Does size matter? Kidney transplant donor size determines kidney function among living donors

Abstract

BackgroundKidney donor outcomes are gaining attention, particularly as donor eligibility criteria continue to expand. Kidney size, a useful predictor of recipient kidney function, also likely correlates with donor outcomes. Although donor evaluation includes donor kidney size measurements, the association between kidney size and outcomes are poorly defined.MethodsWe examined the relationship between kidney size (body surface area-adjusted total volume, cortical volume and length) and renal outcomes (post-operative recovery and longer-term kidney function) among 85 kidney donors using general linear models and time-to-chronic kidney disease data.ResultsDonors with the largest adjusted cortical volume were more likely to achieve an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 over a median 24-month follow-up than those with smaller cortical volumes (P <0.001), had a shorter duration of renal recovery (1.3–2.2 versus 32.5 days) and started with a higher eGFR at pre-donation (107–110 versus 91 mL/min/1.73 m2) and immediately post-nephrectomy (∼63 versus 50–51 mL/min/1.73 m2). Similar findings were seen with adjusted total volume and length.ConclusionsLarger kidney donors were more likely to achieve an eGFR ≥60 mL/min/1.73 m2 with renal recovery over a shorter duration due to higher pre-donation and initial post-nephrectomy eGFRs.

Remaining kidney volume indexed to weight as a strong predictor of estimated glomerular filtration rate at 1 year and mid‐term renal function after living‐donor nephrectomy ‐ a retrospective observational study

“…Predonation eGFR is one of the strongest predictors of 1‐year postdonation renal function [24], and we showed that the predonation eGFR had a linear independent positive correlation with 1‐year eGFR (each increase of 14 ml/min/1,73 m 2 in baseline eGFR decreased the risk of having eGFR < 60 ml/min/1,73 m 2 one year after donation by 69%) agreeing with these studies. Living‐donor's population is composed by very healthy individuals: young (mean 48 years), low BMI (mean 25 kg/m 2 ), and good predonation eGFR (mean 100 ml/min/1.73 m 2 ) [25].…”

Baseline living‐donor kidney volume and function associate with 1‐year post‐nephrectomy kidney function

“…The researchers did not, however, report associations based on remaining kidney function. Narasimhamurthy et al evaluated 85 donors and found those with larger combined kidney volumes adjusted for BSA were more likely and more quickly to achieve eGFR values of 60 mL/min/1.73 m 2 or more, but the researchers did not report associations for remaining kidney volume nor did they adjust for baseline eGFR or other donor factors. In a French cohort of 105 donors, Gardan et al found that the unadjusted cortical volume of the remaining kidney predicted measured GFR <60 mL/min/1.73 m 2 at 1 year with an area under the receiver‐operating characteristic curve of 0.80 .…”

Effect of recipient-donor sex and weight mismatch on graft survival after deceased donor renal transplantation

“…Among them, donor/recipient size and sex mismatch have been identified as possible risk factors for impaired graft survival. Several studies have focused either on kidney weight [5], body mass index (BMI) [6], or body surface area (BSA) [7] as estimates of transplanted nephron mass after deceased-donor transplantation as well as after living donation [8]. Sex mismatch has also been associated with reduced graft function, but findings on this topic have been inconsistent [9].…”