Long-Term Renal Function of Older Live Kidney Donors at Japanese Single Center

Abstract

Introduction: In Japan, live kidney transplantation occupied about 85% of all kidney transplantation. Because of the lack of deceased donors and increasing recipient age, the number of older donors is increasing. The Japanese society for clinical renal transplantation recommends to evaluate the adaptation carefully of donors seventy years and older. Material and methods: From 1990 to 2010, a total of 86 nephrectomies in living donors were performed at Japanese Kumamoto Red Cross Hospital. We are able to obtain information on 73 patients of the 86 donors (85%). We assessed the long-term renal outcome and graft survival after kidney donation from older live kidney donors(≥60 years old) compared to younger donors(< 60years). Results: Forty-seven donors were younger than 60 years and twenty-six were 60-years or older. Median follow-up was 5.3 years. Elderly had more hypertention before donation. Body mass index, smoking status and the time since donation were similar among the two groups. Elderly had a lower estimated glomerular filtration rate(eGFR) predonation (86.8±15.7 vs 76.0±8.9 ml/min/1.73m2, p< 0.05), but eGFR at latest was not different. In both groups, eGFR declined about 40% just after nephrectomy, but residual renal function was stable on long term follow-up. 10 donors (13.7%) were observed whose eGFR declined 10% more than that at discharge (7 in younger, 3 in older). The risk factor of impaired renal function after nephrectomy is hypertension which included new onset. Age, sex, smoking status, BMI are not associated with deterionate of renal function. One older donor died of arrhythmia during the follow-up period. There were two donors whose eGFR declined under 30 ml/min/1.73 m2. One older donor needed dialysis after 11 years of donation. One younger donor's eGFR declined 22ml/min/1.73 m2. Their renel function declined after complications such as heart failure, malignancy. In older donors, there were no complications which required extended hospital stay. Graft survival is similar in both groups. Conclusion: In our survey, donor age didn't influence deterioration of renal function after nephrectomy. Hypertention is related with decline of eGFR progressively. If we screen carefully, donation of older people is considered to be safe. Regardless of age, careful evaluation and follow-up are important for donor's safety after donation.