Donor Risk Index for African American liver transplant recipients with hepatitis C virus

The Impact of Health Care Algorithms on Racial and Ethnic Disparities : A Systematic Review

BACKGROUND

There is increasing concern for the potential impact of health care algorithms on racial and ethnic disparities.

PURPOSE

To examine the evidence on how health care algorithms and associated mitigation strategies affect racial and ethnic disparities.

DATA SOURCES

Several databases were searched for relevant studies published from 1 January 2011 to 30 September 2023.

STUDY SELECTION

Using predefined criteria and dual review, studies were screened and selected to determine: 1) the effect of algorithms on racial and ethnic disparities in health and health care outcomes and 2) the effect of strategies or approaches to mitigate racial and ethnic bias in the development, validation, dissemination, and implementation of algorithms.

DATA EXTRACTION

Outcomes of interest (that is, access to health care, quality of care, and health outcomes) were extracted with risk-of-bias assessment using the ROBINS-I (Risk Of Bias In Non-randomised Studies - of Interventions) tool and adapted CARE-CPM (Critical Appraisal for Racial and Ethnic Equity in Clinical Prediction Models) equity extension.

DATA SYNTHESIS

Sixty-three studies (51 modeling, 4 retrospective, 2 prospective, 5 prepost studies, and 1 randomized controlled trial) were included. Heterogenous evidence on algorithms was found to: a) reduce disparities (for example, the revised kidney allocation system), b) perpetuate or exacerbate disparities (for example, severity-of-illness scores applied to critical care resource allocation), and/or c) have no statistically significant effect on select outcomes (for example, the HEART Pathway [history, electrocardiogram, age, risk factors, and troponin]). To mitigate disparities, 7 strategies were identified: removing an input variable, replacing a variable, adding race, adding a non-race-based variable, changing the racial and ethnic composition of the population used in model development, creating separate thresholds for subpopulations, and modifying algorithmic analytic techniques.

LIMITATION

Results are mostly based on modeling studies and may be highly context-specific.

CONCLUSION

Algorithms can mitigate, perpetuate, and exacerbate racial and ethnic disparities, regardless of the explicit use of race and ethnicity, but evidence is heterogeneous. Intentionality and implementation of the algorithm can impact the effect on disparities, and there may be tradeoffs in outcomes.

PRIMARY FUNDING SOURCE

Agency for Healthcare Quality and Research.

The donor risk index: A decade of experience

In 2006, derivation of the donor risk index (DRI) highlighted the importance of donor factors for successful liver transplantation. Over the last decade, the DRI has served as a useful metric of donor quality and has enhanced our understanding of donor factors and their impact upon recipients with hepatitis C virus, those with low Model for End-Stage Liver Disease (MELD) score, and individuals undergoing retransplantation. DRI has provided the transplant community with a common language for describing donor organ characteristics and has served as the foundation for several tools for organ risk assessment. It is a useful tool in assessing the interactions of donor factors with recipient factors and their impact on posttransplant outcomes. However, limitations of statistical modeling, choice of donor factors, exclusion of unaccounted donor and geographic factors, and the changing face of the liver transplant recipient have tempered its widespread use. In addition, the DRI was derived from data before the MELD era but is currently being applied to expand the donor pool while concurrently meeting the demands of a dynamic allocation system. A decade after its introduction, DRI remains relevant but may benefit from being updated to provide guidance in the use of extended criteria donors by accounting for the impact of geography and unmeasured donor characteristics. DRI could be better adapted for recipients with nonalcoholic fatty liver disease by examining and including recipient factors unique to this population. Liver Transplantation 23 1216-1225 2017 AASLD.

Impact of Donor Recipient Gender and Race Mismatch on Graft Outcomes in Patients With End-Stage Liver Disease Undergoing Liver Transplantation

CONTEXT

The discrepancy between donor supply and organ demand increased the possibility of gender and race mismatch between the donors and recipients. However, the findings of their impact on graft and patient survival are outdated and mixed.

OBJECTIVE

To estimate the effects of gender and race mismatch on graft survival and patient survival among adult patients (18 years and older) with end-stage liver disease.

DESIGN

A total of 38 768 patients undergoing liver transplant between 2002 and 2011 were identified from United Network for Organ Sharing database. Kaplan-Meier curves, log-rank tests, and Cox proportional hazard regressions with backward elimination adopting a marginal approach with a working independence assumption and stratification on recipient hepatitis C virus status were used.

MAIN OUTCOME MEASURES

Posttransplantation graft survival and patient survival.

RESULTS

Both gender mismatch (hazard ratio [HR]: 1.14, 95% confidence interval [CI]: 1.09-1.12) and race mismatch (HR 1.08, 95%C: 1.04-1.12) had significantly adverse effects on graft survival and patient survival after controlling for other factors, especially among hepatitis C-positive female recipients with male donors (HR 1.13, 95%CI 1.03-1.24), black recipients with white donors (1.39, 1.29-1.49) or Hispanic donors (HR 1.48, 95%CI 1.27-1.72), and these effects were even worse among hepatitis C-positive recipients.

CONCLUSION

Gender and race mismatch between donors and recipients adversely affected graft survival and patient survival among adult patients with end-stage liver disease, both independently and after the adjustment for other factors. Future research is recommended to explore other factors such as new model for end-stage liver disease sharing policy change and disparities in access to waiting-list or transplantation.

Key donor factors associated with graft loss among liver transplant recipients with human immunodeficiency virus

BACKGROUND

Human immunodeficiency virus (HIV)-infected liver transplant (LT) recipients have higher risk of graft loss than HIV-uninfected recipients. As the original donor risk index excluded HIV-positive patients, donor factors associated with graft loss in HIV-positive recipients are unknown.

METHODS

Identifying all HIV-positive patients in the Scientific Registry of Transplant Recipients, supplemented by all HIV-infected patients in the solid organ transplantation in HIV: Multi-Site Study (HIV-TR), we evaluated donor factors associated with graft loss among HIV-positive recipients transplanted between March 2002 and August 2012.

RESULTS

A total of 249 HIV-positive LT recipients were followed for median 2.4 (interquartile range [IQR]: 0.8-4.9) years. In univariate analysis, donor diabetes (HR=2.09; P=.002) and donor hypertension (HR=1.43; P=.048) were significantly associated with graft loss, and African-American (AA) recipient:non-AA donor race mismatch (HR=1.60; P=.07), other cause of donor death compared to trauma (HR=2.02; P=.09), and donor age 30 years or older (HR=1.53; P=.05) were of borderline significance. In multivariate analysis, donor diabetes (HR=2.12; 95% CI: 1.33-3.38; P=.002) was the only significant predictor of graft loss.

CONCLUSION

In HIV-positive LT recipients, risk of graft loss is strongly influenced by donor diabetes. This information may be useful to transplant physicians seeking to optimize overall graft survival in their HIV-positive LT recipients.

Donor Factors Including Donor Risk Index Predict Fibrosis Progression, Allograft Loss, and Patient Survival following Liver Transplantation for Hepatitis C Virus

BACKGROUND

The utilization of liver transplantation (LT) is limited by the availability of suitable organs. This study aimed to assess the impact of the donor risk index (DRI) and other donor characteristics on fibrosis progression, graft, and patient survival in hepatitis C virus (HCV)-infected LT recipients.

METHODS

HCV-infected LT recipients who had at least 2 post-LT protocol liver biopsy specimens available were included. Hazard ratio for bivariate analysis was computed using Cox proportional hazard regression analysis.

RESULTS

Of 312 recipients, 26.6% died over a median follow-up of 58.5 months (95% CI: 46.5-67.3). Fourteen patients underwent re-transplantation. Mean time to graft failure was 84.3 months, median follow-up: 59 months, 95% CI (48.2, 68.3). DRI >1.5 was significantly associated with patient and graft survival (P = 0.04). Of the subset of 104 individuals who underwent histological analysis, 67.3% progressed to ≥F2. On multivariate analysis, significant donor-specific predictors of fibrosis progression were: donor age >50 years and DRI >1.7.

CONCLUSIONS

(1) Fibrosis progression in HCV-infected LT recipients is strongly associated with donor characteristics, specifically donor age and DRI. (2) DRI, an objective measure of donor quality, appears to correlate both with rate of histological progression and overall patient/graft survival.

The corrected donor age for hepatitis C virus-infected liver transplant recipients

Donor age has become the dominant donor factor used to predict graft failure (GF) after liver transplantation (LT) in hepatitis C virus (HCV) recipients. The purpose of this study was to develop and validate a model of corrected donor age (CDA) for HCV LT recipients that transforms the risk of other donor factors into the scale of donor age. We analyzed all first LT recipients with HCV in the United Network for Organ Sharing (UNOS) registry from January 1998 to December 2007 (development cohort, n = 14,538) and January 2008 to December 2011 (validation cohort, n = 7502) using Cox regression, excluding early GF (<90 days from LT). Accuracy in predicting 1 year GF (death or repeat LT) was assessed with the net reclassification index (NRI). In the development cohort, after controlling for pre-LT recipient factors and geotemporal trends (UNOS region, LT year), the following donor factors were independent predictors of GF, all P < 0.05: donor age (hazard ratio [HR], 1.02/year), donation after cardiac death (DCD; HR, 1.31), diabetes (HR, 1.23), height < 160 cm (HR, 1.13), aspartate aminotransferase (AST) ≥ 120 U/L (HR, 1.10), female (HR, 0.94), cold ischemia time (CIT; HR, 1.02/hour), and non-African American (non-AA) donor-African American (AA) recipient (HR, 1.65). Transforming these risk factors into the donor age scale yielded the following: DCD = +16 years; diabetes = +12 years; height < 160 cm = +7 years; AST ≥ 120 U/L = +5 years; female = -4 years; and CIT = +1 year/hour > 8 hours and -1 year/hour < 8 hours. There was a large effect of donor-recipient race combinations: +29 years for non-AA donor and an AA recipient but only +5 years for an AA donor and an AA recipient, and -2 years for an AA donor and a non-AA recipient. In a validation cohort, CDA better classified risk of 1-year GF versus actual age (NRI, 4.9%; P = 0.009) and versus the donor risk index (9.0%, P < 0.001). The CDA, compared to actual donor age, provides an intuitive and superior estimation of graft quality for HCV-positive LT recipients because it incorporates additional factors that impact LT GF rates.

Association between donor and recipient smoothened gene polymorphisms and the risk of hepatocellular carcinoma recurrence following orthotopic liver transplantation in a Han Chinese population

Hepatocellular carcinoma (HCC) recurrence after orthotopic liver transplantation (OLT) is potential cause for the poor outcome. Smoothened (SMO) gene has been considered associating with HCC and HCC recurrence, but its association with HCC recurrence after OLT is not clear yet. In this study, we aim at evaluating the association between donor and recipient SMO gene polymorphisms and HCC recurrence after OLT. A total of 76 patients with HCC who had undergone OLT from July 2007 to August 2012 were included. A single nucleotide polymorphism (SNP), SMO rs3824, located at the 3'UTR region, was genotyped and analyzed in both donor and recipient. We demonstrated that recipient rs3824 polymorphism was significantly associated with HCC recurrence following OLT. In multivariate logistic regression analysis, TNM stage (p = 0.001), recipient SMO rs3824 genotype (CG vs. CC/GG p = 0.001), and histologic grade (p = 0.019) were identified as independent risk factors of HCC recurrence. Recurrence-free survival (RFS) and overall survival (OS) were significantly higher in the recipient CC/GG group than in the CG group (p = 0.003 and p = 0.011, respectively). Cox proportional hazards modeling revealed that TNM stage, recipient SMO rs3824 genotype, pre-OLT serum AFP level, and histologic grade were independent factors (p < 0.05) for patients' clinical outcomes. In conclusion, recipient SMO rs3824 polymorphism is associated with an increased risk of HCC recurrence following OLT and has a potential clinical value for the prognosis of HCC patients treated with OLT.

Hepatitis C in African Americans

The care of hepatitis C virus (HCV) in African Americans represents an opportunity to address a major health disparity in medicine. In all facets of HCV infection, African Americans are inexplicably affected, including in the prevalence of the virus, which is higher among them compared with most of the racial and ethnic groups. Ironically, although fibrosis rates may be slow, hepatocellular carcinoma and mortality rates appear to be higher among African Americans. Sustained viral response (SVR) rates have historically significantly trailed behind Caucasians. The reasons for this gap in SVR are related to both viral and host factors. Moreover, low enrollment rates in clinical trials hamper the study of the efficacy of anti-viral therapy. Nevertheless, the gap in SVR between African Americans and Caucasians may be narrowing with the use of direct-acting agents. Gastroenterologists, hepatologists, primary care physicians, and other health-care providers need to address modifiable risk factors that affect the natural history, as well as treatment outcomes, for HCV among African Americans. Efforts need to be made to improve awareness among health-care providers to address the differences in screening and referral patterns for African Americans.

Expanded criteria donors

The greatest challenge facing liver transplantation today is the shortage of donor livers. Demand far exceeds supply, and this deficit has driven expansion of what is considered an acceptable organ. The evolving standard has not come without costs, however, as each new frontier of expanded donor quality (i.e., advancing donor age, donation after cardiac death, and split liver) may have traded wait-list for post-transplant morbidity and mortality. This article delineates the nature and severity of risk associated with specific deceased donor liver characteristics and recommends strategies to maximally mitigate these risks.