Genetic versus self-reported African ancestry of the recipient and neighborhood predictors of kidney transplantation outcomes in 2 multiethnic urban cohorts

African American (AA) kidney recipients have a higher risk of allograft rejection and failure compared to non-AAs, but to what extent these outcomes are due to genetic versus environmental effects is currently unknown. Herein, we tested the effects of recipient self-reported race versus genetic proportion of African ancestry (pAFR), and neighborhood socioeconomic status (SES) on kidney allograft outcomes in multiethnic kidney transplant recipients from Columbia University (N = 1083) and the University of Pennsylvania (N = 738). All participants were genotyped with SNP arrays to estimate genetic admixture proportions. US census tract variables were used to analyze the effect of neighborhood factors. In both cohorts, self-reported recipient AA race and pAFR were individually associated with increased risk of rejection and failure after adjustment for known clinical risk factors and neighborhood SES factors. Joint analysis confirmed that self-reported recipient AA race and pAFR were both associated with a higher risk of allograft rejection (AA: HR 1.61 (1.31-1.96), P = 4.05E-06; pAFR: HR 1.90 (1.46-2.48), P = 2.40E-06) and allograft failure (AA: HR 1.52 (1.18-1.97), P = .001; pAFR: HR 1.70 (1.22-2.35), P = .002). Further research is needed to disentangle the role of genetics versus environmental, social, and structural factors contributing to poor transplantation outcomes in kidney recipients of African ancestry.

Individual- and Community-Level Socioeconomic Status and Deceased Donor Renal Transplant Outcomes

BACKGROUND

This study examined the relationship between socioeconomic status (SES), race, and ethnicity and clinical outcomes following deceased donor kidney transplant (DDKT) at a high-volume transplant center.

METHODS

This retrospective cohort study used regression models and survival analyses to examine the relationship between individual- and community-level SES, race, and ethnicity and DDKT outcomes (i.e., delayed graft function, graft failure, mortality) adjusting for potential confounders.

RESULTS

The analytic sample included 3366 patients; 40.7% (n = 1370) were female, the mean age was 54.7 (SD = 13.3) years, 49.3% were non-Hispanic White, and the median follow-up time was 39.5 months (IQR = 24.2-68.1). Patients living in the most disadvantaged communities (using the US Census data) had a higher likelihood of delayed graft function (adjusted relative risk [RR] = 1.12, p = 0.042) and a higher hazard of mortality (adjusted hazard ratio [HR] = 1.32, p = 0.025) compared to patients living in the least disadvantaged communities. Patients without a high school diploma had a higher risk of delayed graft function compared to patients with an associate degree or more (RR = 1.37, p < 0.001). Patients with public insurance coverage had a higher risk of delayed graft function (RR = 1.24, p < 0.001) and a higher hazard of mortality (HR = 1.37, p < 0.001) and graft failure (HR = 1.71, p < 0.001) compared to patients without public insurance. There were no differences in graft failure or mortality by race and ethnicity.

CONCLUSIONS

SES was not consistently associated with outcomes following DDKT; however, many of the predictors were associated with delayed graft function. With a large and diverse sample size, these findings further the heterogeneity of the present renal transplant research suggesting the need for further investigation to guide implementation of innovative strategies and interventions.

MyKidneyCoach, Patient Activation, and Clinical Outcomes in Diverse Kidney Transplant Recipients: A Randomized Control Pilot Trial

Kidney transplant (KT) recipients who are not actively engaged in their care and lack self-management skills have poor transplant outcomes, which are disproportionately observed among Black KT recipients. This pilot study aimed to determine whether the MyKidneyCoach app, an mHealth intervention that provides self-management monitoring and coaching, improved patient activation, engagement, and nutritional behaviors in a diverse KT population.

Methods

This was a randomized, age-stratified, parallel-group, attention-control, pilot study in post-KT patients. Participants were randomized into the attention-control with access to MyKidneyCoach for education and self-management (n = 9) or the intervention with additional tailored nurse coaching (n = 7). Feasibility, acceptability, and clinical outcomes were assessed.

Results

The acceptability of MyKidneyCoach by System Usability Scale was 67.5 (95% confidence interval [CI], 59.1-75.9). Completion rates based on actively using MyKidneyCoach were 81% (95% CI, 57%-93%) and study retention rate of 73%. Patient activation measure significantly increased overall by a mean of 11 points (95% CI, 3.2-18.8). Additionally, Black patients (n = 7) had higher nutrition self-efficacy scores of 80.5 (95% CI, 74.4-86.7) compared with 75.6 (95% CI, 71.1-80.1) in non-Black patients (n = 9) but lower patient activation measure scores of 69.3 (95% CI, 56.3-82.3) compared with 71.8 (95% CI, 62.5-81) in non-Black patients after 3 mo.

Conclusions

MyKidneyCoach was easy to use and readily accepted with low attrition, and improvements were demonstrated in patient-reported outcomes. Both Black and non-Black participants using MyKidneyCoach showed improvement in self-management competencies; thus, this intervention may help reduce healthcare inequities in KT.

Improving Access to HLA-Matched Kidney Transplants for African American Patients

Introduction

Kidney transplants fail more often in Black than in non-Black (White, non-Black Hispanic, and Asian) recipients. We used the estimated physicochemical immunogenicity for polymorphic amino acids of donor/recipient HLAs to select weakly immunogenic kidney transplants for Black vs. White or non-Black patients.

Methods

OPTN data for 65,040 donor/recipient pairs over a 20-year period were used to calculate the individual physicochemical immunogenicity by hydrophobic, electrostatic and amino acid mismatch scores (HMS, EMS, AMS) and graft-survival outcomes for Black vs. White or vs. non-Black recipients, using Kaplan-Meier survival and Cox regression analyses. Simulations for re-matching recipients with donors were based on race-adjusted HMS thresholds with clinically achievable allocations.

Results

The retrospective median kidney graft survival was 12.0 years in Black vs. 18.6 years in White (6.6-year difference; p>0.001) and 18.4 years in non-Black (6.4-year difference; p>0.01) recipients. Only 0.7% of Blacks received transplants matched at HLA-A/B/DR/DQ (HMS=0) vs. 8.1% in Whites (p<0.001). Among fully matched Blacks (HMS=0), graft survival was 16.1-years and in well-matched Blacks (HMS ≤ 3.0) it was 14.0-years. Whites had 21.6-years survival at HMS ≤ 3.0 and 18.7-years at HMS ≤ 7.0 whereas non-Blacks had 22.0-year at HMS ≤ 3.0 and 18.7-year at HMS ≤ 7.0, confirming that higher HMS thresholds produced excellent survival. Simulation of ABO-compatible donor-recipient pairs using race-adjusted HMS thresholds identified weakly immunogenic matches at HMS=0 for 6.1% Blacks and 18.0% at HMS ≤ 3.0. Despite prioritizing Black patients, non-Black patients could be matched at the same level as in current allocation (47.0% vs 56.5%, at HMS ≤ 7.0).

Conclusions

Race-adjusted HMS (EMS, AMS)-based allocation increased the number of weakly immunogenic donors for Black patients, while still providing excellent options for non-Black recipients.

Socioeconomic inequality: Accessibility and outcomes after renal transplantation in New Zealand

BACKGROUND

Socioeconomic deprivation (SED) is a risk factor for worse outcomes after renal transplantation (RTx). This study aimed to evaluate access to RTx in different SED strata of the New Zealand population. We also assessed patient survival, acute cellular allograft rejection (AR) and allograft loss.

METHODS

This was an Australian and New Zealand Dialysis and Transplantation and Organ Donation Registries-based retrospective cohort study. Patients who underwent RTx in New Zealand from 2008 to 2018 were identified. Patients younger than 16 years of age and those who left the country after RTx were excluded.

RESULTS

In the higher SED stratum of New Zealanders, the rate of RTx was 53% greater than in the lower SED stratum (odds ratio = 1.53; 95% confidence interval: 1.33-1.76; p < 0.00005).

RESULTS

One hundred and thirteen (23%) patients from the lower SED group and 51 (14.8%) patients from the higher SED group underwent living unrelated RTx, p = 0.0033. In 233 (67.5%) patients from the higher SED group and 265 (53.9%) patients from the lower SED group, transplanted kidneys were from deceased donors RTx, p = 0.0001. The incidence of allograft loss and patient survival were similar in these groups.

CONCLUSION

Our data demonstrated a lower overall survival in the more socioeconomically deprived patients than in the lower SED group however this was not statistically significant after adjustment for covariates. A larger study is required to determine whether SED is associated with reduced survival.

African American polycystic kidney patients receive higher risk kidneys, but do not face increased risk for graft failure or post-transplant mortality

African Americans (AA) are disproportionately affected by end-stage renal disease (ESRD) and have worse outcomes following renal transplantation. Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic condition leading to ESRD necessitating transplant. We explored this population with respect to race by conducting a retrospective analysis of the UNOS database between 2005 and 2019. Our study included 10,842 (AA n = 1661; non-AA n = 9181) transplant recipients whose primary diagnosis was ADPKD. We further stratified the AA ADPKD population with respect to blood groups (AA blood type B n = 295 vs AA non-B blood type n = 1366), and also compared this cohort to AAs with a diagnosis of DM (n = 16,706) to identify unique trends in the ADPKD population. We analyzed recipient and donor characteristics, generated survival curves, and conducted multivariate analyses. African American ADPKD patients waited longer for transplants (924 days vs 747 days P < .001), and were more likely to be on dialysis (76% vs 62%; p < .001). This same group was also more likely to have AA donors (21% vs 9%; p < .001) and marginally higher KDPI kidneys (0.48 vs 0.45; p < .001). AA race was a risk factor for delayed graft function (DGF), increasing the chance of DGF by 45% (OR 1.45 95% CI 1.26-1.67; p < .001). AA race was not associated with graft failure (HR 1.10 95% CI 0.95-1.28; p = .21) or patient mortality (HR 0.84 95% CI 0.69-1.03; p = .09). Racial disparities exist in the ADPKD population. They should be continually studied and addressed to improve transplant equity.