Relevance of deceased donor proteinuria for kidney transplantation: A comprehensive national cohort study

Abstract

Purpose: Proteinuria is frequent in patients with nephropathies and associated with progressive kidney disease and risk for end stage kidney disease. However, the relevance of deceased donor proteinuria on transplant outcome remains uncertain. In this nationwide cohort study, we evaluated the prevalence of proteinuria in deceased donor candidates and measured the impact on outcome after kidney transplantation. Methods: Data from the Swiss Organ Allocation System and the Swiss TransplantCohort Study were analyzed, comprising 1725 donors and 1516 recipients transplanted between 2008 and 2019. We correlated urine findings with donor characteristics and quantified the impact of proteinuria on allograft function at 12 months and survival.Results: Proteinuria influenced allocation decisions in 4.5% of nonimmunological organ declines and was the leading cause for decline in 0.2% of cases. 74.1%, 51.4%, and 35.3% of donor candidates had a baseline proteinuria above 15, 30, and 50 mg protein/mmol urine creatinine, respectively. Proteinuria above 30 mg/mmol was associated with female donor sex, mechanical resuscitation, acute kidney injury, and time delay between ICU entry and urine sampling. Donor proteinuria was not associated with patient or allograft survival, nor allograft function at 12 months. Conclusion:We report a high prevalence of proteinuria in donor candidates, without evidence of a deleterious impact of proteinuria on graft function and/or survival.Therefore, low-level proteinuria should not be considered a limiting contraindication for kidney allocation in deceased donor transplant.

Donor Proteinuria and Allograft Function in Kidney Transplantation: Short- and Long-Term Results From a Retrospective Cohort Study

“…This study established that within a 36 months post-transplant follow-up period, DP was not associated with impaired patient or graft survival or impaired graft function. Our results affirm the previous findings of Kuhn et al [ 8 ], who demonstrated that there was no effect of DP in KTX on graft survival or function within 12 months after surgery [ 8 ].…”

“…The prevalence of proteinuria in kidney transplant recipients ranges from 7.5% to 45% [ 7 ]. However, proteinuria is much more prevalent in organ donors, with low- and high-grade proteinuria occurring in 35.1% and 74.1% of allocated kidneys, respectively [ 8 ]. Yet, there are no official guidelines regarding donor proteinuria (DP) in kidney allocation, and the long-term impact of DP as an independent risk factor has not yet been validated.…”

Utilization and clinical outcomes of kidney transplants from deceased donors with albuminuria in the UK: a national cohort study

“…28 Recently, a national cohort study in Switzerland, which had a smaller sample size but longer follow-up than ours, found no association between deceased donor proteinuria, defined as uPCR >30mg/mmol, and graft survival or function. 26 Our findings add to the literature by showing consistent results in an adequately powered study that includes more DCD transplants, using a biomarker that is more widely reported at the time of donor assessment. In the subgroup of donors with uPCR recorded, we found consistent results despite applying a higher threshold (≥100 mg/mmol), although low numbers and potential selection bias limit interpretation of this result.…”

“…25,27 Our utilisation analysis supports recent work, suggesting that urinary findings are taken into account when considering kidney offers. 26 The strengths of this study are its size, national coverage, data completeness and minimal loss to follow-up. We were able to account for several potential confounders of the relationships in question, and our results were consistent across several outcomes and when using other categorisations of albuminuria.…”

“…Although grafts from donors with proteinuria may have more acute and chronic injury at the time of implantation, a relationship with clinical outcomes is unproven. [24][25][26][27][28] Evidence on deceased donors mainly comes from studies in which donors with brain death (DBD) predominate; this may not be generalisable to transplant programs with more donation after cardiac death (DCD), such as in the UK. Furthermore, urine protein : creatinine ratio (uPCR) is often unavailable at the time of donor assessment; consequently, substantial missing data reduces the power of previous studies and may introduce selection bias.…”