Significant racial differences in the key factors associated with early graft loss in kidney transplant recipients

HLA B eplet mismatches in the context of delayed graft function and low tacrolimus trough levels are risk factors influencing the generation of de novo donor-specific antibodies and acute rejection in the early stage after kidney transplantation

BACKGROUND

De novo donor-specific antibody (dnDSA) generation and acute rejection (AR) are the main factors affecting long-term graft survival. This study aims to investigate human leukocyte antigen (HLA) eplet mismatching (MM), delayed graft function (DGF), and tacrolimus (TAC) trough levels on the occurrence of dnDSA and AR in the early stages after kidney transplantation (KT).

METHODS

This retrospective study included 526 cases of deceased donation KT. The effects of DGF, HLA eplet MM, and TAC trough levels on dnDSA and AR occurrence were analyzed with logistic regression analysis.

RESULTS

Multivariate logistic regression analysis showed the independent risk factor of dnDSA generation was HLA B eplet MM (OR: 1.201, 95% CI: 1.007-1.431, P = 0.041). The independent risk factors of AR occurrence include DGF (OR: 4.045, 95% CI: 1.047-15.626, P = 0.043), HLA B eplet MM (OR: 1.090, 95% CI: 1.000-1.187, P = 0.050), and TAC trough levels at 12 months (OR: 0.750, 95% CI: 565-0.997, P = 0.048). HLA B eplet MM combined with DGF and TAC trough levels at 12 months increased the predictive value of dnDSA (AUC 0.735) and AR (AUC 0.730) occurrence. HLA B eplet MM > 9 and TAC trough levels below 5.95 ng/mL at 12 months could increase the risk of early AR occurrence.

CONCLUSIONS

HLA B eplet MM, DGF, and TAC trough levels at 12 months after KT could affect the occurrence of dnDSA and AR in the early stage of KT.

Kidney transplant outcomes in minority populations: can we close the gap?

PURPOSE OF REVIEW

Health disparity in minority populations has been increasingly recognized over the last decade. The COVID-19 pandemic sheds a bright light on this very issue impressing upon the need for more research regarding healthcare in disparate populations. Although kidney transplantation remains the treatment of choice for end-stage renal disease management and longevity of life, access to transplantation remains a critical barrier in minority populations. The literature on disparity in access abounds but remains limited with regards to posttransplantation outcomes. The purpose of this review is to draw attention to existing research and literature in posttransplant outcomes and highlight the overall knowledge gap that persists in postkidney transplant care among disparate populations.

RECENT FINDINGS

The current review focuses on important paradigm shifts in the determinants of outcomes in posttransplantation care in minority populations. It emphasizes a departure from immune mediated causes to more salient health inequities and socioeconomic factors contributing to patient and graft survival which require further investigation.

SUMMARY

Despite increased awareness of health disparity in minority populations, outcomes data postkidney transplantation remains sparse. Critical to the future of kidney transplantation and improved healthcare coordination in minority populations will be a deeper understanding of contributing socio-economic variables in disparate outcomes.

Glycemic management and clinical outcomes in underserved minority kidney transplant recipients with type 2 and posttransplantation diabetes: A single-center retrospective study

AIMS

Little is known about glycemic management, particularly with novel cardio-nephroprotecive agents, in underserved minority kidney transplant recipients with pre-transplant type 2 (T2DM) and posttransplantation diabetes mellitus (PTDM). We assessed glycemic management and outcomes in this high-risk population.

METHODS

We reviewed records of patients who received kidney transplants between June 2012 and December 2014 at a single center. Hemoglobin A1c (HbA1c) and prescribed glucose-lowering medications were examined, and mortality was compared between T2DM, PTDM, and no diabetes (NoDM) patients.

RESULTS

We followed 302 patient records (41.1% Hispanic, 41.1% non-Hispanic black) for a median (IQR) of 45.5 (37.0, 53.0) months post-transplant. Pre-transplant T2DM was present in 152 (50.3%), while 58 (19.2%) developed PTDM and 92 (30.4%) remained NoDM. At 1-year post-transplant, the average HbA1c was 8.1 ± 1.8% in T2DM and 6.6 ± 1.3% in PTDM. No glucose-lowering agents were prescribed in 3.4% of T2DM and 44.8% of PTDM. When treated, both received mostly insulin and metformin. Diabetes, HbA1c and insulin therapy were not independently associated with risk of mortality.

CONCLUSIONS

Glycemic management was suboptimal and relied on older medications. Further studies are needed to assess longer-term outcomes of more rigorous glycemic management, and the value of novel cardio-nephroprotective agents in kidney transplant recipients.

Predicting ideal outcome after pediatric liver transplantation: An exploratory study using machine learning analyses to leverage Studies of Pediatric Liver Transplantation Data

Machine learning analyses allow for the consideration of numerous variables in order to accommodate complex relationships that would not otherwise be apparent in traditional statistical methods to better classify patient risk. The SPLIT registry data were analyzed to determine whether baseline demographic factors and clinical/biochemical factors in the first-year post-transplant could predict ideal outcome at 3 years (IO-3) after LT. Participants who received their first, isolated LT between 2002 and 2006 and had follow-up data 3 years post-LT were included. IO-3 was defined as alive at 3 years, normal ALT (<50) or GGT (<50), normal GFR, no non-liver transplants, no cytopenias, and no PTLD. Heat map analysis and RFA were used to characterize the impact of baseline and 1-year factors on IO-3. 887/1482 SPLIT participants met inclusion criteria; 334 had IO-3. Demographic, biochemical, and clinical variables did not elucidate a visual signal on heat map analysis. RFA identified non-white race (vs white race), increased length of operation, vascular and biliary complications within 30 days, and duct-to-duct biliary anastomosis to be negatively associated with IO-3. UNOS regions 2 and 5 were also identified as important factors. RFA had an accuracy rate of 0.71 (95% CI: 0.68-0.74), PPV = 0.83, and NPV = 0.70. RFA identified participant variables that predicted IO-3. These findings may allow for better risk stratification and personalization of care following pediatric liver transplantation.

Immunologic Risk Assessment and Approach to Immunosuppression Regimen in Kidney Transplantation

The outcomes of kidney transplantation show a steady improvement with an increasing number of transplantations and decreasing incidence of acute rejection episodes. Successful transplantation begins with a comprehensive immunologic risk assessment and judicious choice of therapeutic agents. In this review, we discuss the trends in transplant immunosuppression practices and outcomes in the United States. We discuss practical testing algorithms for clinical decision making in induction therapy and fine-tuning maintenance immunosuppression. We introduce assessment tools for immune monitoring after transplantation and speculate on future directions in management.

A qualitative examination of barriers and solutions to renal transplantation in Malaysia: Key-informants' perspective

INTRODUCTION

End-stage renal disease (ESRD) is increasing globally, and renal transplantation (RT) is the preferred renal replacement therapy to treat ESRD. Internationally, there are only a few countries with RT rates above 50 per million population (pmp), while most of the countries have RT rates between 30-40 pmp. The low- and middle-income countries (LMIC) makes up the majority for the RT rates below 20 pmp in which Malaysia belongs to despite its increasing ESRD rates. There is a need to explore the barriers to access RT with targeted solutions to improve the RT rates and service in LMIC. Thus, a qualitative study was undertaken in Malaysia to address this issue.

METHOD

A qualitative methodological approach was performed between March-May 2018. Semi-structured interviews were used to explore current RT policy and service availability. Key-informants were identified from a detailed stakeholder analysis of RT system in Malaysia. Interviews were digitally audio-recorded, transcribed verbatim, coded with ATLAS.ti software and underwent thematic analysis thoroughly.

RESULTS

Eight key-informants participated in the study. Barriers and related solutions were classified using the socio-ecological model (SEM). As reported, the barriers and solutions of RT in Malaysia are the results of a complex interplay of personal, cultural, and environmental factors. Key barriers are linked to public's attitude and perception towards RT and the unaccommodating practices in the healthcare fraternity for RT. Key-informants provided a systematic solution that shed light on how RT could be improved at each SEM level via effective communication, education and inter-agency collaboration.

CONCLUSION

The SEM provided a framework to foster a better understanding of current practice, barriers, and solutions to RT in Malaysia. This study is the first to explore the barriers and related solutions to RT comprehensively as a whole. Implications of these findings could prompt a policy change for a better RT service delivery model not just for Malaysia but also for other LMIC. Further stakeholder engagement and evaluation of the systems are required to provide insight into best practices that will help to improve the RT rates and service in Malaysia.

Pharmacist-Led, Technology-Assisted Study to Improve Medication Safety, Cardiovascular Risk Factor Control, and Racial Disparities in Kidney Transplant Recipients

Introduction

Health disparities in African-American (AA) kidney transplant recipients compared with non-AA recipients are well established. Cardiovascular disease (CVD) risk control is a significant mediator of this disparity.

Objective

To assess the efficacy of improved medication safety, CVD risk control, and racial disparities in kidney transplant recipients.

Methods

Prospective, pharmacist-led, technology-aided, 6-month interventional clinical trial. A total of 60 kidney recipients with diabetes and hypertension were enrolled. Patients had to be at least one-year post transplant with stable graft function. Primary outcome measured included hypertension, diabetes, and lipid control using intent-to-treat analyses, with differences assessed between AA and non-AA recipients.

Results

The participants mean age was 59 years, with 42% being female and 68% being AA. Overall, patients demonstrated improvements in blood pressure <140/90 mmHg (baseline 50% vs. end of study 68%, p=0.054) and hemoglobin A1c <7% (baseline 33% vs. end of study 47%, p=0.061). AAs demonstrated a significant reduction from baseline in systolic blood pressure (-0.86 mmHg per month, p=0.026), which was not evident in non-AAs (-0.13 mmHg per month, p=0.865). Mean HgbA1c decreased from baseline in the overall group (-0.12% per month, p=0.003), which was similar within AAs (-0.11% per month, p=0.004) and non-AAs (-0.14% per month, p=0.029). There were no changes in low-density lipoproteins, triglycerides, or high-density lipoproteins over the course of the study. Medication errors were significantly reduced and self-reported medication adherence significantly improved over the course of the study.

Conclusion

These results demonstrate the potential efficacy of a pharmacist-led, technology-aided, educational intervention in improving medication safety, diabetes, and hypertension and reducing racial disparities in AA kidney transplant recipients. (ClinicalTrials.gov NCT02763943).

Prolonged-Release vs Immediate-Release Tacrolimus Capsules in Black vs White Kidney Transplant Patients: A Post Hoc Analysis of Phase III Data

BACKGROUND

Black kidney transplant patients experience inferior outcomes compared with other ethnicities. Because scrutiny is required when immunosuppressant drugs are used in such at-risk populations, we report the first large-scale clinical efficacy data assessing prolonged-release tacrolimus (PR-T) in black de novo kidney transplant patients.

METHODS AND MATERIALS

We used logistic regression and proportionate hazards to compare a composite outcome measure (biopsy-proven acute rejection, graft loss, mortality, and loss to follow-up) in black and white patients in treatment groups longer than 24 weeks, from 3 large Phase III randomized controlled trials. Secondary endpoints included tacrolimus trough concentration, dose, and estimated glomerular filtration rate.

RESULTS

The study included 2162 patients whose treatments belonged to two categories (immediate-release tacrolimus: 77 black patients, 721 white patients; and PR-T: 87 black patients, 1277 white patients). Despite demographic factors generally predictive of worse outcomes, efficacy failure among black patients who received PR-T was non-inferior to that among white patients who received either therapy. Compared with immediate-release tacrolimus, black patients who received PR-T achieved stable tacrolimus concentrations 2.5 times faster (21 vs 56 days, P = .04), and more achieved stable target concentrations (76.7% vs 69.3%). Treatment-emergent adverse events were consistent with those reported separately in pivotal trials.

CONCLUSIONS

Overall, black patients who received PR-T achieved non-inferior outcomes compared to white patients, despite higher pretransplant risk among black patients. Moreover, PR-T improved the time to achieve, and the likelihood of reaching, stable therapeutic concentrations among black patients, suggesting that PR-T could improve the consistency of tacrolimus exposure in this patient population.

Xenotransplantation

The transplantation of living cells, tissues or organs from one species to another is termed xenotransplantation. The history of xenotransplantation is as old as allogeneic transplantation itself. Early attempts were made at a time when the immunologic basis of organ rejection were poorly understood. The advent of potent immunosuppressive medications along with the parallel advances in the field of genetic engineering has provided a fresh perspective on the role of xenotransplantation as a means to alleviate the disparity between the number of candidates on the waitlist and the available organs. As the science behind xenotransplantation advances, the transplantation community must take it upon themselves to educate the community at large regarding both the benefits and potential risks of this promising field.

The impact of time-varying clinical surrogates on disparities in African-American kidney transplant recipients - a retrospective longitudinal cohort study

An improved understanding of the impact of clinical surrogates on disparities in African-American (AA) kidney transplantation (KTX) is needed. We conducted a 10-year retrospective longitudinal cohort study of electronically abstracted clinical data assessing the impact of surrogates on disparities in KTX. Clinical surrogates were assessed by posttransplant year (1, 2, 3 or 4) and defined as acute rejection (Banff ≥1A), mean SBP >140 mmHg, tacrolimus variability (CV) >40%, mean glucose >160 mg/dl and mean hemoglobin <10 g/dl. We utilized landmark methodology to minimize immortal time bias and logistic and survival regression to assess outcomes; 1610 KTX were assessed (54.2% AAs), with 1000, 468, 368 and 303 included in the year 1, 2, 3 and 4 complete case analyses, respectively. AAs had significantly higher odds of developing a clinical surrogate, which increased in posttransplant years three and four [OR year 1 1.99 (1.38-2.88), year 2 1.77 (1.20-2.62), year 3 2.35 (1.49-3.71), year 4 2.85 (1.72-4.70)]. Adjusting for the five clinical surrogates in survival models explained a significant portion of the higher risks of graft loss in AAs in post-transplant years three and four. Results suggest focusing efforts on improving late clinical surrogate management within AAs may help mitigate racial disparities in KTX.

Transplant Center Variability in Disparities for African-American Kidney Transplant Recipients

Background

Disparities research has traditionally focused on patient-level variables to ascertain predominant risk factors driving differences in outcomes for African-American (AA) kidney transplant recipients. Our objectives were to determine the magnitude and impact of transplant center variability for graft outcome disparities.

Material/Methods

This was a retrospective cohort study analyzing 25 years of U.S. national transplant registry data at both the patient and center levels using univariate descriptive statistics and multivariable modeling.

Results

A total of 257,024 recipients from 191 centers were analyzed; AAs represented 31.1% of recipients. After adjusting for baseline characteristics, AAs had 42% higher risk of graft loss (aHR 1.42, 95% CI 1.39 to 1.45; p<0.001). Center variability for graft outcome disparities in AAs was significant (race*center interaction term p<0.05), with the aHRs ranging from 0.5 to 4.9; 46% of centers demonstrated a non-statistically significant disparity (aHR p>0.05) and 25% of centers had a large AA disparity (aHR >1.75). In a more recent transplant time period (2000–14), overall racial disparities decreased but center-level disparities increased in variability. Center-level factors significantly associated with increasing disparity included higher acute rejection rates, fewer transplants per year, longer length of stay, lower use of calcineurin inhibitors (CNI), and lower living donor rates.

Conclusions

There is evidence of significant center-level variability in graft outcome disparities for AA kidney recipients. Further, there appears to be a number of center-level factors associated with this variability, including acute rejection rates, CNI use, number of transplants per year, and, in recent years, low living donor rates.

Tacrolimus Trough Concentration Variability and Disparities in African American Kidney Transplantation

BACKGROUND

Low tacrolimus concentrations have been associated with higher risk of acute rejection, particularly within African American (AA) kidney transplant recipients; little is known about intrapatient tacrolimus variabilities impact on racial disparities.

METHODS

Ten year, single-center, longitudinal cohort study of kidney recipients. Intrapatient tacrolimus variability was assessed using the coefficient of variation (CV) measured between 1 month posttransplant and the clinical event, with a comparable period assessed in those without events. Pediatrics, nontacrolimus/mycophenolate regimens, and nonrenal transplants were excluded. Multivariable Cox regression models were used to analyze data.

RESULTS

One thousand four hundred eleven recipients were included (54.4% AA) with 39 521 concentrations used to assess intrapatient tacrolimus CV. Overall, intrapatient tacrolimus CV was higher in AAs versus non-AAs (39.9 ± 19.8 % vs 34.8 ± 15.8% P < 0.001). Tacrolimus variability was a significant risk factor for deleterious clinical outcomes. A 10% increase in tacrolimus CV augmented the risk of acute rejection by 20% (adjusted hazard ratio, 1.20, 1.13-1.28; P < 0.001) and the risk of graft loss by 30% (adjusted hazard ratio, 1.30, 1.23-1.37; P < 0.001), with significant effect modification by race for acute rejection, but not graft loss. High tacrolimus variability (CV >40%) was a significant explanatory variable for disparities in AAs; the crude relative risk of acute rejection in AAs was reduced by 46% when including tacrolimus variability in modeling and reduced by 40% for graft loss.

CONCLUSIONS

These data demonstrate that intrapatient tacrolimus variability is strongly associated with acute rejection in AAs and graft loss in all patients. Tacrolimus variability is a significant explanatory variable for disparities in AA recipients.

Results of ASERTAA, a Randomized Prospective Crossover Pharmacogenetic Study of Immediate-Release Versus Extended-Release Tacrolimus in African American Kidney Transplant Recipients

BACKGROUND

Differences in tacrolimus dosing across ancestries is partly attributable to polymorphisms in CYP3A5 genes that encode tacrolimus-metabolizing cytochrome P450 3A5 enzymes. The CYP3A5*1 allele, preponderant in African Americans, is associated with rapid metabolism, subtherapeutic concentrations, and higher dose requirements for tacrolimus, all contributing to worse outcomes. Little is known about the relationship between CYP3A5 genotype and the tacrolimus pharmacokinetic area under the curve (AUC) profile in African Americans or whether pharmacogenetic differences exist between conventional twice-daily, rapidly absorbed, immediate-release tacrolimus (IR-Tac) and once-daily extended-release tacrolimus (LifeCycle Pharma Tac [LCPT]) with a delayed absorption profile.

STUDY DESIGN

Randomized prospective crossover study.

SETTING & PARTICIPANTS

50 African American maintenance kidney recipients on stable IR-Tac dosing.

INTERVENTION

Recipients were randomly assigned to continue IR-Tac on days 1 to 7 and then switch to LCPT on day 8 or receive LCPT on days 1 to 7 and then switch to IR-Tac on day 8. The LCPT dose was 85% of the IR-Tac total daily dose.

OUTCOMES

Tacrolimus 24-hour AUC (AUC_0-24), peak and trough concentrations (C_max and C_min), time to peak concentration, and bioavailability of LCPT versus IR-Tac, according to CYP3A5 genotype.

MEASUREMENTS

CYP3A5 genotype, 24-hour tacrolimus pharmacokinetic profiles.

RESULTS

∼80% of participants carried the CYP3A5*1 allele (CYP3A5 expressers). There were no significant differences in AUC_0-24 or C_min between CYP3A5 expressers and nonexpressers during administration of either IR-Tac or LCPT. With IR-Tac, tacrolimus C_max was 33% higher in CYP3A5 expressers compared with nonexpressers (P=0.04): With LCPT, this difference was 11% (P=0.4).

LIMITATIONS

This was primarily a pharmacogenetic study rather than an efficacy study; the follow-up period was too short to capture clinical outcomes.

CONCLUSIONS

Achieving therapeutic tacrolimus trough concentrations with IR-Tac in most African Americans results in significantly higher peak concentrations, potentially magnifying the risk for toxicity and adverse outcomes. This pharmacogenetic effect is attenuated by delayed tacrolimus absorption with LCPT.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov, with study number NCT01962922.

Cytolytic Induction Therapy Improves Clinical Outcomes in African-American Kidney Transplant Recipients

OBJECTIVE

Determine the impact of cytolytic versus IL-2 receptor antibody (IL-2RA) induction on acute rejection, graft loss and death in African-American (AA) kidney transplant (KTX) recipients.

BACKGROUND

AAs are underrepresented in clinical trials in transplantation; thus, there is controversy regarding the optimal choice of perioperative antibody induction in KTX to improve outcomes.

METHODS

National cohort study using US transplant registry data from January 1, 2000 to December 31, 2009 in adult solitary AA KTX recipients, with at least 5 years of follow-up. Multivariable logistic and Cox regression were utilized to assess the outcomes of acute rejection, graft loss, and mortality, with interaction terms to assess effect modification.

RESULTS

Twenty-five thousand eighty-four adult AAs receiving solitary KTX were included, 16,927 (67.5%) received cytolytic induction and 8157 (32.5%) received IL-2RA induction. After adjustment for recipient sociodemographics, donor, and transplant characteristics, the use of cytolytic induction therapy reduced the risk of acute rejection by 32% (OR 0.68, 0.62-0.75), graft loss by 9% (HR 0.91, 0.86-0.97), and death by 12% (HR 0.88, 0.83-0.94). There were a number of significant effect modifiers, including public insurance, panel reactive antibody, delayed graft function, and steroid withdrawal; in these groups, cytolytic induction substantially improved clinical outcomes.

CONCLUSIONS

These data demonstrate that cytolytic induction therapy, as compared with IL-2RA, reduces the risk of rejection, graft loss, and death in adult AA KTX recipients, particularly in those who are sensitized, receive public insurance, develop delayed graft function, or undergo steroid withdrawal.

Quantifying the Race Stratified Impact of Socioeconomics on Graft Outcomes in Kidney Transplant Recipients

BACKGROUND

Socioeconomic status (SES) is a significant determinant of health outcomes and may be an important component of the causal chain surrounding racial disparities in kidney transplantation. The social adaptability index (SAI) is a validated and quantifiable measure of SES, with a lack of studies analyzing this measure longitudinally or between races.

METHODS

Longitudinal cohort study in adult kidney transplantation transplanted at a single-center between 2005 and 2012. The SAI score includes 5 domains (employment, education, marital status, substance abuse and income), each with a minimum of 0 and maximum of 3 for an aggregate of 0 to 15 (higher score → better SES).

RESULTS

One thousand one hundred seventy-one patients were included; 624 (53%) were African American (AA) and 547 were non-AA. African Americans had significantly lower mean baseline SAI scores (AAs 6.5 vs non-AAs 7.8; P < 0.001). Cox regression analysis demonstrated that there was no association between baseline SAI and acute rejection in non-AAs (hazard ratio [HR], 0.92; 95% confidence interval [95% CI], 0.81-1.05), whereas it was a significant predictor of acute rejection in AAs (HR, 0.89; 95% CI, 0.80-0.99). Similarly, a 2-stage approach to joint modelling of time to graft loss and longitudinal SAI did not predict graft loss in non-AAs (HR, 1.01; 95% CI, 0.28-3.62), whereas it was a significant predictor of graft loss in AAs (HR, 0.23; 95% CI, 0.06-0.93).

CONCLUSIONS

After controlling for confounders, SAI scores were associated with a lower risk of acute rejection and graft loss in AA kidney transplant recipients, whereas neither baseline nor follow-up SAI predicted outcomes in non-AA kidney transplant recipients.

Overall Graft Loss Versus Death-Censored Graft Loss: Unmasking the Magnitude of Racial Disparities in Outcomes Among US Kidney Transplant Recipients

BACKGROUND

Black kidney transplant recipients experience disproportionately high rates of graft loss. This disparity has persisted for 40 years, and improvements may be impeded based on the current public reporting of overall graft loss by US regulatory organizations for transplantation.

METHODS

Longitudinal cohort study of kidney transplant recipients using a data set created by linking Veterans Affairs and US Renal Data System information, including 4918 veterans transplanted between January 2001 and December 2007, with follow-up through December 2010. Multivariable analysis was conducted using 2-stage joint modeling of random and fixed effects of longitudinal data (linear mixed model) with time to event outcomes (Cox regression).

RESULTS

Three thousand three hundred six non-Hispanic whites (67%) were compared with 1612 non-Hispanic black (33%) recipients with 6.0 ± 2.2 years of follow-up. In the unadjusted analysis, black recipients were significantly more likely to have overall graft loss (hazard ratio [HR], 1.19; 95% confidence interval [95% CI], 1.07-1.33), death-censored graft loss (HR, 1.67; 95% CI, 1.45-1.92), and lower mortality (HR, 0.83; 95% CI, 0.72-0.96). In fully adjusted models, only death-censored graft loss remained significant (HR, 1.38; 95% CI, 1.12-1.71; overall graft loss [HR, 1.08; 95% CI, 0.91-1.28]; mortality [HR, 0.84; 95% CI, 0.67-1.06]). A composite definition of graft loss reduced the magnitude of disparities in blacks by 22%.

CONCLUSIONS

Non-Hispanic black kidney transplant recipients experience a substantial disparity in graft loss, but not mortality. This study of US data provides evidence to suggest that researchers should focus on using death-censored graft loss as the primary outcome of interest to facilitate a better understanding of racial disparities in kidney transplantation.

A Comparative Effectiveness Analysis of Early Steroid Withdrawal in Black Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES

There is continued debate whether early steroid withdrawal is safe to use in high-immunologic risk patients, such as blacks. The goal of this study was to use comparative effectiveness methodology to elucidate the safety of early steroid withdrawal in blacks with kidney transplants.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our cohort study used United Network of Organ Sharing data including all adult black kidney transplant recipients from 2000 to 2009 followed through 2014. Propensity score matching was used to equalize baseline risk between continued steroid and early steroid withdrawal groups. Interaction terms were used to assess if the effect of early steroid withdrawal on outcomes varied by baseline and post-transplant factors. Of 26,582 eligible black patients with kidney transplants (5825 [21.9%] with early steroid withdrawal), 5565 patients with early steroid withdrawal were matched to 5565 blacks on continued steroid use.

RESULTS

Black patients with early steroid withdrawal had similar risk of graft loss (hazard ratio, 0.98; 95% confidence interval, 0.92 to 1.04; P=0.42) and lower risk of death (hazard ratio, 0.91; 95% confidence interval, 0.84 to 0.99; P=0.02), primarily driven by a late mortality advantage (>4 years post-transplant). Delayed graft function, cytolytic induction, tacrolimus, and mycophenolate significantly modified the effect of early steroid withdrawal on outcomes (P<0.05). Acute rejection rates were slightly higher in the continued steroid group (13.0% versus 11.3%, respectively; P<0.01), but this was not associated with graft or patient survival.

CONCLUSIONS

Overall, early steroid withdrawal in black kidney transplant recipients was not associated with graft loss but seemed to be associated with better long-term patient survival. Early steroid withdrawal in blacks not receiving cytolytic induction, tacrolimus, and mycophenolate or those with delayed graft function was associated with higher risk of graft loss and death.

Outcome disparities between African Americans and Caucasians in contemporary kidney transplant recipients

BACKGROUND

Racial disparities in African-American (AA) kidney transplant have persisted for nearly 40 years, with limited data available on the scope of this issue in the contemporary era of transplantation.

METHODS

Descriptive retrospective cohort study of US registry data including adult solitary kidney transplants between Jan 1, 2005 to Dec 31, 2009.

RESULTS

60,695 recipients were included; 41,426 Caucasians (68%) and 19,269 AAs (32%). At baseline, AAs were younger, had lower college graduation rates, were more likely to be receiving public health insurance and have diabetes. At one-year post-transplant, AAs had 62% higher risk of graft loss (RR 1.62, 95% CI 1.50-1.75) which increased to 93% at five years (RR 1.93, 95% CI 1.85-2.01). Adjusted risk of graft loss, accounting for baseline characteristics, was 60% higher in AAs (HR 1.61 [1.52-1.69]). AAs had significantly higher risk of acute rejection and delayed graft function.

CONCLUSION

AAs continue to experience disproportionately high rates of graft loss within the contemporary era of transplant, which are related to a convergence of an array of socioeconomic and biologic risk factors.

Impact of Cardiovascular Risk Factors on Graft Outcome Disparities in Black Kidney Transplant Recipients

Although outcome inequalities for non-Hispanic black (NHB) kidney transplant recipients are well documented, there is paucity in data assessing the impact of cardiovascular disease (CVD) risk factors on this disparity in kidney transplantation. This was a longitudinal study of a national cohort of veteran kidney recipients transplanted between January 2001 and December 2007. Data included baseline characteristics acquired through the United States Renal Data System linked to detailed clinical follow-up information acquired through the Veterans Affairs electronic health records. Analyses were conducted using sequential multivariable modeling (Cox regression), incorporating blocks of variables into iterative nested models; 3139 patients were included (2095 non-Hispanic whites [66.7%] and 1044 NHBs [33.3%]). NHBs had a higher prevalence of hypertension (100% versus 99%; P<0.01) and post-transplant diabetes mellitus (59% versus 53%; P<0.01) with reduced control of hypertension (blood pressure <140/90 60% versus 69%; P<0.01), diabetes mellitus (A1c <7%, 35% versus 47%; P<0.01), and low-density lipoprotein (<100 mg/dL, 55% versus 61%; P<0.01). Adherence to medications used to manage CVD risk was significantly lower in NHBs. In the fully adjusted models, the independent risk of graft loss in NHBs was substantially reduced (unadjusted hazard ratio, 2.00 versus adjusted hazard ratio, 1.49). CVD risk factors and control reduced the influence of NHB race by 9% to 18%. Similar trends were noted for mortality, and estimates were robust across in sensitivity analyses. These results demonstrate that NHB kidney transplant recipients have significantly higher rates of CVD risk factors and reduced CVD risk control. These issues are likely partly related to medication nonadherence and meaningfully contribute to racial disparities for graft outcomes.

Genomics in CKD: Is This the Path Forward?

Recent advances in genomics and sequencing technology have led to a better understanding of genetic risk in CKD. Genetics could account in part for racial differences in treatment response for medications including antihypertensives and immunosuppressive medications due to its correlation with ancestry. However, there is still a substantial lag between generation of this knowledge and its adoption in routine clinical care. This review summarizes the recent advances in genomics and CKD, discusses potential reasons for its underutilization, and highlights potential avenues for application of genomic information to improve clinical care and outcomes in this particularly vulnerable population.