The uneven distribution of kidney transplants: getting at the root causes and improving care

Sex Differences in Kidney Transplantation: Austria and the United States, 1978–2018

Background

Systematic analyses about sex differences in wait-listing and kidney transplantation after dialysis initiation are scarce. We aimed at identifying sex-specific disparities along the path of kidney disease treatment, comparing two countries with distinctive health care systems, the US and Austria, over time.

Methods

We analyzed subjects who initiated dialysis from 1979–2018, in observational cohort studies from the US and Austria. We used Cox regression to model male-to-female cause-specific hazard ratios (csHRs, 95% confidence intervals) for transitions along the consecutive states dialysis initiation, wait-listing, kidney transplantation and death, adjusted for age and stratified by country and decade of dialysis initiation.

Results

Among 3,053,206 US and 36,608 Austrian patients starting dialysis, men had higher chances to enter the wait-list, which however decreased over time [male-to-female csHRs for wait-listing, 1978–1987: US 1.94 (1.71, 2.20), AUT 1.61 (1.20, 2.17); 2008–2018: US 1.35 (1.32, 1.38), AUT 1.11 (0.94, 1.32)]. Once wait-listed, the advantage of the men became smaller, but persisted in the US [male-to-female csHR for transplantation after wait-listing, 2008–2018: 1.08 (1.05, 1.11)]. The greatest disparity between men and women occurred in older age groups in both countries [male-to-female csHR for wait-listing after dialysis, adjusted to 75% age quantile, 2008–2018: US 1.83 (1.74, 1.92), AUT 1.48 (1.02, 2.13)]. Male-to-female csHRs for death were close to one, but higher after transplantation than after dialysis.

Conclusions

We found evidence for sex disparities in both countries. Historically, men in the US and Austria had 90%, respectively, 60% higher chances of being wait-listed for kidney transplantation, although these gaps decreased over time. Efforts should be continued to render kidney transplantation equally accessible for both sexes, especially for older women.

Disparities in living donation

PURPOSE OF REVIEW

Living organ donation provides improved access to transplantation, thereby shortening transplant wait times and allowing for more deceased organ transplants. However, disparity in access to living donation has resulted in decreased rates of living donor transplants for some populations of patients.

RECENT FINDINGS

Though there have been marked improvements in deceased donor equity, there are still challenges as it relates to gender, racial/ethnic, and socio-economic disparity. Improvements in living donation rates in Hispanic and Asian populations are tempered by challenges in African American rates of organ donation. Socio-economic disparity may drive gender disparities in organ donation resulting in disproportionate female living donors. Tailored approaches relating to language-specific interventions as well as directed educational efforts have helped mitigate disparity. Additionally, the use of apolipoprotein1 testing and modifications of glomerular filtration rate calculators may improve rates of African American donation. This review will evaluate recent data in living donor disparity as well as highlight successes in mitigating disparity.

SUMMARY

Though there are still challenges in living donor disparity, many efforts at tailoring education and access as well as modifying living donor evaluation and identifying systemic policy changes may result in improvements in living donation rates.

Racism and Kidney Health: Turning Equity Into a Reality

Kidney disease continues to manifest stark racial inequities in the United States, revealing the entrenchment of racism and bias within multiple facets of society, including in our institutions, practices, norms, and beliefs. In this perspective, we synthesize theory and evidence to describe why an understanding of race and racism is integral to kidney care, providing examples of how kidney health disparities manifest interpersonal and structural racism. We then describe racialized medicine and "colorblind" approaches as well as their pitfalls, offering in their place suggestions to embed antiracism and an "equity lens" into our practice. We propose examples of how we can enhance kidney health equity by enhancing our structural competency, using equity-focused race consciousness, and centering investigation and solutions around the needs of the most marginalized. To achieve equitable outcomes for all, our medical institutions must embed antiracism and equity into all aspects of advocacy, policy, patient/community engagement, educational efforts, and clinical care processes. Organizations engaged in kidney care should commit to promoting structural equity and eliminating potential sources of bias across referral practices, guidelines, research agendas, and clinical care. Kidney care providers should reaffirm our commitment to structurally competent patient care and educational endeavors in which empathy and continuous self-education about social drivers of health and inequity, racism, and bias are integral. We envision a future in which kidney health equity is a reality for all. Through bold collective and sustained investment, we can achieve this critical goal.

Understanding and overcoming barriers to living kidney donation among racial and ethnic minorities in the United States

In the United States, racial-ethnic minorities experience disproportionately high rates of ESRD, but they are substantially less likely to receive living donor kidney transplants (LDKT) compared with their majority counterparts. Minorities may encounter barriers to LDKT at several steps along the path to receiving it, including consideration, pursuit, completion of LDKT, and the post-LDKT experience. These barriers operate at different levels related to potential recipients and donors, health care providers, health system structures, and communities. In this review, we present a conceptual framework describing various barriers that minorities face along the path to receiving LDKT. We also highlight promising recent and current initiatives to address these barriers, as well as gaps in initiatives, which may guide future interventions to reduce racial-ethnic disparities in LDKT.

Impact of human leukocyte antigen-DR mismatch status on kidney graft survival in a predominantly African-American population under the newer immunosuppressive era

BACKGROUND

Human leukocyte antigen (HLA)-DR has been shown to be immunogenic and associated with poor long-term graft function. However, under potent induction immunosuppression with antithymocyte globulin, the impact of the HLA-DR remains unclear.

METHOD

We reviewed 672 renal transplant recipients who received their transplants between 1998 and 2007. All patients received antithymocyte globulin as induction therapy followed by tacrolimus + prednisone + mycophenolate mofetil for maintenance immunosuppression. We divided the patients into three groups according to HLA-DR mismatch status (zero, one, or two mismatches).

RESULTS

The three groups were different in total number of mismatches, deceased donor transplant, and delayed graft function, respectively. By Kaplan-Meier survival analysis, actuarial graft survival was significantly lower in the HLA-DR two mismatches group (72%) compared to HLA-DR zero mismatches group (78.5%) or HLA-DR one mismatch group (78.5%; P = .05, by log-rank test). Using Cox regression analysis, the risk of graft failure with two HLA-DR mismatches as compared with zero HLA-DR mismatches was 1.6 (95% confidence interval = 1.0-2.44, P = .049). When adjusted for age, wait time, race, type of transplant, retransplant status, T-cell flow crossmatch, delayed graft function, acute rejection, HLA-A and HLA-B, the effect of HLA-DR on survival was not significant (P = .55).

CONCLUSION

The independent effect of HLA-DR mismatches on adverse graft survival is diminished under potent antibody induction and maintenance immunosuppression in our predominantly African-American population.

Barriers to living donor kidney transplantation among black or older transplant candidates

BACKGROUND AND OBJECTIVES

Lower rates of living donor kidney transplant (LDKT) among transplant candidates who are black or older may stem from lower likelihoods of (1) recruiting potential living donors or (2) potential donors actually donating (donor "conversion").

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A single-center, retrospective cohort study was performed to determine race, age, and gender differences in LDKT, donor recruitment, and donor conversion.

RESULTS

Of 1617 kidney transplant candidates, 791 (48.9%) recruited at least one potential living donor, and 452 (28.0%) received LDKTs. Black transplant candidates, versus non-blacks, were less likely to receive LDKTs (20.5% versus 30.6%, relative risk [RR] = 0.67), recruit potential living donors (43.9% versus 50.7%, RR = 0.86), and receive LDKTs if they had potential donors (46.8% versus 60.3%, RR = 0.78). Transplant candidates ≥60 years, versus candidates 18 to <40 years old, were less likely to receive LDKTs (15.1% versus 43.2%, RR = 0.35), recruit potential living donors (34.0% versus 64.6%, RR = 0.53), and receive LDKTs if they had potential donors (44.5% versus 66.8%, RR = 0.67). LDKT and donor recruitment did not differ by gender. Race and age differences persisted in multivariable logistic regression models. Among 339 candidates who recruited potential donors but did not receive LDKTs, blacks (versus non-blacks) were more likely to have potential donors who failed to donate because of a donor-related reason (86.9% versus 72.5%).

CONCLUSIONS

Black or older kidney transplant candidates were less likely to receive LDKTs because of lower likelihoods of donor recruitment and donor conversion.

Racial and geographic disparities in the utilization of surgical therapy for hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) continues to increase, a trend that will likely continue because of the rising prevalence of chronic hepatitis C infection. This study sought to determine the recent patterns of utilization of surgical therapy (hepatectomy, ablation, or liver transplantation) for HCC from the Surveillance, Epidemiology, and End Results national cancer registry. Data were extracted for 16,121 patients with HCC diagnosed between 1998 and 2004. Twenty-three percent of patients underwent surgical therapy (9.5% resection, 7.8% ablation, 6% transplant); the proportion of patients treated with surgical therapy increased approximately 9% over the study period. On multivariate analysis, female sex, younger age, and smaller solitary tumors were associated with increased utilization of surgical therapy. Blacks and Hispanics were 24-27% less likely to receive surgical therapy than white individuals (P<0.001). Racial and geographic disparities persisted despite the adjustment for Health Service Area and limitation of the cohort to small localized HCC. Blacks were especially disadvantaged in the utilization of liver transplant for small HCC (OR=0.42, P<0.001). Further investigation to understand the etiology of these profound racial and geographic disparities is essential to ensure equitable provision of surgical therapies, which provide the only potentially curative treatments for HCC.

The Influence of Patient Race and Social Vulnerability on Urologist Treatment Recommendations in Localized Prostate Carcinoma

BACKGROUND

In localized prostate carcinoma (PCa), many studies have found that black subjects receive radical prostatectomy (RP) less often than white subjects. Such disparities involve barriers to health care, comorbid illnesses, tumor characteristics, and patient preferences. It is unclear whether differences in urologist treatment recommendations also might play a role.

METHODS

Using a randomized, 2 x 2 factorial design, we presented 2000 urologists with a clinical vignette and asked them to recommend treatment of a healthy 70-year-old patient with low-risk, clinically localized PCa. Options included either RP, external beam radiotherapy, brachytherapy, cryotherapy, observation, or hormonal therapy. There were 2 variables within 4 otherwise-identical versions of the vignette: 1) patient race (black vs. white) and 2) social vulnerability (middle-income and married vs. low-income and widowed). We used multivariable logistic regression to model the effects of patient race, social vulnerability, and their interaction on recommendations for RP versus radiotherapy.

RESULTS

The response rate was 66.1% (n = 1313). Race and social vulnerability interacted (P = 0.05) such that the highly vulnerable black patient received an RP recommendation 14.4% less often than his less vulnerable counterpart; the difference between the 2 white patients was 4.2%.

DISCUSSION

Race interacts with social vulnerability to influence urologist recommendations for RP. Because PCa tends to be more lethal in blacks, urologists may view such patients as good candidates for RP. However, black race may amplify perceptions of social vulnerability, heightening urologists' concerns about poor surgical outcomes and follow-up. These findings affirm the importance of modeling interactions between race/ethnicity and other social variables in health disparities research.

Rates of completion of the medical evaluation for renal transplantation

BACKGROUND

Failure to complete the medical evaluation for renal transplantation may impede access to transplantation and preclude the possibility of preemptive transplantation. We sought to (1) characterize completion rates of the transplantation medical evaluation and (2) determine factors associated with completion of the evaluation. We hypothesized that patients not on dialysis therapy complete the evaluation process more quickly than patients receiving dialysis.

METHODS

Between September 2002 and September 2003, a total of 175 patients who were evaluated for renal transplantation at the Hospital of the University of Pennsylvania were enrolled in a prospective cohort study. Patients completed a self-administered questionnaire. The progress of patients' medical evaluations, including completion of requested tests and evaluations, was extracted from the electronic medical record.

RESULTS

During follow-up, 100 patients (57.1%) completed the evaluation, including tests and evaluations requested by the transplant team, whereas 49 patients (28.0%) had tests still pending. The remaining patients died (2.3%), lost interest in transplantation (1.1%), or were immediately (7.4%) or later (4.0%) declared medically ineligible for transplantation. In the multivariable Cox proportional hazards model, black race (adjusted hazard ratio, 0.63; 95% confidence interval, 0.40 to 1.00; P = 0.05) was associated with time to completion of the transplantation evaluation, but receiving maintenance dialysis at the time of the initial transplantation evaluation was not (adjusted hazard ratio, 0.92; 95% confidence interval, 0.60 to 1.42; P = 0.72).

CONCLUSION

Completion of the medical evaluation for transplantation is slower in blacks than nonblacks. We were unable to detect a significant difference between dialysis and nondialysis patients in rates of completion of the evaluation.

Kidney transplantation and gender disparity

Gender inequity in access to hemodialysis and kidney transplantation has created a public health crisis in the US. Women have a lower chance of receiving hemodialysis and kidney transplant than men, but they constitute the majority of living kidney donors. Research has shown that economic factors such as greater income of men may encourage females to be donors; while gender-bias on part of physicians or institutions, lack of social support networks and differences in health-seeking behaviors compared to men are cited as reasons for this imbalance. We suggest various strategies to improve participation of women in the transplant process by education; raising awareness by publishing gender-specific data for dialysis and transplant centers; education and workshops to eliminate gender-bias within institutions and health-care providers and establishment of gender-specific support groups. Transplant teams that are more sensitive to the social complexities of women's lives may lead to increased understanding of the effects of renal disease and indicate measures that need to be in place in order to address this gender disparity in the treatment of renal failure. Research needs to be done to elucidate the underlying medical, societal or psychological processes that lead to gender bias in the field of kidney transplantation.

Allocation of deceased donor kidneys: past, present, and future

The manner in which deceased donor kidneys are allocated has broad relevance to the care of patients with end-stage renal disease. An algorithm governing the allocation of deceased donor kidneys has been applied in the United States since 1987. Adjustments were made to facilitate the national sharing of highly matched kidneys, but the main components of the algorithm remained largely unchanged. In ensuing years, the number of patients on the waiting list has increased steadily while the supply of kidneys has remained constant. The waiting time for an organ now is measured in years, and the allocation of organs has become unpredictable. As of October 2002, several important changes have been made to the algorithm. These changes are designed to increase the relative number of minority patients who undergo transplantation and the use of extended-criteria donor kidneys. They also have practical implications for the management of patients on the waiting list. The rationale behind these changes is discussed in the context of the ethical underpinnings of kidney allocation.