is important that clinicians who use these equations for clinical decision-making be familiar with their strengths and weaknesses and have an appreciation of their potential for error. More precise knowledge of actual GFR is important in certain clinical circumstances, including, as presented in this Attending Rounds, patients with stage 5 CKD, in whom decisions regarding dialysis initiation are necessary. Nephrologists should have the ability to accurately determine GFR when needed if clinical circumstances suggest inaccuracy of the calculated eGFR reported by the clinical laboratory.

Keywords: CKD; Cockcroft–Gault; ESRD; GFR.

Figure 1.

Significant differences exist between mGFR and eGFR with both the MDRD and CKD Epidemiology Collaborative equations. Comparison of eGFR using (A) the MDRD and (B) the CKD Epidemiology Collaboration equations compared with mGFR (iothalamate). MDRD, Modification of Diet in Renal Disease; mGFR, measured GFR. Reference .

Figure 2.

Difference between mGFR and eGFR (MDRD equation) from the combined dataset derived from 10 studies. mGFR, measured GFR; MDRD, Modification of Diet in Renal Disease. Reprinted from reference , with permission.