Consequences of Nephrotic Proteinuria and Nephrotic Syndrome after Kidney Transplant

TL;DR

Nephrotic proteinuria and syndrome after kidney transplants are common and strongly linked to poor outcomes, with early development of syndrome indicating worse survival.

Contribution

The study provides new insights into the clinical and histopathological features of nephrotic-range proteinuria and its association with graft survival after kidney transplantation.

Findings

Nephrotic-range proteinuria occurred in 18.6% of kidney transplants.

Graft survival dropped from 75.8% at 12 months to 38% at 5 years after NP onset.

Early development of nephrotic syndrome was linked to higher graft loss risk.

Abstract

Proteinuria is the main predictor of kidney graft loss. However, there is little information regarding the consequences of nephrotic proteinuria (NP) and nephrotic syndrome (NS) after a kidney transplant. We aimed to describe the clinical and histopathological characteristics of kidney recipients with nephrotic-range proteinuria and compare the graft surveillance between those who developed NS and those who did not. A total of 204 patients (18.6% of kidney transplants in the study period) developed NP, and 68.1% of them had NS. Of the 110 patients who underwent a graft biopsy, 47.3% exhibited ABMR, 21.8% the recurrence of glomerulonephritis, 9.1% IFTA, and 7.3% de novo glomerulonephritis. After a median follow-up of 97.5 months, 64.1% experienced graft loss. The graft survival after the onset of NP declined from 75.8% at 12 months to 38% at 5 years, without significant differences between those with and those without NS. Patients who developed NS fewer than 3 months after the onset of NP exhibited a significantly higher risk of death-censored graft loss (HR: 1.711, 95% CI: 1.147–2.553) than those without NS or those with late NS. In conclusion, NP and NS are frequent conditions after a kidney transplant, and they imply extremely poor graft outcomes. The time from the onset of NP to the development of NS is related to graft survival.

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