Renal outcome 25 years after donor nephrectomy

Purpose: The extended outcome after kidney donation has been a particular c oncern ever since the recognition of hyperfiltration injury. Few published reports have examined donor renal outcome after 20 years or greater. Kidney transplantation has been performed at the Cleveland Clinic Foundation sinc e 1963, at which there is extensive experience with live donor transplantat ion. We assess the impact of donor nephrectomy on renal function, urinary p rotein excretion and development of hypertension postoperatively to examine whether renal deterioration occurs with followup after 20 years or greater . Materials and Methods: From 1963 to 1975, 180 live donor nephrectomies were performed at the Cleveland Clinic. We attempted to contact all patients to request participation in our study. Those 70 patients who agreed to partic ipate in the study were mailed a package containing a 24-hour urine contain er (for assessment of creatinine, and total protein and albumin;), a vial f or blood collection (for assessment of serum creatinine) and a medical ques tionnaire. All specimens were returned to and processed by the Cleveland Cl inic medical laboratories. Blood pressure was taken and recorded by a local physician. A 24-hour creatinine clearance and the Cockcroft-Gault formula were used to estimate renal function, and values were compared with an age adjusted glomerular filtration rate for a solitary kidney. Results: Mean patient followup was 25;years. The 24-hour urinary creatinine clearance decreased to 72% of the value before donation. For the entire st udy cohort serum creatinine and systolic blood pressure after donation were significantly increased compared with values before, although still in the normal range. The overall incidence of hypertension was comparable to that expected in the age matched general population. There was no gender or age difference (younger or older than 50 years) for 24-hour urinary creatinine clearance, or change in serum creatinine before or after donation. Urinary protein and albumin excretion after donation was significantly higher in m ales compared with females. There were 13 (19%) subjects who had a 24-hour urinary protein excretion that was greater than 0.15 gm./24 hours, 5 (7%) o f whom had greater than 0.8. No gender difference was noted in blood pressu re, and there were no significant changes in diastolic pressure based on ge nder or age. Conclusions: Overall, renal function is well preserved with a mean followup of 25 years after donor nephrectomy. Males had significantly higher protei n and albumin excretion than females but no other clinically significant di fferences in renal function, blood pressure or proteinuria were noted betwe en them or at age of donation. Proteinuria increases with marginal signific ance but appears to be of no clinical consequence in most patients. Patient s with mild or borderline proteinuria before donation may represent a subgr oup at particular risk for the development of significant proteinuria 20 ye ars or greater after donation. The overall incidence of proteinuria in our study is in the range of previously reported values after donor nephrectomy .