Racial and ethnic disparities in access to liver transplantation

Abstract

Access to liver transplantation is reportedly inequitable for racial/ethnic minorities, but inadequate adjustments for geography and disease progression preclude any meaningful conclusions. We aimed to evaluate the association between candidate race/ethnicity and liver transplant rates after thorough adjustments for these factors and to determine how uniform racial/ethnic disparities were across Model for End-Stage Liver Disease (MELD) scores. Chronic end-stage liver disease candidates initially wait-listed between February 28, 2002 and February 27, 2007 were identified from Scientific Registry for Transplant Recipients data. The primary outcome was deceased donor liver transplantation (DDLT); the primary exposure covariate was race/ethnicity (white, African American, Hispanic, Asian, and other). Cox regression was used to estimate the covariate-adjusted DDLT rates by race/ethnicity, which were stratified by the donation service area and MELD score. With averaging across all MELD scores, African Americans, Asians, and others had similar adjusted DDLT rates in comparison with whites. However, Hispanics had an 8% lower DDLT rate versus whites [hazard ratio (HR) = 0.92, P = 0.011]. The disparity among Hispanics was concentrated among patients with MELD scores < 20, with HR = 0.84 (P = 0.021) for MELD scores of 6 to 14 and HR = 0.85 (P = 0.009) for MELD scores of 15 to 19. Asians with MELD scores < 15 had a 24% higher DDLT rate with respect to whites (HR = 1.24, P = 0.024). However, Asians with MELD scores of 30 to 40 had a 46% lower DDLT rate (HR = 0.54, P = 0.004). In conclusion, although African Americans did not have significantly different DDLT rates in comparison with similar white candidates, race/ethnicity-based disparities were prominent among subgroups of Hispanic and Asian candidates. By precluding the survival benefit of liver transplantation, this inequity may lead to excess mortality for minority candidates.

Figure 1

Apparent Deficit in Liver Transplant Access for African-Americans is Confounded by Geography in the MELD Era. This figure demonstrates the differences in relative transplant rates between African-Americans and Whites when compared using three different methods of geographic adjustment. When adjusting for geography by grouping adjacent OPTN regions together, or even by individual OPTN regions, African-Americans appeared to have a significantly lower liver transplant rate compared to Whites in those same geographic areas. The DSA is the primary geographic unit of liver allocation in the United States. When comparing African-Americans and Whites registered in the same DSA, no differences in access to liver transplantation from the waiting list are noted.

Figure 2

Racial/Ethnic Variation in Relative Liver Transplant Rates in the MELD Era. Based on DSA-level and other risk-adjustment, the relative transplant rates for Hispanics are significantly lower than Whites. African-Americans had relatively similar transplant rates compared to Whites, as in Figure 1. Despite a small trend toward a 3% higher transplant rate for Asians compared to Whites, this was not significant. For Other or mixed race candidates, there was a non-significant trend toward a 3% lower liver transplant rate compared to Whites. The models incorporated all changes in MELD score reported to the SRTR.

Figure 3

Relative Liver Transplant Rates by Race/Ethnicity and MELD Score. After further stratifying each racial group by MELD score, several findings were prominent. African-Americans did not have significantly different transplant rates compared to Whites at any MELD score. Hispanic candidates had significantly lower transplant rates compared to Whites with similar disease severity at MELD scores less than 20, by 15–16%. Asian candidates demonstrated 24% higher liver transplant rates at the lowest MELD scores, but 46% lower transplant rates at the highest MELD scores. Of note, the analysis incorporated all changes in MELD score reported to the SRTR, and these transplant rate differences reflect the outcomes while candidates remained at the MELD score within that range.

Figure 4

Regional Variation in Access to Liver Transplantation for Minority Candidates. Across all minority groups, the 11 OPTN regions that cover the United States demonstrated an impressive degree of variation in relative transplant rates compared to White candidates. Four regions demonstrated significantly different transplant rates for a minority group compared to Whites. Five regions trended toward lower transplant rates for African-Americans compared to Whites in those respective regions. Five regions demonstrated trends toward lower liver transplant rates for Hispanics, and Region 2 reached statistical significance in this regard. For Asian candidates, seven regions trended toward lower access to liver transplantation compared to Whites. Regions 9 and 10 had much lower transplant rates for these candidates compared to their respective White counterparts, but Region 3 had significantly higher transplant rates for Asians. The analysis incorporated all changes in MELD score reported to the SRTR,