The Effect of Donors' Demographic Characteristics in Renal Function Post-Living Kidney Donation. Analysis of a UK Single Centre Cohort

Abstract

Introduction: There is a great need to increase the organ donor pool, particularly for living donors. This study analyses the difference in post-living donation kidney function according to pre-donation characteristics of age, genetic relationship with the recipient, sex, ethnicity, and Body Mass Index (BMI).

Methods: Retrospective single centre analysis of the trajectory of estimated Glomerular Filtration Rate (eGFR) post-living kidney donation, as a measure of kidney function. Mean eGFR of the different groups was compared at 6 months and during the 60 months follow up.

Results: Mean age was 46 ± 13 years, 57% were female, and 60% Caucasian. Mean BMI was 27 ± 5 kg/m², with more than a quarter of the cohort having a BMI > 30 (26%), and the majority of the donors genetically related to their recipients (56%). The higher decline rate in eGFR was at 6 months after donation, with female sex, non-Caucasian ethnicity, and age lower than 60 years being independently associated with higher recovery in kidney function (p < 0.05). In the 60 months follow up, older age, genetic relationship with the recipient, and male sex led to higher percentual difference in eGFR post-donation.

Conclusion: In this study, with a high proportion of high BMI living kidney donors, female sex, age lower than 60 years, and non-genetic relationship with recipient were persistently associated with higher increase in post-donation kidney function. Ethnicity and BMI, per se, should not be a barrier to increasing the living donor kidney pool.

Keywords: age; ethnicity; genetic relationship donor/recipient; kidney transplantation; living donor; obesity.

Figure 1

General Linear Model of Repeated Measures ANOVA of mean eGFR (Figure 1A) and mean Δ eGFR (Figure 1B) during the 60 months follow up. There is a decline in eGFR post-donation, with a statistical significant correlation with age > 60 years (p < 0.001). The percentual difference in eGFR is also statistically different, with lower recovery for age > 60 years (p = 0.037).

Figure 2

General Linear Model of Repeated Measures ANOVA of mean eGFR (Figure 2A) and mean Δ eGFR (Figure 2B) during the 60 months follow up. There is no difference in mean eGFR post-donation according to the genetic relationship with the recipient (p = 0.168), while the percentual recovery in eGFR is statistically different, being higher for live unrelated donor (p = 0.007). LRD: Living Related Donor; LURD: Living Unrelated Donor.

Figure 3

General Linear Model of Repeated Measures ANOVA of mean eGFR (Figure 3A) and mean Δ eGFR (Figure 3B) during the 60 months follow up. Mean eGFR at donation is lower in females (p < 0.001), but in the 60 months follow up mean eGFR is no longer significant (p = 0.3), because the mean percentual difference in eGFR is higher in males (p < 0.001).

Figure 4

General Linear Model of Repeated Measures ANOVA of mean eGFR (Figure 4A) and mean Δ eGFR (Figure 4B) during the 60 months follow up. The mean eGFR post-donation does not differ according to BMI (p = 0.53), with no difference also in kidney function recovery after live donation (p = 0.79).

Figure 5

General Linear Model of Repeated Measures ANOVA of mean eGFR (Figure 5A) and mean Δ eGFR (Figure 5B) during the 60 months follow up. The mean eGFR post-donation confirmed to be lower for Caucasian ethnicity (p < 0.001), as well as the recovery in kidney function at 6 months (p = 0.035). There is not a statistically significance difference in the general linear model for the Δ eGFR at 60 months follow up (p = 0.38).