Assessing renal graft function in clinical trials: can tests predicting glomerular filtration rate substitute for a...

Area of Science:

• Nephrology
• Clinical Trials
• Renal Transplantation

Background:

• Accurate assessment of renal graft function is vital in clinical trials.
• Reference methods for glomerular filtration rate (GFR) determination are often impractical.
• The validity of commonly used GFR estimation tests in renal transplant recipients is not well-established.

Purpose of the Study:

• To compare the performance of six different GFR estimation formulas against inulin clearance in renal transplant patients.
• To evaluate the accuracy and agreement of these GFR tests in this specific population.

Main Methods:

• Retrospective analysis of 500 inulin clearances from 294 renal transplant recipients with stable renal function.
• Calculation of six GFR estimates: 24-hour creatinine clearance, Cockcroft-Gault, Walser, Jelliffe, Nankivell, and Levey formulas.
• Assessment of performance using correlation, accuracy (error dispersion), and agreement (Bland-Altman analysis).

Main Results:

• All tested GFR formulas showed significant correlation with inulin clearance (P < 0.0001).
• Levey, Jelliffe, and Walser formulas exhibited comparable accuracy and lower dispersion than others.
• However, all formulas demonstrated poor agreement with inulin clearance, with wide limits of agreement (>40 mL/min/1.73 m2).

Conclusions:

• No tested GFR estimation formula can reliably replace inulin clearance in renal transplant recipients.
• Reference methods for GFR measurement are recommended for assessing renal graft function in clinical trials.