LAUSR

OBJECTIVES In this study, we evaluated the occurrence of proteinuria in living kidney donors during the immediate postdonation period, aiming to determine its clinical significance in renal function recovery. PATIENTS AND METHODS We enrolled living kidney donors with predonation protein excretion rate (PER) < 150 mg/24 h. Participants were divided into 2 groups according to immediate postdonation PER (4 days after nephrectomy): non-microproteinuria (non-mPr; PER < 150 mg/24 h), n = 244; and immediate postdonation microproteinuria (ImPr; PER ≥ 150 mg/24 h), n = 605. RESULTS Estimated glomerular filtration rate (eGFR) did not differ significantly between groups immediately after nephrectomy but was consistently lower in the ImPr group 1 week to 1 year postdonation (1-year postdonation eGFR: ImPr group, 63.6 ± 12.1 mL/min/1.73 m2; non-mPr group, 68.6 ± 12.3 mL/min/1.73 m2; P = .001). Immediate postdonation microproteinuria was an independent predictor of eGFR at 1 year postdonation (β [standard error] = -2.68 [1.15], 95% confidence interval -4.94 to -0.42, P = .02), along with predonation eGFR, age, and sex. Immediate postdonation microproteinuria was more common in donors who were older or male and occurred in 71.3% of kidney donors, suggesting renal injury in this period. CONCLUSIONS Although proteinuria generally resolves, its impact persists and can impair renal function recovery. Donors who are older and male are more likely to undergo immediate hyperfiltration after donation.