Transpl Int. 2017 Mar;30(3):266-276. doi: 10.1111/tri.12872.

Five-year follow-up after live donor nephrectomy – cross-sectional and longitudinal analysis of a prospective cohort within the era of extended donor eligibility criteria.

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Living kidney donors are selected according to the Amsterdam forum donor eligibility acceptance criteria [1] and probably will have a lower risk for cardiovascular disease, kidney-related morbidity or end-stage renal disease during follow-up. However, life style may influence and dominate outcome and donors may have a disadvantage as renal reserve to compensate for loss of kidney function is reduced due to donation. As the development of cardiovascular disease or chronic kidney disease takes years, short-term follow-up studies might underreport these consequences. Therefore, long-term studies are necessary to define the safety boundaries of live kidney donation.

 

We have studied outcomes five years after donation in a prospective cohorts of 190 donors included between 2009-2011 in a randomized controlled trial comparing different surgical techniques. In this study donors with extended eligibility acceptance criteria were included, proteinuria and microalbuminuria were measured, kidney function decline registered, and kidney function compared to a selection of non-donors derived from the general population. In addition, longitudinal analyses were included on kidney function and quality of life to evaluate the effect of extended eligibility acceptance criteria, such as higher age, higher BMI and the prevalence or incidence of hypertension, and to evaluate if donors were at risk for a progressive decline in kidney function.

 

This study demonstrated that kidney function initially declined after donation as might be expected, restored somewhat in the months thereafter and stabilized at a level identical to the one-year follow up measurement. Thereafter, the kidney function remained stable. The overall eGFR decline was 34% after five years. The additional analyses demonstrated that donors had a kidney function within the lower range of matched age-categories of a population-based reference group. Furthermore, there was no different outcome in eGFR or eGFR decline in donors with extended eligibility criteria. In addition, we demonstrated that no proteinuria or microalbuminuria was observed in any of the donors, not even in donors with an eGFR <60 ml/min/1.73 m2. Donors with an eGFR <60 ml/min/1.73m2 were significantly older at the time of donation, had a lower pre-donation kidney, and a higher eGFR decline function than donors with an eGFR ≥60 ml/min/1.73m2. Also, in longitudinal analyses of this study age and gender were associated with a decline in eGFR, whereas male gender was associated with a progressive decline in kidney function. None of the donors developed end-stage renal disease or required renal replacement therapy.

 

Donors who developed hypertension were significantly older at time of donation, with a higher BMI, and lower eGFR before donation when compared to donors who did not develop hypertension. Furthermore, this study demonstrated that there were more donors with an eGFR <60 ml/min/1.73m2 with new-onset hypertension compared to non-hypertensive donors. In addition, we found that donors with a pre-existent or new-onset hypertension did not have a progressive decline in kidney function. The kidney function of pre-existent hypertensive donors was not significantly different compared to non-hypertensive donors, while that of new-onset hypertensive donors was. However, the decline in kidney function of all these donors was not significantly different.

 

The quality of life scores of both studies were better or similar compared to general population scores, except for the mental component score in the second study. This was likely related to other life events than the donation. All quality of life scores significantly decreased at follow-up as might be expected from data derived from the general population. The overall decrease in all measures overtime is a phenomenon that has also been observed in the general population. In longitudinal analyses age and gender were associated with a decline in quality of life, which are known factors. Donors who have passed away during follow-up died due to non-donation related causes.

 

We have evaluated the current donor eligibility acceptance criteria of our own center by performing a longitudinal cohort study. The results are reassuring for the current practice of live kidney donation and the current live kidney donation program can safely proceed forward. Potential donors should not fear major negative changes at the long-term in this era of extended live kidney donation eligibility criteria. A conscientious follow-up of live kidney donors should be maintained after donation to evaluate any changes in health status.

 

References

1 Delmonico F: A Report of the Amsterdam Forum On the Care of the Live Kidney Donor: Data and Medical Guidelines. Transplantation 2005;79:S53-66.

 

Funding

The randomized controlled trial was financially supported by Medical Research Advising Committee, Erasmus MC, University Medical Center (Rotterdam, the

Netherlands) and Fonds NutsOhra. The current follow-up study was not financially supported.