Longitudinal Trajectories of Estimated Glomerular Filtration Rate in a European Population of Living Kidney Donors

A living donor (LD) kidney transplant is the best treatment for kidney failure, but LDs safety is paramount. We sought to evaluate our LDs cohort's longitudinal changes in estimated glomerular filtration rate (eGFR). We retrospectively studied 320 LDs submitted to nephrectomy between 1998 and 2020. The primary outcome was the eGFR change until 15 years (y) post-donation. Subgroup analysis considered distinct donor characteristics and kidney function reduction rate (%KFRR) post-donation [-(eGFR_{6 months(M)}-eGFR_pre-donation)/eGFR_pre-donation*100]. Donors had a mean age of 47.3 ± 10.5 years, 71% female. Overall, LDs presented an average eGFR change 6 M onward of +0.35 mL/min/1.73 m²/year. The period with the highest increase was 6 M-2 Y, with a mean eGFR change of +0.85L/min/1.73 m²/year. Recovery plateaued at 10 years. Normal weight donors presented significantly better recovery of eGFR +0.59 mL/min/1.73 m²/year, compared to obese donors -0.18L/min/1.73 m²/year (p = 0.020). Noteworthy, these results only hold for the first 5 years. The subgroup with a lower KFRR (<26.2%) had a significantly higher decrease in eGFR overall of -0.21 mL/min/1.73 m²/year compared to the groups with higher KFRR (p < 0.001). These differences only hold for 6 M-2 Y. Moreover, an eGFR<50 mL/min/1.73 m² was a rare event, with ≤5% prevalence in the 2-15 Y span, correlating with eGFR pre-donation. Our data show that eGFR recovery is significant and may last until 10 years post-donation. However, some subgroups presented more ominous kidney function trajectories.