Long-term follow-up of kidney donors : a longitudinal study

Kidney donors are not adversely affected by compensatory hyperfiltration of the remaining kidney in the early years after nephrectomy, but longterm longitudinal studies are lacking. The renal function and blood pressure of 75 donors was evaluated in 1984, 1.4-20.7 years after surgery. Forty-seven of the original cohort (23 male, age 38-80 years) underwent repeat study a decade later (12-31 years post-nephrectomy), using identical laboratory techniques. Glomerular filtration rates (GFR) as measured by 51Cr EDTA clearance was relatively unchanged a decade later with 41 of 47 subjects (87%) having EDTA clearance within the normal laboratory reference range at review. The change in GFR in the remaining six subjects was statistically not significant. No correlation between GFR and time after nephrectomy was detected. Albumin excretion rate (AER), on timed overnight urine collections, was increased (> 20 micrograms/min) in 16 subjects (34%), although 14 of these individuals were also hypertensive. The prevalence of hypertension was significantly increased compared with age/sex matched data from epidemiological studies of the general population (both in the UK and the US), especially in those over the age of 55 years. This study demonstrates that the function of the solitary kidney is not adversely affected by prolonged compensatory hyperfiltration, although there appears to be an increased prevalence of microalbuminuria and hypertension. Regular follow-up of kidney donors is recommended in order to manage their complications effectively and to detect hypertension and or renal impairment early in those who may develop it.