Introduction: The safety of donors is one of the most important issues in living donor kidney transplantation. We aimed to investigate predictors of renal outcome in living kidney donors that can help guide management of living kidney donors.
Methods: We analyzed data of kidney donors who were registered to a nationwide prospective registry, the Korean Organ Transplantation RegistrY (KOTRY), from May 2014 to December 2016. Among a total of 1,497 living kidney donors, 456 donors were followed up until 2 years with available serum creatinine measurement after kidney transplantation. We analyzed factors related to renal outcome of donors. Chronic kidney disease (CKD) was defined as estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m2 or spot urine protein-to-creatinine ratio ≥ 150mg/g or spot urine microalbumin-to-creatinine ratio ≥ 30mg/g or 24-hour urine protein ≥ 150mg.
Results: At 2 years after kidney transplantation, CKD developed in 99 (21.7%) donors. Donors who had incident CKD were older (50.1 ± 10.8 vs. 42.5 ± 11.7 years-old), had more hypertension (12.1% vs. 5.0%), had higher serum uric acid (5.4 ± 1.5 mg/dL vs. 4.9 ± 1.4 mg/dL) and glucose level (102 ± 18 mg/dL vs. 97 ± 12 mg/dL), and lower predonation eGFR (88 ± 13 mL/min/1.73m2 vs. 106 ± 13 mL/min/1.73m2) than subjects who did not develop CKD. The eGFR decreased 0.4 ± 3.6 ml/min/1.73m2 per year since nephrectomy in incident CKD group, while it increased 2.2 ± 1.7 ml/min/1.73m2 per year in non-CKD group (p = 0.008). In multivariate logistic regression analysis, higher systolic blood pressure was associated with higher risk of CKD (Odds Ratio (OR), 1.322 per 10 mmHg increment; 95% Confidence Interval (CI), 1.036-1.686; p = 0.025), and higher predonation eGFR (OR, 0.906 per 1 ml/min/1.73m2 increment; 95% CI, 0.876-0.936; p < 0.001) and higher ratio of eGFR at discharge to predonation eGFR (OR, 0.603,1 per 0.1 increment; 95% CI, 0.428-0.849; p = 0.004) were related to lower risk of CKD.
Conclusion: Higher blood pressure was related to higher risk of CKD in kidney donors. Higher predonation eGFR and less decline of eGFR after single nephrectomy were predictors for long-term preservation of renal function.