Determination of Lowest Possible Creatinine in Living-Donor Kidney Renal Transplant Recipients Based on Donor Kidney Function

Abstract

The objective of this study was to use information from a donor to establish the lowest possible serum creatinine (SCr) of the recipient as a means of identifying early graft dysfunction. We analyzed retrospectively 58 pairs of living donors and recipients. The lowest possible SCr was calculated from four different formulae derived from Cockcroft-Gault formula: Ax(140-recipient age)xrecipient weight/donor GFR (A, women: 1.04, men: 1.23). Donor GFR was represented by the following values (a) mSCrD0: measured pretransplant GFR for both kidneys, (b) mSCrSKD0: single transplanted kidney GFR on day 0, (c) eSCrD0: estimated GFR based on SCr at day 0, or (d) eSCrD30: on day 30. These resulting estimated SCr were tested for correlation coefficient, bias, precision, and accuracy in predicting the lowest observed recipient SCr during the first year posttransplant. The lowest possible SCr was 80+/-22 micromol/L for mSCrD0, 79.1+/-23 micromol/L for mSCrSKD0, 83+/-27 micromol/L for eSCrD0, and 115+/-22 micromol/L for eSCrD30. Mean values for lowest possible SCr correlated significantly with the lowest observed SCr for all four formulae. The eSCrD0 formula showed the best correlation (r=0.47), the smallest positive bias (20.5 micromol/L), the highest precision (21.9 micromol/L), and the second highest percentage of predicted values that fell within 30% of the observed SCr (69%). The use of the Cockcroft-Gault derived formula with eSCrD0 may be a useful tool to detect early discrepancy between observed and lowest possible SCr value. This could help to identify patients who may require invasive investigations.