Comparison of estimated and measured Glomerular Filtration Rate in Longitudinal Follow-up after Living Kidney Donation

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M. van Londen, J.S. Sanders, J.J. de Vries, M.F.C. de Jong, R.A. Pol, S.P. Berger, G.J Navis, M.H. de Borst

Chair(s): dr. M.A.C.J. Gelens

Thursday 9 march 2017

12:30 - 12:45h

Categories: Poster - Klinisch

Parallel session: Postersessie - Klinisch 4

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Donor safety requires reliable long term follow-­up of renal function after donation. We tested the longitudinal performance of estimated Glomerular Filtration Rate (eGFR) to detect renal function loss after donation by comparison with 125I-iothalamate measured GFR (mGFR), the gold standard.

We compared the slopes of MDRD, Cockcroft­Gault (CG) and CKD-­EPI equations with mGFR (125I-iothalamate) to assess renal function loss from 3 months after donation until 5 or 10 years after donation in 146 living kidney donors. We tested eGFR slopes for bias by tertiles of mGFR slopes.

At donation, donors (age 51(10) years, 53% male) had a median [IQR] mGFR of 103 [92;115] mL/min. After donation, mGFR was 65 [59;72], 66 [57;75] and 69 [61;77] mL/min at 3 months, 5 and 10 years, respectively. In donors with decreasing mGFR (n=59/146, slope -0.5 [-1.3;0.0] ml/min/yr), the slope was underestimated by all eGFR equations (CKD-EPI bias -2.4 [-3.8;-1.1] ml/min/1.73m2/yr, p<0.001; MDRD bias -2.6 [-3.7;-1.2] ml/min/1.73m2/yr, p<0.001; and CG/BSA bias -0.6 [-2.2;-0.3] ml/min/1.73m2/yr, p=0.02).

These data show that eGFR equations underestimate the slope of renal function in living donors with pronounced mGFR loss, underlining the value of mGFR in long term follow­-up.