Background: Increasing numbers of living donor kidney transplantations calls for better knowledge about long-term donor outcomes and risks.
Methods: To explore long-term kidney donor outcomes and risks, we conducted a cross sectional retrospective study. To this end, we analysed renal function using measured glomerular filtration rate (mGFR) and estimated glomerular filtration rate (eGFR) as well as microalbuminuria, blood pressure (BP), body mass index, haemoglobin, albumin and parathyroid hormone in kidney donors nephrectomized between 1965 and 2005.
Results: A total number of 573 kidney donors agreed to undergo medical follow-up examinations. The mean age (standard deviation) at donation was 47 (11) years and the mean time since donation was 14 (9) years. Both mean mGFR [68 (15) mL/min/1.73 m(2) body surface; P = 0.028] and mean eGFR [71 (16) mL/min/1.73 m(2) body surface; P < 0.001], based on modified diet renal dysfunction and iohexol or Cr-EDTA clearance, respectively, were found to decrease with age and to increase with time since donation. Special multivariable regression analyses reveal that for 30-year old donors, the median eGFR typically increases during the first 17 years, then remains constant for ~8 years and slowly declines thereafter. For 50-year-old donors, the median eGFR is expected to increase during the first 15 years or so and then to enter a phase of slight progressive decline. In total, 23% (126/546) of the donors were on antihypertensive medication. An additional 22% (117/543) of the donors were found to suffer from hitherto undiagnosed hypertension (BP >140/90 mm Hg).
Conclusion: Renal function of the remaining kidney in living donors is expected to improve for many years but will show signs of slight deterioration in the longer run.