van Londen M, et al. - Whether post-donation estimated glomerular filtration rate (eGFR) slopes vs measured GFR (mGFR) slopes can afford precise and accurate measures for long-term follow-up of renal function after kidney donation, was investigated. Researchers found that in donors with a declining GFR between 3 months and 5 years post-donation, GFR slopes were underestimated by all eGFR equations. The value of mGFR in the follow-up of donors with risk of progressive GFR loss was emphasized in this study.

Methods

• This study included 349 donors (age 51 ± 10, 54% female).
• Researchers analysed study participants for eGFR according to the 2009 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, Modification of Diet in Renal Disease (MDRD) and Cockcroft–Gault/body surface area (CG/BSA), creatinine clearance (CrCl) and mGFR (¹²⁵I-iothalamate) changes from 3 months until 5 years post-donation.

Results

• A pre-donation mGFR of 116 ± 23 mL/min was detected in donors.
• Data showed 73 ± 14 mL/min to be the mGFR at 3 months post-donation and at 5 years it was 79 ± 16 mL/min.
• A declining mGFR (-0.82 ± 0.79 mL/min/year) was found in 28% of donors between 3 months and 5 years post-donation, 47% were stable and 25% had an increasing mGFR.
• Researchers found eGFR equations demonstrated good slope estimates (bias eGFR_CKD-EPI 0.13 ± 2.16 mL/min/year, eGFR_MDRD 0.19 ± 2.10 mL/min/year, eGFR_CG/BSA -0.08 ± 2.06 mL/min/year, CrCl -0.12 ± 4.75 mL/min/year),
• They also observed underestimation of the slope in donors with a decreasing mGFR (bias eGFR_CKD-EPI 1.41 ± 2.03 mL/min/year, eGFR_MDRD 1.51 ± 1.96 mL/min/year, eGFR_CG/BSA 1.20 ± 1.87 mL/min/year).
• Data revealed CrCl had a high imprecision [bias interquartile range -1.51–3.41 mL/min/year].