No evidence of accelerated loss of kidney function in living kidney donors: results from a cross-sectional follow-up

BACKGROUND: There is a lack of kidneys available for kidney transplantation, and living donors are increasingly used. It is important to examine the possible long-term adverse affect on the renal function and blood pressure of the donors. METHODS: We have made a comprehensive follow-up of all living kidney donors at our center from 1964 to 1995. Of 402 donors still alive, we were able to get information about serum creatinine, urinary proteins, and blood cells in urine using reagent strips, and blood pressure from 87%. The glomerular filtration rate (GFR) was estimated using a formula and was measured with Iohexol clearance in 43 of the donors. Individual data on GFR and the prevalence of hypertension were compared with the age- and gender-expected values. RESULTS: The mean age of the examined donors was 61 years (SD:13) at follow-up, and the time since donation was 12 years (SD:8). The average estimated GFR was 72% (SD:18) of the age-predicted value. The ratio of the estimated to the predicted GFR showed no correlation to the time since donation, indicating that there is no accelerated loss of renal function after donation. GFR below 30 ml/min was found in five donors. No donor died in uremia or had dialysis treatment before death. However, three donors developed renal disease, and one was in dialysis treatment. In two of these cases, hereditary factors were possibly involved. Hypertension was present in 38% of the donors but the age-adjusted prevalence of hypertension among donors was not higher than in the general population. Significant proteinuria (> or =1.0 g/L) was found in 3% and slight proteinuria (<1.0 g/L) in 9% of the donors. Proteinuria was associated with hypertension and a lower GFR. CONCLUSIONS: On average, the remaining renal function of kidney donors did not deteriorate more rapidly than what may be expected from ageing. However one-third of the female and half of the male donors developed hypertension and, approximately, 10% displayed proteinuria. Nevertheless, our study supports the continued use of living kidney donors if strict criteria are used for acceptance.