Association of Primary Kidney Disease Type and Donor Relatedness With Live Donor Kidney Transplant Outcomes: An Analysis of ANZDATA

RATIONALE & OBJECTIVE

There is limited information about the association between primary kidney disease and donor relatedness with transplant outcomes. This study addresses this gap by evaluating clinical outcomes after kidney transplantation in recipients of living donor kidneys as a function of primary kidney disease type and donor relatedness in Australia and New Zealand.

STUDY DESIGN

Retrospective observational study.

SETTING & PARTICIPANTS

Kidney transplant recipients who received allografts from living donors between January 1, 1998, and December 31, 2018, as recorded in the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA).

EXPOSURES

Primary kidney disease type categorized as majority monogenic, minority monogenic, or other primary kidney disease based on disease heritability as well as donor relatedness.

OUTCOME

Primary kidney disease recurrence, graft failure.

ANALYTICAL APPROACH

Kaplan-Meier analysis and Cox proportion hazards regression to generate hazard ratios for primary kidney disease recurrence, allograft failure, and mortality. Partial likelihood ratio test was used to examine possible interactions between primary kidney disease type and donor relatedness for both study outcomes.

RESULTS

Among 5,500 live donor kidney transplant recipients, majority monogenic (adjusted HR, 0.58, P<0.001) and minority monogenic primary kidney diseases (adjusted HR, 0.64, P<0.001) were associated with reduced primary kidney disease recurrence compared with other primary kidney diseases. Majority monogenic primary kidney disease was also associated with reduced allograft failure (adjusted HR, 0.86, P=0.04) compared with other primary kidney diseases. Donor relatedness was not associated with primary kidney disease recurrence nor graft failure. No interaction was detected between primary kidney disease type and donor relatedness for either study outcome.

LIMITATIONS

Potential misclassification of primary kidney disease type, incomplete ascertainment of primary kidney disease recurrence, unmeasured confounding.

CONCLUSIONS

Monogenic primary kidney disease is associated with lower rates of primary kidney disease recurrence and allograft failure. Donor relatedness was not associated with allograft outcomes. These results may inform pretransplant counseling and live donor selection.

PLAIN-LANGUAGE SUMMARY

There are theoretical concerns that live-donor kidney transplants may be associated with increased risks of kidney disease recurrence and transplant failure due to unmeasurable shared genetic factors between the donor and the recipient. This study analyzed data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) registry and showed that, although disease type was associated with the risk of disease recurrence and transplant failure, donor relatedness did not impact transplant outcomes. These findings may inform pretransplant counseling and live donor selection.

Beyond Graft Survivl: A National Cohort Study Quantifying the Impact of Increasing Kidney Donor Profile Index on Recipient Outcomes 1 Year Post-transplantation

Background.

The reporting of a locally validated kidney donor profile index (KDPI) began in Australia in 2016. Across diverse populations, KDPI has demonstrated utility in predicting allograft survival and function. A metric that incorporates both elements may provide a more comprehensive picture of suboptimal recipient outcomes.

Methods.

A retrospective cohort study of adult kidney transplant recipients in Australia (January 2009 to December 2014) was conducted. Conventional recipient outcomes and a composite measure of suboptimal outcome (1-y allograft failure or estimated glomerular filtration rate [eGFR] <30 mL/min) were evaluated across KDPI intervals (KDPI quintiles and 5-point increments in the KDPI 81–100 cohort). The impact of increasing KDPI on allograft function (1-y eGFR) and a suboptimal outcome was explored using multivariable regression models, adjusting for potential confounding factors.

Results.

In 2923 donor kidneys eligible for analysis, median KDPI was 54 (interquartile range [IQR], 31–77), and Kidney Donor Risk Index was 1.39 (IQR, 1.03–1.67). The median 1-y eGFR was 52.74 mL/min (IQR, 40.79–66.41 mL/min). Compared with the first quintile reference group, progressive reductions in eGFR were observed with increasing KDPI and were maximal in the fifth quintile (adjusted β-coefficient: −27.43 mL/min; 95% confidence interval, –29.44 to –25.42; P < 0.001). A suboptimal outcome was observed in 359 recipients (12.3%). The adjusted odds for this outcome increased across quintiles from a baseline of odds ratio of 1.00 (first quintile) to odds ratio of 11.68 (95% confidence interval, 6.33-21.54, P < 0.001) in the fifth quintile cohort.

Conclusions.

Increases in donor KDPI were associated with higher probabilities of a suboptimal outcome and poorer baseline allograft function, particularly in the KDPI > 80 cohort. These findings may inform pretransplant discussions with potential recipients of high-KDPI allografts.

Organ transplantation and outcomes in patients with a past history of melanoma: A systematic review and meta-analysis

BACKGROUND

The incidence of melanoma is steadily rising around the world. There is uncertainty about the safety of solid organ transplantation in patients with a prior history of melanoma.

AIM

To review studies reporting patients with a history of melanoma before solid organ transplantation.

METHODS

Electronic searches of Medline, Embase, and the Cochrane library up to March 2020. All study designs, in any language and without sample size restriction, were eligible for inclusion. Risk of bias was assessed using established tools, and meta-analysis was performed using a random-effects model.

RESULTS

We identified 41 studies reporting 703 100 transplant recipients and 1692 had pre-transplantation melanomas. Risk of death, expressed as a hazard ratio, in patients with pre-transplantation melanoma relative to those without prior melanoma, was 1.32 (95% CI: 1.09-1.59). After transplantation, 13.1% of patients with pre-transplantation melanoma developed new or recurrent melanoma (IQR: 4.8%-18.2%).

CONCLUSIONS

Around 1-in-400 transplant recipients had a prior history of melanoma. This was associated with a greater than 1-in-10 risk of new or recurrent melanoma after transplantation and an increased risk of death. A 5-year waiting time between a melanoma diagnosis and transplantation has been recommended based on historic registry data, but very little additional information is available to justify or revise this.

Pharmacologic targeting of renal ischemia-reperfusion injury using a normothermic machine perfusion platform

Normothermic machine perfusion (NMP) is an emerging modality for kidney preservation prior to transplantation. NMP may allow directed pharmacomodulation of renal ischemia-reperfusion injury (IRI) without the need for systemic donor/recipient therapies. Three proven anti-IRI agents not in widespread clinical use, CD47-blocking antibody (αCD47Ab), soluble complement receptor 1 (sCR1), and recombinant thrombomodulin (rTM), were compared in a murine model of kidney IRI. The most effective agent was then utilized in a custom NMP circuit for the treatment of isolated porcine kidneys, ascertaining the impact of the drug on perfusion and IRI-related parameters. αCD47Ab conferred the greatest protection against IRI in mice after 24 hours. αCD47Ab was therefore chosen as the candidate agent for addition to the NMP circuit. CD47 receptor binding was demonstrated by immunofluorescence. Renal perfusion/flow improved with CD47 blockade, with a corresponding reduction in oxidative stress and histologic damage compared to untreated NMP kidneys. Tubular and glomerular functional parameters were not significantly impacted by αCD47Ab treatment during NMP. In a murine renal IRI model, αCD47Ab was confirmed as a superior anti-IRI agent compared to therapies targeting other pathways. NMP enabled effective, direct delivery of this drug to porcine kidneys, although further efficacy needs to be proven in the transplantation setting.

Complement: Bridging the innate and adaptive immune systems in sterile inflammation

The complement system is a collection of soluble and membrane-bound proteins that together act as a powerful amplifier of the innate and adaptive immune systems. Although its role in infection is well established, complement is becoming increasingly recognized as a key contributor to sterile inflammation, a chronic inflammatory process often associated with noncommunicable diseases. In this context, damaged tissues release danger signals and trigger complement, which acts on a range of leukocytes to augment and bridge the innate and adaptive immune systems. Given the detrimental effect of chronic inflammation, the complement system is therefore well placed as an anti-inflammatory drug target. In this review, we provide a general outline of the sterile activators, effectors, and targets of the complement system and a series of examples (i.e., hypertension, cancer, allograft transplant rejection, and neuroinflammation) that highlight complement's ability to bridge the 2 arms of the immune system.

Insights into the labeling effect of Kidney Donor Performance Index reporting: The Australian experience

In 2016, Australia began reporting the Kidney Donor Performance Index (KDPI) with all deceased donor kidney transplant offers despite this not being used in organ allocation rules, offering a unique opportunity to explore the "labeling effect" of KDPI reporting. We reviewed all kidneys retrieved for transplant in Australia from 2015 to 2018 and analyzed the association of KDPI reporting with organ nonutilization, number of offer declines, and donor/recipient age and longevity matching. Analyses were stratified by organ failure risk: higher risk (KDPI > 80%), standard risk (KDPI 20% to 79%), and lower risk (KDPI 0% to 20%). There was no significant difference in organ nonutilization post KDPI reporting either overall or for higher-risk kidneys. KDPI reporting was associated with an increase in offer declines for both higher-risk (incidence risk ratio 1.45, P = .007) and standard-risk (incidence risk ratio 1.22, P = .021) kidneys but not for lower-risk organs. There was a significant increase in recipient age and expected posttransplant survival score for higher-risk kidneys but no differences among other groups. We conclude that although KDPI reporting in Australia has been associated with an increased number of offer declines for higher-risk kidneys, this has not resulted in increased nonutilization and may have contributed to more appropriate use of these organs.