Racial disparities in renal transplantation in children

Racial disparities in paediatric kidney transplantation

BACKGROUND

Transplantation is the preferred treatment for children with end-stage kidney disease (ESKD). Pre-emptive transplants, those from live donors and with few human leukocyte antigen (HLA) mismatches provide the best outcomes. Studies into disparities in paediatric transplantation to date have not adequately disentangled different transplant types.

METHODS

We studied a retrospective cohort of 823 patients aged <18 years who started renal replacement therapy (RRT) in Australia 1990-2011, using the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA). The primary outcomes were time to first kidney transplant and kidney donor type (deceased or living), analysed using competing risk regression.

RESULTS

Caucasian patients were most likely to receive any transplant, due largely to disparities in live donor transplantation. No Indigenous patients received a pre-emptive transplant. Indigenous patients were least likely to receive a transplant from a live donor (sub-hazard ratio 0.41, 95 % confidence interval 0.20-0.82, compared to Caucasians). Caucasian recipients had fewer HLA mismatches, were less sensitised and were more likely to have kidney diseases that could be diagnosed early or progress slowly.

CONCLUSIONS

Caucasian paediatric patients are more likely to receive optimum treatment--a transplant from a living donor and fewer HLA mismatches. Further work is required to identify and address barriers to live donor transplantation among minority racial groups.

Racial disparities in access to pediatric kidney transplantation since share 35

Share 35 was enacted in 2005 to shorten transplant wait times and provide high-quality donors to children with ESRD. To investigate the possible effect of this policy on racial disparities in access to pediatric transplantation, we analyzed data from the US Renal Data System before and after Share 35. Among 4766 pediatric patients with incident ESRD, the probability of receiving a deceased-donor kidney transplant increased 46% after Share 35, with Hispanics experiencing the greatest improvements (increases of 81% for Hispanics, 45% for blacks, and 37% for whites). On average, patients received a deceased-donor kidney transplant earlier after Share 35, but this finding varied by race: 63 days earlier for whites, 90 days earlier for blacks, and 201 days earlier for Hispanics. Furthermore, a shift from living- to deceased-donor sources occurred with Share 35 for all races, with a 25% reduction in living donors for whites compared with 48% and 46% reductions for Hispanics and blacks, respectively. In summary, Share 35 seems to have attenuated racial disparities in the time to and probability of children receiving a deceased-donor kidney transplant. These changes coincided with changes in the rates of living-donor sources, which vary by race. Future studies should explore how these changes may impact racial differences in long-term graft outcomes.

Does immigration background influence outcomes after renal transplantation?

Migration implies differences in lifestyle, dietary and health behavior practice, and adherence, all of which are relevant factors in terms of disease outcome. However, renal transplantation in immigrant groups has been rarely studied in Europe. We have investigated the effect of immigration on outcomes in all children who underwent renal transplantation (RTx) at the Medical University of Vienna. From 1978 to 2007, 196 children underwent 236 RTx. In comparison to native recipients, immigrant recipients (31 boys, 17 girls) tended to be younger and male, with a higher rate of congenital renal diseases. The percentage of adolescent immigrant recipients tended to be lower, and living donation tended to be higher. In both the immigrant and native groups, RTx outcomes at 1, 5, and 10 years, including acute rejection rate (34 vs. 44, 55 vs. 62, 74 vs. 78%, respectively) and patient (98 vs. 92, 88 vs. 91, 80 vs. 82%, respectively) and graft survival (83 vs. 82, 79 vs. 65, 66 vs. 51%, respectively) were similar. All outcomes improved over time. In conclusion, this study demonstrates that outcomes in RTx are equivalent in immigrants and native recipients. Potential barriers to success among the Austrian immigrant recipient population may have been overcome by protective factors. These results should serve as a catalyst to retrieve data from larger databases to verify these single-center results.

Race and socioeconomic status influence outcomes of unrelated donor hematopoietic cell transplantation

Success of hematopoietic cell transplantation (HCT) can vary by race, but the impact of socioeconomic status (SES) is not known. To evaluate the role of race and SES, we studied 6207 unrelated-donor myeloablative (MA) HCT recipients transplanted between 1995 and 2004 for acute or chronic leukemia or myelodysplastic syndrome (MDS). Patients were reported by transplant center to be White (n = 5253), African American (n = 368), Asian/Pacific-Islander (n = 141), or Hispanic (n = 445). Patient income was estimated from residential zip code at time of HCT. Cox regression analysis adjusting for other significant factors showed that African American (but not Asian or Hispanic) recipients had worse overall survival (OS) (relative-risk [RR] 1.47; 95% confidence interval [CI] 1.29-1.68, P < .001) compared to Whites. Treatment-related mortality (TRM) was higher in African Americans (RR 1.56; 95% CI 1.34-1.83, P < .001) and in Hispanics (RR 1.30; 95% CI 1.11-1.51, P = .001). Across all racial groups, patients with median incomes in the lowest quartile (<$34,700) had worse OS (RR 1.15; 95% CI 1.04-1.26, P = .005) and higher risks of TRM (RR 1.21; 1.07-1.36, P = .002). Inferior outcomes among African Americans are not fully explained by transplant-related factors or SES. Potential other mechanisms such as genetic polymorphisms that have an impact on drug metabolism or unmeasured comorbidities, socioeconomic factors, and health behaviors may be important. Low SES, regardless of race, has a negative impact on unrelated donor HCT outcomes.

Outcome after renal transplantation in children from native and immigrant families in Austria

Renal transplantation is the therapy of choice for children with end-stage renal disease (ESRD). Ethnicity affects the transplant survival rates substantially, but there has been no European academic evaluation of the effects of immigration on the pediatric renal transplantation outcome. The aim of this study was to compare the outcomes of renal transplantation between the children of immigrant families and the children of native families at the pediatric nephrology unit of the Medical University of Vienna, Austria. We conducted a retrospective study on all children who underwent renal transplantation at our center between January 1997 and June 2005. The patients were separated into two groups according to their immigration backgrounds. During the time frame of our study, 59 children underwent a total of 63 transplantations. Of these children, 42 were from native Austrian and 17 were from first-generation immigrant families. We analyzed the demographic data and outcome parameters for each of the 59 patients. We found no difference in patient and graft survival rates or long-term function between native and immigrant children. The two groups were also comparable in the rates of acute rejection episodes, 24-h blood pressure, and growth velocity. Living donor source had a positive influence on graft function (p=0.06), 24-h blood pressure (p=0.05), and growth velocity (p=0.02) only in the immigrant group. Our retrospective analysis shows no influence of the migration status on the patient or graft outcome, but we did find that immigrant children benefitted more than native children from living donation as opposed to deceased donation. To explain this fact, biological, heath-economical, psychosocial, and cultural background aspects must be investigated.