Does race-matched liver transplantation offer any graft survival benefit?

Recipient Age Predicts 20-Year Survival in Pediatric Liver Transplant

INTRODUCTION

Pediatric liver transplant recipients have demonstrated excellent long-term survival. The purpose of this analysis is to investigate factors associated with 20-year survival to identify areas for improvement in patient care.

METHODS

Kaplan-Meier with log-rank test as well as univariate and multivariate logistic regression methods were used to retrospectively analyze 4,312 liver transplant recipients under the age of 18 between September 30, 1987 and March 9, 1998. Our primary endpoint was 20-year survival among one-year survival.

RESULTS

Logistic regression analysis identified recipient age as a significant risk factor, with recipients below 5 years old having a higher 20-year survival rate (p < 0.001). A preoperative primary diagnosis of a metabolic dysfunction was found to be protective compared to other diagnoses (OR 1.64, CI 1.20-2.25). African-American ethnicity (OR 0.71, CI 0.58-0.87) was also found to be a risk factor for mortality. Technical variant allografts (neither living donor nor cadaveric) were not associated with increased or decreased rates of 20-year survival.

CONCLUSIONS

Our analysis suggests that long-term survival is inversely correlated with recipient age following pediatric liver transplant. If validated with further studies, this conclusion may have profound implications on the timing of pediatric liver transplantation.

Joint testing of donor and recipient genetic matching scores and recipient genotype has robust power for finding genes associated with transplant outcomes

Genetic matching between transplant donor and recipient pairs has traditionally focused on the human leukocyte antigen (HLA) regions of the genome, but recent studies suggest that matching for non-HLA regions may be important as well. We assess four genetic matching scores for use in association analyses of transplant outcomes. These scores describe genetic ancestry distance using identity-by-state, or genetic incompatibility or mismatch of the two genomes and therefore may reflect different underlying biological mechanisms for donor and recipient genes to influence transplant outcomes. Our simulation studies show that jointly testing these scores with the recipient genotype is a powerful method for preliminary screening and discovery of transplant outcome related single nucleotide polymorphisms (SNPs) and gene regions. Following these joint tests with marginal testing of the recipient genotype and matching score separately can lead to further understanding of the biological mechanisms behind transplant outcomes. In addition, we present results of a liver transplant data analysis that shows joint testing can detect SNPs significantly associated with acute rejection in liver transplant.

Disparities in liver transplantation: the association between donor quality and recipient race/ethnicity and sex

BACKGROUND

We aimed to examine the association between recipient race/ethnicity and sex, donor liver quality, and liver transplant graft survival.

METHODS

Adult non-status 1 liver recipients transplanted between March 1, 2002, and December 31, 2008, were identified using Scientific Registry of Transplant Recipients data. The factors of interest were recipient race/ethnicity and sex. Donor risk index (DRI) was used as a donor quality measure. Logistic regression was used to assess the association between race/ethnicity and sex in relation to the transplantation of low-quality (high DRI) or high-quality (low DRI) livers. Cox regression was used to assess the association between race/ethnicity and sex and liver graft failure risk, accounting for DRI.

RESULTS

Hispanics were 21% more likely to receive low-quality grafts compared to whites (odds ratio [OR]=1.21, P=0.002). Women had greater odds of receiving a low-quality graft compared to men (OR=1.24, P<0.0001). Despite adjustment for donor quality, African American recipients still had higher graft failure rates compared to whites (hazard ratio [HR]=1.28, P<0.001). Hispanics (HR=0.89, P=0.023) had significantly lower graft failure rates compared to whites despite higher odds of receiving a higher DRI graft. Using an interaction model of DRI and race/ethnicity, we found that the impact of DRI on graft failure rates was significantly reduced for African Americans compared to whites (P=0.02).

CONCLUSIONS

This study shows that while liver graft quality differed significantly by recipient race/ethnicity and sex, donor selection practices do not seem to be the dominant factor responsible for worse liver transplant outcomes for minority recipients.

Viral status at the time of liver transplantation for hepatocellular carcinoma: a modern predictor of longterm survival

OBJECTIVES

The impact of pre-transplant hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection in patients with hepatocellular carcinoma (HCC) is not well described. This study was conducted to test the hypothesis that viral status is an independent predictor of retransplantation rates, graft survival (GS) and overall survival (OS) in patients undergoing liver transplantation for HCC.

METHODS

Patients with HCC were identified from the Organ Procurement and Transplantation Network database (2005-2012), and categorized by viral status according to these categories: HBV-/HCV-; HBV+/HCV-; HBV-/HCV+, and HBV+/HCV+.

RESULTS

Of 7742 patients transplanted for HCC, 7060 had known HBV and HCV status. Five-year GS and OS were highest in recipients who were HBV+/HCV-, at 75% and 78%, respectively, compared with patients who were HBV-/HCV- (GS = 63%, OS = 66%), HBV-/HCV+ (GS = 64%, OS = 60%) or HBV+/HCV+ (GS = 60%, OS = 62%). In multivariable analyses, HBV-/HCV+ patients were more likely than HBV+/HCV- patients to undergo repeat transplantation. Patients who were HBV-/HCV+ also had poorer GS and OS than both HBV-/HCV- and HBV+/HCV- patients. Other independent predictors of poorer OS included older age, higher Model for End-stage Liver Disease score, African-American race, and diabetes. The few HBV+/HCV+ patients (n = 138) showed trends toward fewer retransplantations, prolonged GS and prolonged OS compared with HBV-/HCV+ patients. In adjusted models, antiviral medications did not impact GS or OS.

CONCLUSIONS

In the era of modern selection criteria, viral status is an independent predictor of outcome following liver transplantation for HCC. Both HBV-/HCV- and HBV+/HCV- patients have superior GS and OS compared with HBV-/HCV+ patients.

Outcome of liver transplantation for recipients with hepatitis B and hepatitis C virus coinfection: analysis of the UNOS data

BACKGROUND

Coinfection by Hepatitis B virus (HBV) and hepatitis C virus (HCV) has been reported to increase risk of graft failure for liver transplant recipients. But other studies have controverted that finding. The aim of this study was to determine whether-after adjustments for other important predictors-HBV/HCV coinfection was associated with worse liver graft survival than HBV or HCV mono-infection.

METHODS

A retrospective cohort study examined Organ Procurement and Transplantation Network/United Network Organ Sharing data for 48,654 deceased-donor primary liver-only transplants that were performed on adults between January 1, 1995, and August 31, 2009, and that included recipient and donor HBV/HCV status. Recipients were classified into four groups: the HBV/HCV coinfected [B+/C+]; HBV mono-infected [B+/C-]; HCV mono-infected [B-/C+]; and hepatitis uninfected [B-/C-]. Kaplan-Meier methods were used to calculate liver graft survival rates, Cox proportional hazard models were used to estimate the effect of hepatitis virus infection, and adjusted for potential confounders.

RESULTS

Graft survival rates were highest with B+/C-: 85.3% 1-year survival and 63.0% 10-year survival. Graft survival with B+/C+ was superior to survival with B-/C+: 83.5% 1-year survival and 53.6% 10-year survival vs. B-/C+: 82.9% 1-year survival and 46.1% 10-year survival. Survival with B-/C-: 83.6% 1-year survival and 56.6% 10-year survival was superior to survival with B+/C+ (shown above). After adjustment for confounders, and with the coinfected as reference, B-/C+ recipients had a higher risk of graft loss (hazard ratio, 1.35; 95% CI, 1.10-1.66); the other two groups had a lower risk.

CONCLUSIONS

Our results suggested-despite reports to the contrary-statistically better graft outcomes with HBV/HCV coinfection than with HCV mono-infection.

The effect of donor race on the survival of Black Americans undergoing liver transplantation for chronic hepatitis C

The purpose of this study was to determine the effect of donor race on the outcome of black patients with chronic hepatitis C infection who undergo liver transplantation. The records for deceased donor liver transplants that occurred in the United States between January 1998 and December 2007 were obtained from the United Network for Organ Sharing. 26,212 records contained sufficient data to be included in the analysis. Of these, 11,989 (45.7%) records were for patients positive for hepatitis C virus (HCV) and 1292 (4.9%) were for patients both HCV-positive and black. Black recipients with white donors were found to have significantly worse outcomes than all other recipient-donor race combinations (P < 0.001). The crude 5-year survival rate for black recipients who had a black donor was 14% higher than the 5-year survival rate for black recipients who had a white donor. Multivariate regression analysis determined that a graft from a race-unmatched donor was an independent risk factor for graft failure (hazard ratio = 1.41, 95% confidence interval = 1.11-1.79) among HCV-positive black recipients but not among HCV-negative black recipients after adjustments for donor age, recipient age, cold ischemia time, serum creatinine, serum bilirubin, diabetes mellitus, body mass index, and donor cytomegalovirus status. The observation that race-unmatched grafts are a risk factor in HCV-positive black recipients, but not in HCV-negative black recipients, suggests an alteration of the graft-host relationship by HCV. In conclusion, our results suggest that HCV-positive black recipients who undergo liver transplantation can have increased graft survival if their donors are black, with survival rates approaching those of white liver transplant recipients.

Liver transplantation in children with metabolic disorders in the United States

We studied pediatric liver transplantation for metabolic disease in a large national cohort to determine whether smaller studies suggesting a survival advantage for these recipients could be corroborated. We also hoped to determine whether higher survival rates in recipients with metabolic disease are associated with lack of structural liver disease, and to evaluate these recipients' risk factors for mortality. Data from the Scientific Registry of Transplant Recipients were used to analyze nationwide results (1990-99) of pediatric liver transplantation for patients with biliary atresia and metabolic disease. Adjusted patient survival rates for children with metabolic disease at 1 and 5 years were 94% and 92%, respectively, - significantly higher than for recipients with biliary atresia (90% and 86%) (p = 0.008). Cox regression models identified recipient black race [relative risk (RR) = 5.1] and simultaneous transplantation of other organs (RR = 3.2) as significant risk factors for mortality in the metabolic group. Adjusted survival rates for metabolic patients with structural and nonstructural liver diseases were similar to each other at both 1 and 5 years. Children with metabolic disease had significantly higher adjusted short- and long-term post-transplant survival rates than those with biliary atresia. Structural disease was not a risk factor for worse outcomes.

Role of gender and race mismatch and graft failure in patients undergoing liver transplantation

Previous data have suggested an increased risk of graft failure in male recipients of female livers, and in nonwhite recipients of orthotopic liver transplantation. United Network for Organ Sharing records of liver transplantations from 1992 through 2000 with at least one follow-up visit were reviewed. Analysis of these data was performed with proportional hazards regression, controlling for follow-up time, age, gender, ethnicity, number of comorbidities, functional status at time of transplant, and status 1 designation. Separate analyses comparing transplants among whites and blacks only and matched versus mismatched transplants for male and female recipients were performed. The results revealed that gender-mismatched patients (n = 13,992) had a higher likelihood of graft failure when compared with gender matched transplants (n = 18,522) (12.2% versus 11.3% respectively, P =.013). After controlling for the above potential confounders, gender-mismatched patients were found to have a 6.9% increase in likelihood of graft failure, (P =.042). Female recipients receiving male organs had no significant change in the risk of graft failure (11.5%; P =.368). A worse outcome was found in male recipients receiving female organs (12.9%; P =.0003). Graft failure rate among patients with donors matched by race (white to white or nonwhite to nonwhite; n = 21,818) was 11.6% versus 11.9%, and among unmatched patients (n = 10,697), the difference was not significant (P =.33). Multivariate regression analysis controlling for potential confounders confirmed that this difference was not significant (P =.21). Mismatch between black donors and white recipients was found to increase the risk of liver graft failure (27.4%, P = <.0001), independently of gender, number of comorbidities, and functional status at time of transplant.