Renal transplantation in black Americans

Genotype-guided tacrolimus dosing in African-American kidney transplant recipients

Tacrolimus is dependent on CYP3A5 enzyme for metabolism. Expression of the CYP3A5 enzyme is controlled by several alleles including CYP3A5*1, CYP3A5*3, CYP3A5*6 and CYP3A5*7. African Americans (AAs) have on average higher tacrolimus dose requirements than Caucasians; however, some have requirements similar to Caucasians. Studies in AAs have primarily evaluated the CYP3A5*3 variant; however, there are other common nonfunctional variants in AAs (CYP3A5*6 and CYP3A5*7) that do not occur in Caucasians. These variants are associated with lower dose requirements and may explain why some AAs are metabolically similar to Caucasians. We created a tacrolimus clearance model in 354 AAs using a development and validation cohort. Time after transplant, steroid and antiviral use, age and CYP3A5*1, *3, *6 and *7 alleles were significant toward clearance. This study is the first to develop an AA-specific genotype-guided tacrolimus dosing model to personalize therapy.

Racial and Ethnic Disparities in Graft and Recipient Survival in Elderly Kidney Transplant Recipients

OBJECTIVES

To investigate racial and ethnic differences in graft and recipient survival in elderly kidney transplant recipients.

DESIGN

Retrospective cohort.

SETTING

First-time, kidney-only transplant recipients aged 60 and older of age at transplantation transplanted between July 1996 and October 2010 (N = 44,013).

PARTICIPANTS

United Network for Organ Sharing (UNOS) database.

MEASUREMENTS

Time to graft failure and death obtained from the UNOS database and linkage to the Social Security Death Index. Neighborhood poverty from 2000 U.S. Census geographic data.

RESULTS

Of the 44,013 recipients in the sample, 20% were black, 63% non-Hispanic white, 11% Hispanic, 5% Asian, and the rest "other racial groups." In adjusted Cox models, blacks were more likely than whites to experience graft failure (hazard ratio (HR) = 1.23, 95% confidence interval (CI) = 1.15-1.32), whereas Hispanics (HR = 0.77, 95% CI = 0.70-0.85) and Asians (HR = 0.70, 95% CI = 0.61-0.81) were less likely to experience graft failure. Blacks (HR = 0.84, 95% CI = 0.80-0.88), Hispanics (HR = 0.68, 95% CI = 0.64-0.72), and Asians (HR = 0.62, 95% CI = 0.57-0.68) were less likely than whites to die after renal transplantation.

CONCLUSION

Elderly blacks are at greater risk of graft failure than white transplant recipients but survive longer after transplantation. Asians have the highest recipient and graft survival, followed by Hispanics. Further studies are needed to assess additional factors affecting graft and recipient survival in elderly adults and to investigate outcomes such as quality of life.

Factors affecting willingness to receive a kidney transplant among minority patients at an urban safety-net hospital: a cross-sectional survey

Background

In the US, African Americans (AAs) are four times more likely to develop end stage renal disease (ESRD) but half as likely to receive a kidney transplant as whites. Patient interest in kidney transplantation is a fundamental step in the kidney transplant referral process. Our aim was to determine the factors associated with the willingness to receive a kidney transplant among chronic kidney disease (CKD) patients in a predominantly minority population.

Methods

CKD patients from an outpatient nephrology clinic at a safety-net hospital (n = 213) participated in a cross-sectional survey from April to June, 2013 to examine the factors associated with willingness to receive a kidney transplant among a predominantly minority population. The study questionnaire was developed from previously published literature. Multivariable logistic regression analysis was used to determine factors associated with willingness to undergo a kidney transplant.

Results

Respondents were primarily AAs (91.0 %), mostly female (57.6 %) and middle aged (51.6 %). Overall, 53.9 % of participants were willing to undergo a kidney transplant. Willingness to undergo a kidney transplant was associated with a positive perception towards living kidney donation (OR 7.31, 95 % CI: 1.31–40.88), willingness to attend a class about kidney transplant (OR = 7.15, CI: 1.76–29.05), perception that a kidney transplant will improve quality of life compared to dialysis (OR = 5.40, 95 % CI: 1.97–14.81), and obtaining information on kidney transplant from other sources vs. participant’s physician (OR =3.30, 95 % CI: 1.13–9.67), when compared with their reference groups.

Conclusion

It is essential that the quality of life benefits of kidney transplantation be known to individuals with CKD to increase their willingness to undergo kidney transplantation. Availability of multiple sources of information and classes on kidney transplantation may also contribute to willingness to undergo kidney transplantation, especially among AAs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0186-2) contains supplementary material, which is available to authorized users.

Race, Relationship and Renal Diagnoses After Living Kidney Donation

BACKGROUND

In response to recent studies, a better understanding of the risks of renal complications among African American and biologically related living kidney donors is needed.

METHODS

We examined a database linking U.S. registry identifiers for living kidney donors (1987-2007) to billing claims from a private health insurer (2000-2007 claims) to identify renal condition diagnoses categorized by International Classification of Diseases 9th Revision coding. Cox regression with left and right censoring was used to estimate cumulative incidence of diagnoses after donation and associations (adjusted hazards ratios, aHR) with donor traits.

RESULTS

Among 4650 living donors, 13.1% were African American and 76.3% were white; 76.1% were first-degree relatives of their recipient. By 7 years post-donation, after adjustment for age and sex, greater proportions of African American compared with white donors had renal condition diagnoses: chronic kidney disease (12.6% vs 5.6%; aHR, 2.32; 95% confidence interval [95% CI], 1.48-3.62), proteinuria (5.7% vs 2.6%; aHR, 2.27; 95% CI, 1.32-3.89), nephrotic syndrome (1.3% vs 0.1%; aHR, 15.7; 95% CI, 2.97-83.0), and any renal condition (14.9% vs 9.0%; aHR, 1.72; 95% CI, 1.23-2.41). Although first-degree biological relationship to the recipient was not associated with renal risk, associations of African American race persisted for these conditions and included unspecified renal failure and reported disorders of kidney dysfunction after adjustment for biological donor-recipient relationship.

CONCLUSIONS

African Americans more commonly develop renal conditions after living kidney donation, independent of donor-recipient relationship. Continued research is needed to improve risk stratification for renal outcomes among African American living donors.

Chronic Renal Transplant Rejection and Possible Anti-Proliferative Drug Targets

The global prevalence of renal transplants is increasing with time, and renal transplantation is the only definite treatment for end-stage renal disease. We have limited the acute and late acute rejection of kidney allografts, but the long-term survival of renal tissues still remains a difficult and unanswered question as most of the renal transplants undergo failure within a decade of their transplantation. Among various histopathological changes that signify chronic allograft nephropathy (CAN), tubular atrophy, fibrous thickening of the arteries, fibrosis of the kidney interstitium, and glomerulosclerosis are the most important. Moreover, these structural changes are followed by a decline in the kidney function as well. The underlying mechanism that triggers the long-term rejection of renal transplants involves both humoral and cell-mediated immunity. T cells, with their related cytokines, cause tissue damage. In addition, CD 20+ B cells and their antibodies play an important role in the long-term graft rejection. Other risk factors that predispose a recipient to long-term graft rejection include HLA-mismatching, acute episodes of graft rejection, mismatch in donor-recipient age, and smoking. The purpose of this review article is the analyze current literature and find different anti-proliferative agents that can suppress the immune system and can thus contribute to the long-term survival of renal transplants. The findings of this review paper can be helpful in understanding the long-term survival of renal transplants and various ways to improve it.

Patient-Centered mHealth Living Donor Transplant Education Program for African Americans: Development and Analysis

Background

There is a critical need to expand the pool of available kidneys for African Americans who are on the transplant wait-list due to the disproportionally lower availability of deceased donor kidneys compared with other races/ethnic groups. Encouraging living donation is one method to fill this need. Incorporating mHealth strategies may be a way to deliver educational and supportive services to African American transplant-eligible patients and improve reach to those living in remote areas or unable to attend traditional group-session-based programs. Before program development, it is essential to perform formative research with target populations to determine acceptability and cultivate a patient-centered and culturally relevant approach to be used for program development.

Objective

The objectives of this study were to investigate African American kidney transplant recipients’ and kidney donors’/potential donors’ attitudes and perceptions toward mobile technology and its viability in an mHealth program aimed at educating patients about the process of living kidney donation.

Methods

Using frameworks from the technology acceptance model and self-determination theory, 9 focus groups (n=57) were administered to African Americans at a southeastern medical center, which included deceased/living donor kidney recipients and living donors/potential donors. After a demonstration of a tablet-based video education session and explanation of a group-based videoconferencing session, focus groups examined members’ perceptions about how educational messages should be presented on topics pertaining to the process of living kidney donation and the transplantation. Questionnaires were administered on technology use and perceptions of the potential program communication platform. Transcripts were coded and themes were examined using NVivo 10 software.

Results

Qualitative findings found 5 major themes common among all participants. These included the following: (1) strong support for mobile technology use; (2) different media formats were preferred; (3) willingness to engage in video chats, but face-to-face interaction sometimes preferred; (4) media needs to be user friendly; (5) high prevalence of technology access. Our results show that recipients were willing to spend more time on education than the donors group, they wanted to build conversation skills to approach others, and preferred getting information from many sources, whereas the donor group wanted to hear from other living donors. The questionnaires revealed 85% or more of the sample scored 4+ on a 5-point Likert scale, which indicates high degree of interest to use the proposed program, belief that other mHealth technologies would help with adherence to medical regimens, and doctors would make regimen adjustments quicker. In addition, high utilization of mobile technology was reported; 71.9% of the participants had a mobile phone and 43.9% had a tablet.

Conclusions

Our study supports the use of an mHealth education platform for African Americans to learn about living donation. However, potential recipients and potential donors have differing needs, and therefore, programs should be tailored to each target audience.

Invariance of measures to understand decision-making for pursuing living donor kidney transplant

Living donor kidney transplant is the ideal treatment option for end-stage renal disease; however, the decision to pursue living donor kidney transplant is complex and challenging. Measurement invariance of living donor kidney transplant Decisional Balance and Self-Efficacy across gender (male/female), race (Black/White), and education level (no college/college or higher) were examined using a sequential approach. Full strict invariance was found for Decisional Balance and Self-Efficacy for gender and partial strict invariance was found for Decisional Balance and Self-Efficacy across race and education level. This information will inform tailored feedback based on these constructs in future intervention studies targeting behavior change among specific demographic subgroups.

Racial disparities in reaching the renal transplant waitlist: is geography as important as race?

BACKGROUND

In the United States, African Americans and whites differ in access to the deceased donor renal transplant waitlist. The extent to which racial disparities in waitlisting differ between United Network for Organ Sharing (UNOS) regions is understudied.

METHODS

The US Renal Data System (USRDS) was linked with US census data to examine time from dialysis initiation to waitlisting for whites (n = 188,410) and African Americans (n = 144,335) using Cox proportional hazards across 11 UNOS regions, adjusting for potentially confounding individual, neighborhood, and state characteristics.

RESULTS

Likelihood of waitlisting varies significantly by UNOS region, overall and by race. Additionally, African Americans face significantly lower likelihood of waitlisting compared to whites in all but two regions (1 and 6). Overall, 39% of African Americans with ESRD reside in Regions 3 and 4--regions with a large racial disparity and where African Americans comprise a large proportion of the ESRD population. In these regions, the African American-white disparity is an important contributor to their overall regional disparity.

CONCLUSIONS

Race remains an important factor in time to transplant waitlist in the United States. Race contributes to overall regional disparities; however, the importance of race varies by UNOS region.

Readiness of wait-listed black patients to pursue live donor kidney transplant

CONTEXT

For adults with end-stage kidney disease, live donor kidney transplant (LDKT) has better outcomes than long-term dialysis and deceased donor kidney transplant. However, black patients receive LDKT at a much lower rate than adults of any other race or ethnicity.

OBJECTIVE

To examine the LDKT readiness stage of black patients on the transplant waiting list and its association with LDKT knowledge, concerns, and willingness.

DESIGN

Cross-sectional analysis of baseline data from a randomized controlled trial to improve knowledge and reduce concerns about LDKT.Patients and Setting-One hundred fifty-two black patients on the kidney transplant waiting list at a single transplant center in the northeastern United States.

MAIN OUTCOME MEASURES

LDKT readiness stage, knowledge, concerns, and willingness to talk to others about living donation.

RESULTS

Sixty percent of patients were not considering or not yet ready to pursue LDKT, and only 11% had taken action to talk to family members or friends about the possibility of living kidney donation. Patients in later stages of LDKT readiness (ie, who had talked to others about donation or were preparing to do so) had significantly more knowledge (P<.001), fewer concerns (P=.002), and more willingness (P=.001) to talk to others about living donation than those in earlier readiness stages.

CONCLUSIONS

The large percentage of black patients who are in the earlier stages of LDKT readiness may account for the low rate of LDKT in this patient population at our transplant center. Innovative and tailored LDKT educational strategies for black patients are needed to help reduce racial disparities in LDKT.

The role of minority geographic distribution in waiting time for deceased donor kidney transplantation

In the US, African Americans and other minority groups have longer wait times to deceased donor kidney transplantation than Caucasians. To date, the role of geographic distribution of racial and ethnic groups as a determinant of wait times has not been fully elucidated. Using the Scientific Registry of Transplant Recipients database, all registrants for kidney transplant between 2004 and 2007 (n=126,094) were analyzed from time of waitlisting until nonzero antigen mismatched deceased donor kidney transplant. Nationally, deceased donor transplantation occurred at a lower rate for African Americans (hazard ratio [HR] 0.85, confidence interval [CI] 0.83-0.87), Hispanics (HR 0.68, CI 0.66-0.70), Asians/Pacific Islanders (HR 0.77, CI 0.73-0.80) and Other minority groups (HR 0.74, CI 0.69-0.81) compared to Caucasians. Multivariate modeling for age, gender, cause of end-stage renal disease, ABO type, panel reactive antibody, HLA-DR frequency, expanded criteria donor status and prior kidney donation only partially accounted for this difference. Adjusting for these variables and organ procurement organization of listing, African Americans (HR 1.03, CI 1.00-1.06), Hispanics (HR 1.15, CI 1.10-1.19), Asians/Pacific Islanders (HR 1.36, CI 1.30-1.43) and Other minority groups (HR 1.00, CI 0.92-1.09) were transplanted at similar or higher rates than Caucasians. Our findings show that geographic location of waitlisted candidates is the most important contributor to racial disparities in waiting times for deceased donor kidney transplantation.

The RaDIANT community study protocol: community-based participatory research for reducing disparities in access to kidney transplantation

BACKGROUND

The Southeastern United States has the lowest kidney transplant rates in the nation, and racial disparities in kidney transplant access are concentrated in this region. The Southeastern Kidney Transplant Coalition (SEKTC) of Georgia, North Carolina, and South Carolina is an academic and community partnership that was formed with the mission to improve access to kidney transplantation and reduce disparities among African American (AA) end stage renal disease (ESRD) patients in the Southeastern United States.

METHODS/DESIGN

We describe the community-based participatory research (CBPR) process utilized in planning the Reducing Disparities In Access to kidNey Transplantation (RaDIANT) Community Study, a trial developed by the SEKTC to reduce health disparities in access to kidney transplantation among AA ESRD patients in Georgia, the state with the lowest kidney transplant rates in the nation. The SEKTC Coalition conducted a needs assessment of the ESRD population in the Southeast and used results to develop a multicomponent, dialysis facility-randomized, quality improvement intervention to improve transplant access among dialysis facilities in GA. A total of 134 dialysis facilities are randomized to receive either: (1) standard of care or "usual" transplant education, or (2) the multicomponent intervention consisting of transplant education and engagement activities targeting dialysis facility leadership, staff, and patients within dialysis facilities. The primary outcome is change in facility-level referral for kidney transplantation from baseline to 12 months; the secondary outcome is reduction in racial disparity in transplant referral.

DISCUSSION

The RaDIANT Community Study aims to improve equity in access to kidney transplantation for ESRD patients in the Southeast.

TRIAL REGISTRATION

Clinicaltrials.gov number NCT02092727.

Prospective randomized controlled trial of rabbit antithymocyte globulin compared with IL-2 receptor antagonist induction therapy in kidney transplantation

OBJECTIVE

The aim of this study was to determine the safety and efficacy of induction with rabbit antithymocyte globulin (RATG) compared with interleukin-2 receptor antagonists in a racially diverse kidney transplant patient population under modern immunosuppression.

BACKGROUND

The optimal induction therapy in patients at risk for rejection, particularly black recipients, in the modern era of immunosuppression with flow cytometry-based cross-matching is unclear.

METHODS

This was a prospective, risk-stratified, randomized, single-center, open-label study of 200 consecutively enrolled patients in a large academic teaching center. Patients were randomized to receive either daclizumab or basiliximab versus RATG for induction in combination with tacrolimus, mycophenolate mofetil, and corticosteroids. Patients were stratified between groups to ensure equal numbers of black, retransplants, high panel reactive antibodies (PRAs) (>20%), and prolonged cold ischemic times (>24 hours) in each group. Primary outcome measure is treatment efficacy defined as the incidence of biopsy-proven acute rejection and estimated creatinine clearance. Patients were followed up for 12 months. Renal transplant recipients were included if they were adult (≥18 years old) and received an allograft from a deceased, living unrelated, or nonhuman leukocyte antigen identical living-related donor.

RESULTS

A total of 200 patients (n = 98 in the interleukin-2 receptor antagonists, and n = 102 in the RATG) were enrolled from February 2009 through July 2011. One-year acute rejection rates were low and similar between groups (10% in the interleukin-2 receptor antagonist group vs 6% in the RATG group; P = 0.30). Creatinine clearance was also similar between groups (interleukin-2 receptor antagonist group 56 ± 20 mL/min per 1.73 m2 vs RATG group 55 ± 22 mL/min per 1.73 m2; P = 0.73). Subanalysis of recipient race revealed that in blacks only RATG was protective against 6- and 12-month acute rejection, without an increased risk of infection. Induction did not affect rejection rates according to recipient calculated PRAs; however, RATG was associated with an increased risk of BK virus in low-PRA patients.

CONCLUSIONS AND RELEVANCE

RATG induction provides improved protection against early acute rejection in black renal transplant recipients, whereas sensitized patients do not seem to demonstrate a similar benefit from this therapy. This study is registered at Clinicaltrials.gov (NCT00859131).

APOL1 polymorphisms and development of CKD in an identical twin donor and recipient pair

We report an occurrence of progressive loss of transplant function and ultimately transplant failure after living related kidney transplantation involving monozygotic twin brothers of Afro-Caribbean origin who were both heterozygous for the G1 and G2 kidney disease risk alleles in the APOL1 gene, which encodes apolipoprotein L-I. A 21-year-old man with end-stage kidney disease of unknown cause received a kidney from his brother, who was confirmed as a monozygotic twin by microsatellite analysis. Thirty months after transplantation, the patient presented with proteinuria and decreased estimated glomerular filtration rate; a biopsy of the transplant showed typical focal segmental glomerulosclerosis lesions. He received steroid therapy, but progressed to kidney failure 5 years later. The twin brother had normal kidney function without proteinuria at the time of transplantation; however, 7 years later, he was found to have decreased estimated glomerular filtration rate (40mL/min/1.73m(2)) and proteinuria (protein excretion of 2.5g/d). APOL1 genotyping revealed that both donor and recipient were heterozygous for the G1 and G2 alleles. This case is in stark contrast to the expected course of kidney transplantation in identical twins and suggests a role for APOL1 polymorphisms in both the donor and recipient.

The risk of acute rejection and the influence of induction agents in lower-risk African American kidney transplant recipients receiving modern immunosuppression

BACKGROUND

While kidney transplant recipients of African American (AA) descent are frequently considered at increased risk of acute rejection, the value of induction therapy is not defined in settings of lower immunologic risk and modern immunosuppression.

METHODS

Using the Scientific Registry of Transplant Recipients database, we identified 23,244 primary kidney transplant recipients with panel-reactive antibody (PRA) = 0% treated with TAC/MPA and prednisone from 2000 to 2008. We compared acute rejection, graft survival (GS), and patient survival rates among AA and non-AA and further stratified by induction therapy (none, IL2ra, or rATG).

RESULTS

One-yr acute rejection was higher in AA than in non-AA overall (14.5% vs. 9.9%, hazard ratio [HR] for acute rejection [AR] 1.43, p < 0.0001) and was higher regardless of induction agent use. Induction therapy was associated with a reduction in AR, but no benefit in GS in AA or non-AA. In AA, rATG (adjusted relative risk [RR] 0.81, CI 0.70-0.94) and IL2ra (adjusted RR 0.80, CI 0.68-0.93) were similarly effective in reducing AR rates, but did not reach comparable outcomes as in non-AA.

CONCLUSION

African Americans who are at otherwise lower immunologic risk have a higher risk of rejection despite modern immunosuppression. Depleting or non-depleting induction therapy similarly reduces but does not entirely mitigate this increased risk, with no impact on three-yr GS.

How is organ transplantation depicted in internal medicine and transplantation journals

BACKGROUND

In their book Spare Parts, published in 1992, Fox and Swazey criticized various aspects of organ transplantation, including the routinization of the procedure, ignorance regarding its inherent uncertainties, and the ethos of transplant professionals. Using this work as a frame of reference, we analyzed articles on organ transplantation published in internal medicine and transplantation journals between 1995 and 2008 to see whether Fox and Swazey's critiques of organ transplantation were still relevant.

METHODS

Using the PubMed database, we retrieved 1,120 articles from the top ten internal medicine journals and 4,644 articles from the two main transplantation journals (Transplantation and American Journal of Transplantation). Out of the internal medicine journal articles, we analyzed those in which organ transplantation was the main topic (349 articles). A total of 349 articles were randomly selected from the transplantation journals for content analysis.

RESULTS

In our sample, organ transplantation was described in positive terms and was presented as a routine treatment. Few articles addressed ethical issues, patients' experiences and uncertainties related to organ transplantation. The internal medicine journals reported on more ethical issues than the transplantation journals. The most important ethical issues discussed were related to the justice principle: organ allocation, differential access to transplantation, and the organ shortage.

CONCLUSION

Our study provides insight into representations of organ transplantation in the transplant and general medical communities, as reflected in medical journals. The various portrayals of organ transplantation in our sample of articles suggest that Fox and Swazey's critiques of the procedure are still relevant.

Low C-reactive protein levels in a traditional West-African population living in a malaria endemic area

Background

C-reactive protein (CRP) levels are reported to be elevated in populations of African descent living in affluent environments compared to populations of European ancestry. However, the natural history of CRP levels in populations of African descent living under adverse environments remains largely unknown.

Methods

CRP levels were measured with a high sensitivity assay in 624 apparently healthy individuals who contributed blood as part of a study on innate immune responsiveness in a traditional Ghanaian population living under adverse environmental conditions in a malaria endemic area. As a comparison, we included CRP measurements from 2931 apparently healthy individuals from the Dutch population that were included in the same batch of CRP analyses. Associations between CRP and body mass index (BMI), immune responsiveness, and P. falciparum parasitaemia were investigated.

Results

In an age- and sex-adjusted model, CRP levels were 0.54 mg/L lower in the Ghanaian compared to the Dutch cohort (1.52 vs. 0.98 mg/L, p<0.001). When accounting for the substantially higher average BMI in the Dutch compared to the Ghanaians (25.6 vs. 18.4 kg/m²) the difference in CRP levels disappeared. BMI associated positively with CRP in the Dutch but not in the Ghanaians. In individuals with an acute phase response, CRP levels were higher in the Ghanaian compared to the Dutch cohort (24.6 vs. 17.3 mg/L, p = 0.04). Levels of CRP were positively related to immune responsiveness and P. falciparum parasitaemia (all p<0.001) among Ghanaians.

Conclusions

Our study demonstrates that West-Africans do not exhibit an inherently high inflammatory state. The role of genes, environment and gene-environment interaction in explaining reports of elevated CRP levels in populations of African ancestry when compared to other ethnicities living in affluent environments thus merits further investigation.

Evaluation of living kidney donors: variables that affect donation

Approximately 10000 deceased donor organs are available yearly for 85 000 US patients awaiting kidney transplant. Living kidney donation is essential to close this gap and offers better survival rates. However, nationally, 80% of potential donors evaluated fail to donate. Nurse coordinators who perform predonation screening and education need additional insight into the large number of potential donors who fail to complete the donation process. Reasons for nondonation in donor candidates undergoing medical evaluation, and variables affecting nondonation at Vanderbilt University Medical Center between 2004 and 2009 are examined. Multivariable logistic regression models are used to test the effects of age and race on donation status and reasons for nondonation. Summary data are frequencies, percentages, and means (SD). The sample included 706 candidates (63% female, 80% white; mean age, 40 [SD, 12] years). Almost half (46%) received clearance to donate. Undiagnosed hypertension (14%), abnormal glucose tolerance (10%), and protein-urea (9%) were the most prevalent medical reasons for nondonation. About 13% of candidates changed their minds during evaluation. Analyses demonstrated an increased likelihood of older candidates (P < .001) and a decreased likelihood of white candidates (P = .007) being excluded from donation. Within the nondonation group, increased age was associated with undiagnosed hypertension and abnormal glucose tolerance (both race-adjusted, P = .01). Younger candidates (race-adjusted, P = .003) and African Americans (age-adjusted, P = .04) were more likely to decide against donation. The most prevalent medical reasons for nondonation could be identified through enhanced prescreening, and improved preevaluation education could decrease nondonation rates.

Sirolimus pharmacokinetics in early postmyeloablative pediatric blood and marrow transplantation

This study examined the pharmacokinetics of sirolimus in pediatric allogeneic blood and marrow transplantation (BMT) recipients in the presence and absence of concomitant fluconazole. Forty pediatric BMT recipients received a daily oral dose of sirolimus and a continuous i.v. infusion of tacrolimus for graft-versus-host disease prophylaxis. Fluconazole was administered i.v. to 19 patients and orally to 6 patients. Full pharmacokinetic profiles of sirolimus within a single dosing interval were collected. Whole-blood sirolimus concentrations were measured by HPLC/mass spectrometry. Noncompartmental analysis was performed using WinNonlin. Nonlinear mixed-effects pharmacokinetic models were developed using NONMEM following standard procedures. The mean ± SD sirolimus trough level before the dose (C0) was 8.0 ± 4.6 ng/mL (range, 1.8-21.6 ng/mL). The peak concentration was 19.9 ± 11.8 ng/mL (range, 3.9-46.1 ng/mL), and the trough level 24 hours later (C24) was 9.1 ± 5.3 ng/mL (range, 1.0-19.1 ng/mL). The terminal disposition half-life (T1/2) was 24.5 ± 11.2 hours (range, 5.8-53.2 hours), and the area under the concentration-versus-time curve (AUC0-24) was 401.1 ± 316.3 ng·h/mL (range, 20.7-1332.3 ng·h/mL). In patients at steady state, C0 and C24 were closely correlated (R(2) = 0.77) with a slope of 0.99, indicating the achievement of steady state. C24 was 1.7-fold greater (P = .036) and AUC0-24 was 2-fold greater (P = .012) in Caucasian patients (n = 22) compared with Hispanic patients (n = 9). The average apparent oral clearance was 3-fold greater (P = .001) and the apparent oral volume of distribution was 2-fold greater (P = .018) in patients age ≤12 years compared with those age >12 years. C24 was significantly lower in patients (n = 10) who developed grade III-IV aGVHD (n = 10) than in those with grade 0-II aGVHD (n = 22) (6.1 ± 2.9 ng/mL versus 9.4 ± 5.5 ng/mL; P = .044). Dose-normalized sirolimus trough concentrations were significantly higher in patients receiving concomitant fluconazole therapy compared with those not receiving fluconazole (C0: 3.9 ± 2.5 versus 2.4 ± 1.5 ng/mL/mg, P = .030; C24: 4.8 ± 3.3 versus 2.5 ± 1.7 ng/mL/mg, P = .018). This pharmacokinetic study of sirolimus in pediatric patients documents a large interindividual variability in the exposure of sirolimus. Steady-state trough blood concentrations were correlated with drug exposure. Trough concentrations were higher with a concomitant use of fluconazole and were higher in Caucasian patients than in Hispanic patients. Oral clearance was greater in children age ≤12 years than in older children and adolescents. With therapeutic drug monitoring, the majority (79%) of sirolimus trough levels could be maintained within the target range (3-12 ng/mL). This study provides a rationale and support for dose adjustments of sirolimus based on steady-state blood concentrations aimed at achieving a target concentration to minimize toxicity and maximize therapeutic benefits in pediatric BMT recipients.

Risk of end-stage renal disease among liver transplant recipients with pretransplant renal dysfunction

Guidelines recommend restricting simultaneous liver-kidney (SLK) transplant to candidates with prolonged dialysis or estimated glomerular filtration rate (eGFR) <30 mL/min/1.73m(2) for 90 days. However, few studies exist to support the latter recommendation. Using Scientific Registry of Transplant Recipients and Medicare dialysis data, we assembled a cohort of 4997 liver transplant recipients from February 27, 2002-January 1, 2008. Serial eGFRs were calculated from serum creatinines submitted with MELD reports. We categorized recipients by eGFR patterns in the 90 days pretransplant: Group 1 (eGFR always >30), Group 2 (eGFR fluctuated), Group 3 (eGFR always <30) and Group 4 (short-term dialysis). For Group 2, we characterized fluctuations in renal function using time-weighted mean eGFR. Among liver-alone recipients in Group 3, the rate of end-stage renal disease (ESRD) by 3 years was 31%, versus <10% for other groups (p < 0.001). In multivariable Cox regression, eGFR Group, diabetes (HR 2.65, p < 0.001) and black race (HR 1.83, p = 0.02) were associated with ESRD. Among liver-alone recipients in Group 2, only diabetics with time-weighted mean eGFR <30 had a substantial ESRD risk (25.6%). In summary, among liver transplant candidates not on prolonged dialysis, SLK should be considered for those whose eGFR is always <30 and diabetic candidates whose weighted mean eGFR is <30 for 90 days.

Association between residence location and likelihood of transplantation among pediatric dialysis patients

Many children with ESRD reside far from a kidney transplant center. It is unknown whether this geographical barrier affects likelihood of transplantation. We used data from a national ESRD database. Patients ≤ 18 yr old who started renal replacement in nine Canadian provinces during 1992-2007 were followed until death or last contact. Primary outcome was kidney transplantation (living or deceased donor). Distance between nearest pediatric transplant center and each patient's residence was categorized as: <50, 50 to <150, 150 to <300, and ≥ 300 km. Using survival analysis, we compared likelihood of transplantation between whites and non-whites living in various distance categories. Among 728 patients, 52.2% were males and 62.5% were whites. Compared to white children living < 50 km from a transplant center, white (HR, 0.73; 95% CI, 0.56-0.95) and non-white (HR, 0.66; 95% CI, 0.48-0.92) children living ≥ 300 km away were less likely to receive a transplant. Non-white children living < 50 km away (HR, 0.59; 95% CI 0, 45-0.78) were also less likely to receive a transplant compared to otherwise similar whites living < 50 km away. Although equitable access to transplantation by residence location is observed among remote-dwelling adults with ESRD, white and non-white children with ESRD living ≥ 300 km from a transplant center were less likely to receive transplants.

Feasibility and acceptability of the TALK social worker intervention to improve live kidney transplantation

Live kidney transplantation (LKT) is underused by patients with end-stage renal disease. Easily implementable and effective interventions to improve patients' early consideration of LKT are needed. The Talking About Live Kidney Donation (TALK) social worker intervention (SWI) improved consideration and pursuit of LKT among patients with progressive chronic kidney disease in a recent randomized controlled trial: Patients and their families were invited to meet twice with a social worker to discuss their self-identified barriers to seeking LKT and to identify solutions to barriers. The authors audio recorded and transcribed all social worker visits to assess implementation of the TALK SWI and its acceptability to patients and families. The study social worker adhered to the TALK SWI protocol more than 90 percent of the time. Patients and families discussed medical (for example, long-term risks of transplant), psychological (for example, patients' denial of the severity of their disease), and economic (for example, impact of donation on family finances) concerns regarding LKT. Most patients and families felt that the intervention was helpful. Consistently high adherence to the TALK SWI protocol and acceptability of the intervention among patients and families suggest that the TALK SWI can be feasibly implemented in clinical practice.

The providing resources to enhance African American patients' readiness to make decisions about kidney disease (PREPARED) study: protocol of a randomized controlled trial

Background

Living related kidney transplantation (LRT) is underutilized, particularly among African Americans. The effectiveness of informational and financial interventions to enhance informed decision-making among African Americans with end stage renal disease (ESRD) and improve rates of LRT is unknown.

Methods/design

We report the protocol of the Providing Resources to Enhance African American Patients’ Readiness to Make Decisions about Kidney Disease (PREPARED) Study, a two-phase study utilizing qualitative and quantitative research methods to design and test the effectiveness of informational (focused on shared decision-making) and financial interventions to overcome barriers to pursuit of LRT among African American patients and their families. Study Phase I involved the evidence-based development of informational materials as well as a financial intervention to enhance African American patients’ and families’ proficiency in shared decision-making regarding LRT. In Study Phase 2, we are currently conducting a randomized controlled trial in which patients with new-onset ESRD receive 1) usual dialysis care by their nephrologists, 2) the informational intervention (educational video and handbook), or 3) the informational intervention in addition to the option of participating in a live kidney donor financial assistance program. The primary outcome of the randomized controlled trial will include patients’ self-reported rates of consideration of LRT (including family discussions of LRT, patient-physician discussions of LRT, and identification of a LRT donor).

Discussion

Results from the PREPARED study will provide needed evidence on ways to enhance the decision to pursue LRT among African American patients with ESRD.

Trial registration

ClinicalTrials.gov NCT01439516

Review of ethnic disparities in access to renal transplantation

Renal transplantation is the gold standard treatment for patients with end-stage renal disease and is associated with several advantages over dialysis, including increased quality of life, reduced morbidity and mortality, and lower healthcare costs. Barring the constraints of a limited organ supply, the goals of the patient care should focus on attaining renal transplantation while minimizing, or even eliminating, time spent on dialysis. Disparities in access to renal transplantation between African Americans and Caucasians have been extensively documented, with African Americans having significantly poorer access. There is a growing corpus of literature examining the determinants of reduced access among other racial ethnic minority groups, including Hispanics. These determinants include patient and physician preference, socioeconomic status, insurance type, patient education, and immunologic factors. We review these determinants in access to renal transplantation in the United States among all races and ethnicities.

Influence of race, ethnicity and socioeconomic status on kidney disease

Low socioeconomic status (SES) influences disease incidence and contributes to poor health outcomes throughout an individual's life course across a wide range of populations. Low SES is associated with increased incidence of chronic kidney disease, progression to end-stage renal disease, inadequate dialysis treatment, reduced access to kidney transplantation, and poor health outcomes. Similarly, racial and ethnic disparities, which in the USA are strongly associated with lower SES, are independently associated with poor health outcomes. In this Review, we discuss individual-level and group-level SES factors, and the concomitant role of race and ethnicity that are associated with and mediate the development of chronic kidney disease, progression to end-stage renal disease and access to treatment.

The Impact of Medicare's lifetime immunosuppression coverage on racial disparities in kidney graft survival

Beginning January 1, 2000, Medicare effectively extended its coverage of immunosuppression medications from 3 years to lifetime for patients eligible for Medicare on the basis of age or disability status. We examined the impact of this policy on racial disparities in kidney transplant outcomes at 5 years. Using data from the US Renal Data System, we identified cohorts of Medicare-insured kidney transplant recipients according to patient characteristics defining eligibility for lifetime immunosuppression coverage according to the year 2000 policy. We compared racial disparities in graft survival among those eligible for lifetime coverage with the Kaplan-Meier method. We modeled adjusted associations of patient race, patient income, benefits eligibility category and policy exposure with graft loss by multivariable Cox's regression. The racial disparity in graft survival between African American and non-African American among transplant recipients eligible for the lifetime benefit persisted. The graft survival disparity between high- and low-income African American recipients was insignificantly reduced among those eligible for the lifetime benefit. The results of the study suggest that insurance coverage of medication did not eliminate or reduce the racial disparity in graft survival.

Perceived discrimination predicts longer time to be accepted for kidney transplant

BACKGROUND

Although end-stage kidney disease in African Americans (AAs) is four times greater than in whites, AAs are less than one half as likely to undergo kidney transplantation (KT). This racial disparity has been found even after controlling for clinical factors such as comorbid conditions, dialysis vintage and type, and availability of potential living donors. Therefore, studying nonmedical factors is critical to understanding disparities in KT.

METHODS

We conducted a longitudinal cohort study with 127 AA and white patients with end-stage kidney disease undergoing evaluation for KT (December 2006 to July 2007) to determine whether, after controlling for medical factors, differences in time to acceptance for transplant is explained by patients' cultural factors (e.g., perceived racism and discrimination, medical mistrust, religious objections to living donor KT), psychosocial characteristics (e.g., social support, anxiety, depression), or transplant knowledge. Participants completed two telephone interviews (shortly after initiation of transplant evaluation and after being accepted or found ineligible for transplant).

RESULTS

Results indicated that AA patients reported higher levels of the cultural factors than did whites. We found no differences in comorbidity or availability of potential living donors. AAs took significantly longer to get accepted for transplant than did whites (hazard ratio=1.49, P=0.005). After adjustment for demographic, psychosocial, and cultural factors, the association of race with longer time for listing was no longer significant.

CONCLUSIONS

We suggest that interventions to address racial disparities in KT incorporate key nonmedical risk factors in patients.

The "House Calls" trial: a randomized controlled trial to reduce racial disparities in live donor kidney transplantation: rationale and design

Despite a substantially lower rate of live donor kidney transplantation among Black Americans compared to White Americans, there are few systematic efforts to reduce this racial disparity. This paper describes the rationale and design of a randomized controlled trial evaluating the comparative effectiveness of three different educational interventions for increasing live donor kidney transplantation in Black Americans. This trial is a single-site, urn-randomized controlled trial with a planned enrollment of 180 Black Americans awaiting kidney transplantation. Patients are randomized to receive transplant education in one of three education conditions: through group education at their homes (e.g., House Calls), or through group (Group-Based) or individual education (Individual Counseling) in the transplant center. The primary outcome of the trial is the occurrence of a live donor kidney transplant, with secondary outcomes including living donor inquiries and evaluations as well as changes in patient live donor kidney transplantation readiness, willingness, knowledge, and concerns. Sex, age, dialysis status, and quality of life are evaluated as moderating factors. Findings from this clinical trial have the potential to inform strategies for reducing racial disparities in live donor kidney transplantation. Similar trials have been developed recently to broaden the evaluation of House Calls as an innovative disparity-reducing intervention in kidney transplantation.

Implications of a positive crossmatch in liver transplantation: a 20-year review

Whether a positive crossmatch result has any relevance to liver transplantation (LT) outcomes remains controversial. We assessed the impact of a positive crossmatch result on patient and graft survival and posttransplant complications. During a 20-year period, 2723 LT procedures with crossmatch results were identified: 2479 primary transplants and 244 retransplants. The rates of positive B cell and T cell crossmatches were 10.1% and 7.4%, respectively, for primary transplants and 14.6% and 6.4%, respectively, for retransplants (P = 0.049 for a B cell crossmatch). Across all primary transplants, females (P < 0.001) and patients with autoimmune hepatitis (P < 0.001) had greater frequencies of positive crossmatches. There was no effect from race or age. For both primary transplants and retransplants, patient survival and graft survival were not affected by the presence of a positive crossmatch. With respect to posttransplant complications, there were no differences in rejection episodes (hyperacute, acute, or chronic) or technical complications (biliary and vascular) between negative and positive crossmatch groups. However, there were significant differences in the pathological findings of preservation injury (PI) on liver biopsy samples taken at the time of transplantation and within the first week of transplantation (P = 0.003 for B cells and P = 0.03 for T cells). In summary, a positive crossmatch had no significant impact on patient survival or graft outcomes. However, there was a significantly higher incidence of PI in primary LT recipients with a positive crossmatch. This finding is important for a broader understanding of PI, which may include a significant immunological component.

Immune factors influencing ethnic disparities in kidney transplantation outcomes

An influence of ethnicity on the outcomes of kidney transplant recipients has been recognized for several decades. Both immune and nonimmune factors have been explored as potential explanations. Most studies have focused on the inferior outcomes of African-Americans. As a group, African-Americans differ from Caucasians with respect to a number of measurable components of the alloimmune response, including the T-cell repertoire and the expression and function of costimulatory molecules and various cytokines and chemokines. In general, these differences suggest that African-Americans may be high immune responders. However, no single difference in any of these components of alloimmunity satisfactorily explains the disparities in outcomes. It seems probable that some combination of immune factors interacts with nonimmune factors, such as socioeconomic resources, to influence transplant outcomes in a complex manner.

Racial disparities in pediatric access to kidney transplantation: does socioeconomic status play a role?

Racial disparities persist in access to renal transplantation in the United States, but the degree to which patient and neighborhood socioeconomic status (SES) impacts racial disparities in deceased donor renal transplantation access has not been examined in the pediatric and adolescent end-stage renal disease (ESRD) population. We examined the interplay of race and SES in a population-based cohort of all incident pediatric ESRD patients <21 years from the United States Renal Data System from 2000 to 2008, followed through September 2009. Of 8452 patients included, 30.8% were black, 27.6% white-Hispanic, 44.3% female and 28.0% lived in poor neighborhoods. A total of 63.4% of the study population was placed on the waiting list and 32.5% received a deceased donor transplant. Racial disparities persisted in transplant even after adjustment for SES, where minorities were less likely to receive a transplant compared to whites, and this disparity was more pronounced among patients 18-20 years. Disparities in access to the waiting list were mitigated in Hispanic patients with private health insurance. Our study suggests that racial disparities in transplant access worsen as pediatric patients transition into young adulthood, and that SES does not explain all of the racial differences in access to kidney transplantation.

Early pancreas graft failure is associated with inferior late clinical outcomes after simultaneous kidney-pancreas transplantation

BACKGROUND

Early pancreas graft failure after simultaneous pancreas and kidney (SPK) transplantation is common. We studied the impact of early pancreas graft failure on long-term kidney and patient survival.

METHODS

We included all primary SPK transplants performed in the United States between January 1, 2000, and December 31, 2007, who had maintained kidney graft function at 90 days posttransplantation. Kaplan-Meier and Cox multivariate analyses were performed. The causes of death between the two cohorts were compared.

RESULTS

A total of 6282 SPK recipients were included in the analyses. Of those, 470 had lost pancreas graft within the first 90 days largely related to pancreas graft thrombosis. Early pancreas graft failure was associated with lower subsequent kidney graft and patient survival (log-rank, P=0.02 and P<0.001, respectively). Multivariate regression analyses demonstrated a 70% higher risk of kidney graft failure after 3 years (adjusted hazard ratio 1.69; 95% CI 1.08, 2.66; P=0.022) and more than doubled the risk for death (adjusted hazard ratio 2.18; 95% CI 1.67, 2.85; P<0.001) among SPK recipients with early pancreas graft failure. The causes of death were similar between the two cohorts.

CONCLUSION

Early pancreas graft failure in SPK transplant recipients is associated with an increased risk for subsequent kidney failure and death. Optimization of therapeutic interventions after early pancreas graft failure is needed.

A review of utility-based allocation strategies to maximize graft years of deceased donor kidneys

With the continuing shortage of deceased donor kidneys coupled with a growing number of older potential recipients, there has been a greater acceptance of using older donor kidneys, including increased utility of expanded criteria donor (ECD) kidneys. In this review, we will look at the impact of using ECD kidneys on graft and patient survival, and to identify modifiable factors that may improve transplant outcomes in recipients receiving ECD kidneys. In addition, we will discuss whether the implementation of utility-based allocation strategies to maximize graft outcomes is an appropriate way forward to provide a better balance between utility and equity in the distribution of deceased donor kidneys.

Assessment of variation in live donor kidney transplantation across transplant centers in the United States

BACKGROUND

Transplant centers vary in the proportion of kidney transplants performed using live donors. Clinical innovations that facilitate live donation may drive this variation.

METHODS

We assembled a cohort of renal transplant candidates at 194 US centers using registry data from 1999 to 2005. We measured magnitude of live donor kidney transplantation (LDKTx) through development of a standardized live donor transplantation ratio (SLDTR) at each center that accounted for center population differences. We examined associations between center characteristics and the likelihood that individual transplant candidates underwent LDKTx. To identify practices through which centers increase LDKTx, we also examined center characteristics associated with consistently being in the upper three quartiles of SLDTR.

RESULTS

The cohort comprised 148,168 patients, among whom 34,593 (23.3%) underwent LDKTx. In multivariable logistic regression, candidates had an increased likelihood of undergoing LDKTx at centers with greater use of "unrelated donors" (defined as nonspouses and nonfirst-degree family members of the recipient; odds ratio [OR] 1.31 for highest vs. lowest use; P=0.02) and at centers with programs to overcome donor-recipient incompatibility (OR 1.33; P=0.01). Centers consistently in the upper three SLDTR quartiles were also more likely to use "unrelated" donors (OR 8.30 per tertile of higher use; P<0.01), to have incompatibility programs (OR 4.79, P<0.01), and to use laparoscopic nephrectomy (OR 2.53 per tertile of higher use; P=0.02).

CONCLUSION

Differences in center population do not fully account for differences in the use of LDKTx. To maximize opportunities for LDKTx, centers may accept more unrelated donors and adopt programs to overcome biological incompatibility.

Association of race and age with survival among patients undergoing dialysis

CONTEXT

Many studies have reported that black individuals undergoing dialysis survive longer than those who are white. This observation is paradoxical given racial disparities in access to and quality of care, and is inconsistent with observed lower survival among black patients with chronic kidney disease. We hypothesized that age and the competing risk of transplantation modify survival differences by race.

OBJECTIVE

To estimate death among dialysis patients by race, accounting for age as an effect modifier and kidney transplantation as a competing risk.

DESIGN, SETTING, AND PARTICIPANTS

An observational cohort study of 1,330,007 incident end-stage renal disease patients as captured in the United States Renal Data System between January 1, 1995, and September 28, 2009 (median potential follow-up time, 6.7 years; range, 1 day-14.8 years). Multivariate age-stratified Cox proportional hazards and competing risk models were constructed to examine death in patients who receive dialysis.

MAIN OUTCOME MEASURES

Death in black vs white patients who receive dialysis.

RESULTS

Similar to previous studies, black patients undergoing dialysis had a lower death rate compared with white patients (232,361 deaths [57.1% mortality] vs 585,792 deaths [63.5% mortality], respectively; adjusted hazard ratio [aHR], 0.84; 95% confidence interval [CI], 0.83-0.84; P <.001). However, when stratifying by age and treating kidney transplantation as a competing risk, black patients had significantly higher mortality than their white counterparts at ages 18 to 30 years (27.6% mortality vs 14.2%; aHR, 1.93; 95% CI, 1.84-2.03), 31 to 40 years (37.4% mortality vs 26.8%; aHR, 1.46; 95% CI, 1.41-1.50), and 41 to 50 years (44.8% mortality vs 38.0%; aHR, 1.12; 95% CI, 1.10-1.14; P <.001 for interaction terms between race and each aforementioned age category), as opposed to patients aged 51 to 60 years (51.5% vs 50.9%; aHR, 0.93; 95% CI, 0.92-0.94), 61 to 70 years (64.9% vs 67.2%; aHR, 0.87; 95% CI, 0.86-0.88), 71 to 80 years (76.1% vs 79.7%; aHR, 0.85; 95% CI, 0.84-0.86), and older than 80 years (82.4% vs 83.6%; aHR, 0.87; 95% CI, 0.85-0.88).

CONCLUSIONS

Overall, among dialysis patients in the United States, there was a lower risk of death for black patients compared with their white counterparts. However, the commonly cited survival advantage for black dialysis patients applies only to older adults, and those younger than 50 years have a higher risk of death.

Effect of eliminating priority points for HLA-B matching on racial disparities in kidney transplant rates

BACKGROUND

African Americans have lower rates of obtaining a deceased donor kidney transplant (DDKT) compared with their white counterparts. One proposed mechanism is differential HLA distributions between African Americans and whites. In May 2003, the United Network for Organ Sharing/Organ Procurement and Transplantation Network changed kidney allocation policy to eliminate priority based on HLA-B matching in an effort to address this disparity. The objective of this study was to quantify the effect of the change in policy regarding priority points for HLA-B matching.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

A cohort of 178,902 patients registered for a DDKT between January 2000 and August 2009.

FACTORS

African Americans versus whites before and after the policy change. Cox models were adjusted for age, sex, diabetes, dialysis type, insurance status, education, panel-reactive antibody level, and blood type.

OUTCOMES

Adjusted relative rates (aRRs) of deceased donor kidney transplant for African Americans compared with whites.

MEASUREMENTS

Time from initial active wait listing to DDKT, censored for living donor kidney transplant and death.

RESULTS

Before the policy change, African Americans had 37% lower rates of DDKT (aRR, 0.63; 95% CI, 0.60-0.65; P < 0.001). After the policy change, African Americans had 23% lower rates of DDKT (aRR, 0.77; 95% CI, 0.76-0.79; P < 0.001). There was a 23% reduction in the disparity between African Americans and whites after the policy change (interaction aRR, 1.23; 95% CI, 1.18-1.29; P < 0.001).

LIMITATIONS

As an observational study, findings could have been affected by residual confounding or other changes in practice patterns.

CONCLUSIONS

Racial disparity in rates of DDKT was decreased by the HLA-B policy change, but parity was not achieved. There are unaddressed factors in kidney allocation that lead to continued disparity on the kidney transplant waiting list.

Paired kidney donor exchanges and antibody reduction therapy: novel methods to ameliorate disparate access to living donor kidney transplantation in ethnic minorities

BACKGROUND

Currently ethnic minority patients comprise 60% of patients listed for kidney transplantation in the US; however, they receive only 55% of deceased donor renal transplants and 25% of living donor renal transplants. Ethnic disparities in access to kidney transplantation result in increased morbidity and mortality for minority patients with end-stage renal disease. Because these patients remain dialysis dependent for longer durations, they are more prone to the development of HLA antibodies that further delay the possibility of receiving a successful kidney transplant.

STUDY DESIGN

Two to 4 pretransplant and post-transplant plasma exchanges and i.v. immunoglobulin were used to lower donor-specific antibody levels to less than 1:16 dilution; cell lytic therapy was used additionally in some cases. Match pairing by virtual cross-matching was performed to identify the maximal exchange benefit. Sixty candidates for renal transplantation were placed into 4 paired kidney exchanges and/or underwent antibody reduction therapy.

RESULTS

Sixty living donor renal transplants were performed by paired exchange pools and/or antibody reduction therapy in recipients whose original intended donors had ABO or HLA incompatibilities or both (24 desensitization and 36 paired kidney exchanges). Successful transplants were performed in 38 ethnic minorities, of which 33 were African American. Twenty-two recipients were white. Graft and patient survival was 100% at 6 months; graft function (mean serum creatinine 1.4 g/dL) and acute rejection rates (20%) have been comparable to traditional live donor kidney transplantation.

CONCLUSIONS

Paired kidney donor exchange pools with antibody reduction therapy can allow successful transplant in difficult to match recipients. This approach can address kidney transplant disparities.

Herpes zoster incidence in a multicenter cohort of solid organ transplant recipients

BACKGROUND

Immunosuppressed patients are at increased risk for herpes zoster (HZ), but incidence in solid organ transplant (SOT) recipients has varied in multiple studies. To assess incidence of HZ, we examined patients who underwent SOT and received follow-up care within the large multicenter US Department of Veteran's Affairs healthcare system.

METHODS

Incident cases of HZ were determined using ICD-9 coding from administrative databases. A multivariable Cox proportional hazards model, adjusted for a priori risk factors, was used to assess demographic factors associated with development of HZ.

RESULTS

Among the 1077 eligible SOT recipients, the cohort-specific incidence rate of HZ was 22.2 per 1000 patient-years (95% confidence interval [CI], 18.1-27.4). African Americans (37.6 per 1000 [95% CI, 25.0-56.6]) and heart transplants recipients (40.0 per 1000 [95% CI, 23.2-68.9]) had the highest incidence of HZ. Patients transplanted between 2005 and 2007 had the lowest incidence (15.3 per 1000 [95% CI, 8.2-28.3]). In a multivariable model, African Americans (hazard ratio [HR] 1.88; 95% CI: 1.12, 3.17) and older transplant recipients (HR 1.13; 95% CI: 1.01, 1.27 [per 5-year increment]) had increased relative hazards of HZ.

CONCLUSIONS

These data demonstrate that HZ is a common infectious complication following SOT. Future studies focused on HZ prevention are needed in this high-risk population.

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.

Outcomes of simultaneous pancreas-kidney transplantation in type 2 diabetic recipients

BACKGROUND AND OBJECTIVES

Type 2 diabetic patients with end-stage renal disease may receive a simultaneous pancreas-kidney (SPK) transplant. However, outcomes are not well described. Risks for death and graft failure were examined in SPK type 2 diabetic recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the United Network for Organ Sharing database, outcomes of SPK transplants were compared between type 2 and type 1 diabetic recipients. All primary SPK adult recipients transplanted between 2000 and 2007 (n=6756) were stratified according to end-stage pancreas disease diagnosis (type 1: n=6141, type 2: n=582). Posttransplant complications and risks for death and kidney/pancreas graft failure were compared.

RESULTS

Of the 6756 SPK transplants, 8.6% were performed in recipients with a type 2 diabetes diagnosis. Rates of delayed kidney graft function and primary kidney nonfunction were higher in the type 2 diabetics. Five-year overall and death-censored kidney graft survival were inferior in type 2 diabetics. After adjustment for other risk factors, including recipient (age, race, body weight, dialysis time, and cardiovascular comorbidities), donor, and transplant immune characteristics, type 2 diabetes was not associated with increased risk for death or kidney or pancreas failure when compared with type 1 diabetic recipients.

CONCLUSIONS

After adjustment for other risk factors, SPK recipients with type 2 diabetes diagnosis were not at increased risk for death, kidney failure, or pancreas failure when compared with recipients with type 1 diabetes.

Transition from donor candidates to live kidney donors: the impact of race and undiagnosed medical disease states

BACKGROUND

Living kidney donors (LKD) allow for increased access to lifesaving organs for transplantation. There is a relative paucity of African American (AA) live kidney donors. The prevalence of medical disease in LKD candidates has not been well studied. We examined the medical limitations to living kidney donation in a large Midwestern transplant center.

METHODS

A total of 2519 adults (age ≥ 18) evaluated as potential LKD (PD) between January 1, 1996 and June 30, 2006 were prospectively followed until evaluation outcome (completed live donation, medical exclusion from live donation, non-medical exclusion from live donation). Logistic regression was used to examine the effect of age on donor exclusion, and chi-square tests were used to compare the likelihood of donor exclusions between racial and gender groups.

RESULTS

Sixty percent of PD were female (n = 1300), and 86% were Caucasian (CA) (n = 1862). Overall, 48.7% of PD who underwent evaluation became LKD. The odds of donation were 52% lower in AA compared to CA (OR 0.48 p < 0.001). Among PD excluded from donation, the most common medical diagnoses were hypertension (HTN) (24.7%), inadequate creatinine clearance (10.6%) and a positive final crossmatch (10.5%). The rate of PD exclusion for obesity was twofold higher in AA compared to CA (12.8% vs. 5.8%, p < 0.001).

CONCLUSIONS

Hypertension in PD is equally significant barrier to living kidney donation in AA and CA whereas obesity is a greater barrier in AA.

Vitamin D in solid organ transplantation with special emphasis on kidney transplantation

Within the past decades, vitamin D was identified as having additional physiological functions far beyond calcium homeostasis and bone metabolism. Stimulated by the discovery of the vitamin D receptor in a broad range of tissues as well as the expression of 1α-hydroxylase, the enzyme responsible for the activation of vitamin D, it became evident that the actions of vitamin D are not restricted to cells involved in mineral and bone metabolism. In fact, it affects proliferation, differentiation, and function of a large number of different cell types including cells of the immune system. Vitamin D receptor agonists were found to exert immunosuppressive effects on the adaptive immune system, thus being able to mediate immunologic tolerance. However, they promote the innate immune system and thereby improve the ability of the host to combat invading pathogens. This review summarizes our current understanding of vitamin D as an immunomodulatory agent with special emphasis on its clinical implications in the transplant setting.