In renal transplantation, GFR decline is strongly associated to graft failure and patient death and thus could be an interesting proxy for clinical research. GFR estimating equations are known to underestimate GFR decline. Consequently, the threshold usually retained for the GFR decline is very high, around 50% (corresponding to a doubling in serum creatinine). Such a decline is a rare and delayed event limiting its relevance as a criterion of judgment. A decline of 30% has recently been proposed as an acceptable alternative in CKD patients with native kidneys. We aimed at evaluating the validity of the 30% threshold in renal transplantation and the ability of the CKD-EPI equation to detect this threshold.

Monocentric analysis of patients transplanted from 1989 to 2000 with a functioning graft 5 years post-tx and an evaluation of GFR with inulin and CKD-EPI equation available at 1 and 5 years post-tx. Association between GFR decline and graft failure and patient death was analysed with a competing-risk COX model.

Out of the 416 analysed patients, 156 lost their graft and 135 died during the follow-up. At the 30%-threshold of GFR decline, concordance between inuline and CKD-EPI was 53%. Association between GFR-inulin decline and graft failure remained significant regardless of the considered threshold (HR of 2.5 [1.6-3.8] and of 5.8 [3.4-10.0] for a threshold of 30 and 50%, respectively). A CKD-EPI-decline of 30% was similarly associated to graft failure (HR de 3.1 [1.9-4.9]). Similar results were observed for patient death.

A GFR decline of 30% between 1 and 5 years post-tx might be a valid surrogate for long term outcome in renal transplantation. Despite a poor concordance between inulin and CKD-EPI, utilization of CKD-EPI equation does not seem to impair the association between GFR decline and graft/patient survival.

CITATION INFORMATION: Delay A, Moranne O, Maillard N, Alamartine E, Mariat C. Association Between GFR Decline and Long Term Outcome in Renal Transplantation. Am J Transplant. 2016;16 (suppl 3).

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