What is the Best Formula to Estimate GFR in Renal Allograft? Presenter: Ammar Qutub Supervisor: Prof.Abdallah Sayyari KSAU-HS College of Medicine

Background Serum creatinine is unreliable in assessing renal transplant function Conflicting data on the performance of different GFR formulae “Gold Standards” are expensive and cumbersome

The Most Widely Used Formulae In native kidneys Modification of diet in renal disease (MDRD) Cockcroft-Gault (CG) In transplant kidneys The Nankivell formula SCr measurement in these formulae was not calibrated

Literature Search None of the equations were suitable. Poggio et al 2006, the performance of the MDRD superior to the Nankivell and C-G formulae. Gaspari et al 2004, superiority of MDRD and Nankivell over C-G.

Objective of the Study To assess the performance and accuracy of various GFR formulae in estimating the renal function of renal allograft

Methods 71 Blood samples Mean 5.2 years Enzymatic determination SCr Calcineurin inhibitors Measured GFR Tc 99m-DTPA isotope (reference standard) Estimated GFR by MDRD, C-G and NK formulae In addition GFR was calculated using Cystatin C

Data Analysis Data are presented as mean and standard deviation Bias was calculated as the difference between the mean of estimated and measured GFR Precision was calculated as the correlation coefficient for estimated and measured GFR

Descriptive dataMeanStdMale49% Age BMI Serum Creatinine GFR_isotope Cystatin C 5623 MDRD5915 Nankivell C-G C-G

Bias MDRDCystatin CNankivellC-G Bias P value % Bias2.6%2.4%12.3%20.9%

Precision Cystatin CMDRDNankivellC-G Precision p value

Our study bias vs Poggio et al(2006) Our studyPoggio et al MDRD Nankivell C-G

Correlation Between DTPA & Cystatin C (r=0.612, P<0.0001)

Correlation between DTPA & MDRD (r=0.490, P<0.0001)

Correlation Between DTPA & Nankivell (r=0.316, P<0.007)

Correlation Between DTPA & C-G (r=0.072, P<0.551)

Conclusion Nankivell & C-G showed the least correlation and biggest bias, 12.3% & 20.9% respectively in renal transplant Best correlation and least bias was seen with Cystatin C and MDRD formulae (2.4% & 2.6%)

Thank You