Progression of urinary protein excretion after kidney transplantation: A marker for poor long-term prognosis.

INTRODUCTION Post-transplantation proteinuria is a risk factor for graft failure. A progressive decline in renal graft function is a predictor for mortality in kidney transplant patients. OBJECTIVES To assess the development and the progression of urinary protein excretion (UPE) in the first year post-transplant in recipients of kidney transplants and its effect on patient and graft outcomes. MATERIALS AND METHODS We analysed 1815 patients with 24-h UPE measurements available at 3 and 12 months post-transplant. Patients were divided based on their UPE level: below 300 mg, 300-1000 mg and over 1000 mg (at 3 and 12 months), and changes over time were analysed. RESULTS At 3 months, 65.7% had UPE below 300 mg/24 h, 29.6% 300-1000 mg/24 h and 4.7% over 1000 mg/24h. At one year, 71.6% had UPE below 300 mg/24 h, 24.1% 300-1000 mg/24 h and 4.4% over 1000 mg/24 h. In 208 patients (12%), the UPE progressed, in 1233 (70.5%) it remained stable and in 306 (17.5%) an improvement was observed. We found that the level of UPE influenced graft survival, particularly if a progression occurred. Recipient's age and renal function at one year were found to be predictive factors for mortality, while proteinuria and renal function were predictive factors for graft survival. CONCLUSIONS Proteinuria after transplantation, essentially when it progresses, is a marker of a poor prognosis and a predictor for graft survival. Progression of proteinuria is associated with poorer renal function and lower graft survival rates.