Impact of measured versus estimated glomerular filtration rate-based screening on living kidney donor characteristics: A study of multiple cohorts.

BACKGROUND: Most transplant centers in the Netherlands use estimated glomerular filtration rate (eGFR) for evaluation of potential living kidney donors. Whereas eGFR often underestimates GFR, especially in healthy donors, measured GFR (mGFR) allows more precise kidney function assessment, and therefore holds potential to increase the living donor pool. We hypothesized that mGFR-based donor screening leads to acceptance of donors with lower pre-donation eGFR than eGFR-based screening. METHODS: In this longitudinal cohort study, we compared eGFR (CKD-EPI) before donation in one center using mGFR-based screening (mGFR-cohort, n = 250) with two centers using eGFR-based screening (eGFR-cohort1, n = 466 and eGFR-cohort2, n = 160). We also compared differences in eGFR at five years after donation. RESULTS: Donor age was similar among the cohorts (mean±standard deviation (SD) mGFR-cohort 53±10 years, eGFR-cohort1 52±13 years, P = 0.16 vs. mGFR-cohort, and eGFR-cohort2 53±9 years, P = 0.61 vs. mGFR-cohort). Estimated GFR underestimated mGFR by 10±12 mL/min/1.73m2 (mean±SD), with more underestimation in younger donors. In the overall cohorts, mean±SD pre-donation eGFR was lower in the mGFR-cohort (91±13 mL/min/1.73m2) than in eGFR-cohort1 (93±15 mL/min/1.73m2, P<0.05) and eGFR-cohort2 (94±12 mL/min/1.73m2, P<0.05). However, these differences disappeared when focusing on more recent years, which can be explained by acceptance of more older donors with lower pre-donation eGFR over time in both eGFR-cohorts. Five years post-donation, mean±SD eGFR was similar among the centers (mGFR-cohort 62±12 mL/min/1.73m2, eGFR-cohort1 61±14 mL/min/1.73m2, eGFR-cohort2 62±11 mL/min/1.73m2, P = 0.76 and 0.95 vs. mGFR-cohort respectively). In the mGFR-cohort, 38 (22%) donors were excluded from donation due to insufficient mGFR with mean±SD mGFR of 71±9 mL/min/1.73m2. CONCLUSIONS: Despite the known underestimation of mGFR by eGFR, we did not show that the routine use of mGFR in donor screening leads to inclusion of donors with a lower pre-donation eGFR. Therefore eGFR-based screening will be sufficient for the majority of the donors. Future studies should investigate whether there is a group (e.g. young donors with insufficient eGFR) that might benefit from confirmatory mGFR testing.

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.

To establish the outcome of live kidney donors 5 years after donation, we investigated the risk for progressive renal function decline and quality of life (QoL). Data on estimated glomerular filtration rate (eGFR), creatinine, hypertension, QoL and survival were assessed in a prospective cohort of 190 donors, who donated between 2008 and 2010. Data were available for >90%. The mean age predonation was 52.8 ± 11.5 years, 30 donors having pre-existent hypertension. The mean follow-up was 5.1 ± 0.9 years. Eight donors had died due to non-donation-related causes. After 5 years, the mean eGFR was 60.2 (95% CI 58.7-62.7) ml/min/1.73 m2 , with a median serum creatinine of 105.1 (95% CI 102.5-107.8) µmol/l. eGFR decreased to 33.6% and was longitudinally lower among men than women and declining with age (P < 0.001), without any association on QoL. Donors with pre-existent and new-onset hypertension demonstrated no progressive decline of renal function overtime compared to nonhypertensives. No donors were found with proteinuria, microalbuminuria or at risk for end-stage renal disease. After an initial decline postdonation, renal function remained unchanged overtime. Men and ageing seem to affect renal function overtime, while decreased renal function did not affect QoL. These data support further stimulation of living kidney donation programmes as seen from the perspective of donor safety.

More than a decade after live donor nephrectomy: a prospective cohort study.

Previously reported short-term results after live kidney donation show no negative consequences for the donor. The incidence of new-onset morbidity takes years to emerge, making it highly likely that this will be missed during short-term follow-up. Therefore, evidence on long-term outcome is essential. A 10-year follow-up on renal function, hypertension, quality of life (QOL), fatigue, and survival was performed of a prospective cohort of 100 donors. After a median follow-up time of 10 years, clinical data were available for 97 donors and QOL data for 74 donors. Nine donors died during follow-up of unrelated causes to donation, and one donor was lost to follow-up. There was a significant decrease in kidney function of 12.9 ml/min (P < 0.001) at follow-up. QOL showed significant clinically relevant decreases of 10-year follow-up scores in SF-36 dimensions of physical function (P < 0.001), bodily pain (P = 0.001), and general health (P < 0.001). MFI-20 scores were significantly higher for general fatigue (P < 0.001), physical fatigue (P < 0.001), reduced activity (P = 0.019), and reduced motivation (P = 0.030). New-onset hypertension was present in 25.6% of the donors. Donor outcomes are excellent 10 years post-donation. Kidney function appears stable, and hypertension does not seem to occur more frequently compared to the general population.