Iohexol Clearance and Kidney Transplantation: Determinants of Its Variation in Living Kidney Donors One Year After Donation and Impact on Glomerular Filtration Rate Gain in Kidney Recipients.

BACKGROUND

Iohexol clearance (mGFRioh) is a marker of choice for measuring glomerular filtration rate (GFR) in potential living kidney donors.

OBJECTIVES

We studied (1) the determinants of mGFRioh variation among kidney donors before and 1 year after donation and (2) the impact of donor mGFRioh change on the gain in estimated GFR 3 months after transplantation in kidney transplant recipients.

METHODS

We performed a retrospective, monocentric study in couples of living kidney donors/transplant recipients. In donors, mGFRioh was measured before and 1 year after donation and calculated using the slope-intercept method and the Bröchner-Mortensen correction. In recipients, eGFR was calculated by the CKD-EPI formula before and 3 months after transplantation. Determinants of mGFRioh change in donors and eGFR change in recipients were studied using univariate and multivariate general linear models.

RESULTS

Sixty-nine kidney donors (41 women), with a median age of 56 years, were included. The median (10th-90th percentiles) decrease in mGFRioh at 1 year post-donation was 29.7% (13.9-43.0). Determinants of a greater mGFRioh decline (estimate; standard deviation) included female sex (-9.8; 3.3), older age (-0.43; 0.14), and high pre-donation mGFRioh value (-0.24; 0.07). Smoking status and body mass index were not associated with mGFRioh decrease. In kidney recipients, the gain in eGFRCKD-EPI at 3 months post-transplantation was not correlated to mGFRioh variation (before vs. 1 year post-donation) of donors.

CONCLUSIONS

Our data identified female sex and age as key determinants of mGFRioh at 1 year post-donation. Donor mGFRioh pre-donation or mGFRioh change 1 year after donation had no impact on early recipient kidney graft function.