Disparities in Access to Liver Transplant Referral and Evaluation among Patients with Hepatocellular Carcinoma in Georgia

Liver transplantation offers the best survival for patients with early-stage hepatocellular carcinoma (HCC). Prior studies have demonstrated disparities in transplant access; none have examined the early steps of the transplant process. We identified determinants of access to transplant referral and evaluation among patients with HCC with a single tumor either within Milan or meeting downstaging criteria in Georgia.Population-based cancer registry data from 2010 to 2019 were linked to liver transplant centers in Georgia. Primary cohort: adult patients with HCC with a single tumor ≤8 cm in diameter, no extrahepatic involvement, and no vascular involvement. Secondary cohort: primary cohort plus patients with multiple tumors confined to one lobe. We estimated time to transplant referral, evaluation initiation, and evaluation completion, accounting for the competing risk of death. In sensitivity analyses, we also accounted for non-transplant cancer treatment.Among 1,379 patients with early-stage HCC in Georgia, 26% were referred to liver transplant. Private insurance and younger age were associated with increased likelihood of referral, while requiring downstaging was associated with lower likelihood of referral. Patients living in census tracts with ≥20% of residents in poverty were less likely to initiate evaluation among those referred [cause-specific hazard ratio (csHR): 0.62, 95% confidence interval (CI): 0.42-0.94]. Medicaid patients were less likely to complete the evaluation once initiated (csHR: 0.53, 95% CI: 0.32-0.89).Different sociodemographic factors were associated with each stage of the transplant process among patients with early-stage HCC in Georgia, emphasizing unique barriers to access and the need for targeted interventions at each step.

SIGNIFICANCE

Among patients with early-stage HCC in Georgia, age and insurance type were associated with referral to liver transplant, race, and poverty with evaluation initiation, and insurance type with evaluation completion. Opportunities to improve transplant access include informing referring providers about insurance requirements, addressing barriers to evaluation initiation, and streamlining the evaluation process.

Geography, inequities, and the social determinants of health in transplantation

Among the causes of inequity in organ transplantation, geography is oft-cited but rarely defined with precision. Traditionally, geographic inequity has been characterized by variation in distance to transplant centers, availability of deceased organ donors, or the consequences of allocation systems that are inherently geographically based. Recent research has begun to explore the use of measures at various geographic levels to better understand how characteristics of a patient's geographic surroundings contribute to a broad range of transplant inequities. Within, we first explore the relationship between geography, inequities, and the social determinants of health. Next, we review methodologic considerations essential to geographic health research, and critically appraise how these techniques have been applied. Finally, we propose how to use geography to improve access to and outcomes of transplantation.

Racial and ethnic disparities in psychosocial evaluation and liver transplant waitlisting

Health disparities have been well-described in all stages of the liver transplantation (LT) process. Using data from psychosocial evaluations and the Stanford Integrated Psychosocial Assessment, our objective was to investigate potential racial and ethnic inequities in overall LT waitlisting and not waitlisting for medical or psychosocial reasons. In a cohort of 2271 candidates evaluated for LT from 2014 to 2021 and with 1-8 years of follow-up, no significant associations were noted between race/ethnicity and overall waitlisting and not waitlisting for medical reasons. However, compared with White race, Black race (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.07-2.56) and Hispanic/Latinx ethnicity (OR, 2.10; 95% CI, 1.16-3.78) were associated with not waitlisting for psychosocial reasons. After adjusting for sociodemographic variables, the relationship persisted in both populations: Black (OR, 1.95; 95% CI, 1.12-3.38) and Hispanic/Latinx (OR, 2.29; 95% CI, 1.08-4.86) (reference group, White). High-risk Stanford Integrated Psychosocial Assessment scores were more prevalent in Black and Hispanic/Latinx patients, likely reflecting upstream factors and structural racism. Health systems and LT centers should design programs to combat these disparities and improve equity in access to LT.

Factors Associated With Geographic Disparities in Gastrointestinal Cancer Mortality in the United States

BACKGROUND & AIMS

Significant geographic variability in gastrointestinal (GI) cancer-related death has been reported in the United States. We aimed to evaluate both modifiable and nonmodifiable factors associated with intercounty differences in mortality due to GI cancer.

METHODS

Data from the Centers for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research platform were used to calculate county-level mortality from esophageal, gastric, pancreatic, and colorectal cancers. Multivariable linear regression models were fit to adjust for county-level covariables, considering both patient (eg, sex, race, obesity, diabetes, alcohol, and smoking) and structural factors (eg, specialist density, poverty, insurance prevalence, and colon cancer screening prevalence). Intercounty variability in GI cancer-related mortality explained by these covariables was expressed as the multivariable model R².

RESULTS

There were significant geographic disparities in GI cancer-related county-level mortality across the US from 2010-2019 with the ratio of mortality between 90th and 10th percentile counties ranging from 1.5 (pancreatic) to 2.1 (gastric cancer). Counties with the highest 5% mortality rates for gastric, pancreatic, and colorectal cancer were primarily in the Southeastern United States. Multivariable models explained 43%, 61%, 14%, and 39% of the intercounty variability in mortality rates for esophageal, gastric, pancreatic, and colorectal cancer, respectively. Cigarette smoking and rural residence (independent of specialist density) were most strongly associated with GI cancer-related mortality.

CONCLUSIONS

Both patient and structural factors contribute to significant geographic differences in mortality from GI cancers. Our findings support continued public health efforts to reduce smoking use and improve care for rural patients, which may contribute to a reduction in disparities in GI cancer-related death.

Listing at non-local transplant centers is associated with increased access to deceased donor kidney transplantation

The ability of kidney transplant candidates to travel outside of their usual place of care varies by sociodemographic factors, potentially exacerbating disparities in access. We used Transplant Referral Regions (TRRs) to overcome previous methodological barriers of using geographic distance to assess the characteristics and outcomes of patients listed for kidney transplant at centers in neighboring TRR or beyond neighboring TRRs. Among listed kidney transplant candidates, 20.9% traveled to a neighbor and 5.6% beyond a neighbor. A higher proportion of travelers were White, had some college education, and lived in ZIP codes with lower poverty. Travel to a neighbor was associated with a 7% increase in likelihood of deceased donor transplant (cHR: 1.07, 95% CI: 1.05, 1.09) and traveling beyond a neighbor with a 19% increase (cHR: 1.19, 95% CI: 1.15, 1.24). Travelers had similar rates of living donor transplant and waitlist mortality as patients who did not travel; those who traveled beyond a neighbor had slightly lower posttransplant mortality (HR: 0.91, 95% CI: 0.83, 0.99). In conclusion, the ability to travel outside of the recipient's assigned TRR increases access to transplantation and improves long-term survival.

Epidemiology beyond its limits

In 1995, journalist Gary Taubes published an article in Science titled "Epidemiology faces its limits," which questioned the utility of nonrandomized epidemiologic research and has since been cited more than 1000 times. He highlighted numerous examples of research topics he viewed as having questionable merit. Studies have since accumulated for these associations. We systematically evaluated current evidence of 53 example associations discussed in the article. Approximately one-quarter of those presented as doubtful are now widely viewed as causal based on current evaluations of the public health consensus. They include associations between alcohol consumption and breast cancer, residential radon exposure and lung cancer, and the use of tanning devices and melanoma. This history should inform current debates about the reproducibility of epidemiologic research results.

Understanding gastrointestinal cancer mortality disparities in a racially and geographically diverse population

BACKGROUND

Gastrointestinal (GI) cancers represent a diverse group of diseases. We assessed differences in geographic and racial disparities in cancer-specific mortality across subtypes, overall and by patient characteristics, in a geographically and racially diverse US population.

METHODS

Clinical, sociodemographic, and treatment characteristics for patients diagnosed during 2009-2014 with colorectal cancer (CRC), pancreatic cancer, hepatocellular carcinoma (HCC), or gastric cancer in Georgia were obtained from the Surveillance, Epidemiology, and End Results Program database. Patients were classified by geography (rural or urban county) and race and followed for cancer-specific death. Multivariable Cox proportional hazards models were used to calculate stratified hazard ratios (HR) and 95% confidence intervals (CIs) for associations between geography or race and cancer-specific mortality.

RESULTS

Overall, 77% of the study population resided in urban counties and 33% were non-Hispanic Black (NHB). For all subtypes, NHB patients were more likely to reside in urban counties than non-Hispanic White patients. Residing in a rural county was associated with an overall increased hazard of cancer-specific mortality for HCC (HR = 1.15, 95% CI = 1.02-1.31), pancreatic (HR = 1.11, 95% CI = 1.03-1.19), and gastric cancer (HR = 1.17, 95% CI = 1.03-1.32) but near-null for CRC. Overall racial disparities were observed for CRC (HR = 1.18, 95% CI = 1.11-1.25) and HCC (HR = 1.12, 95% CI = 1.01-1.24). Geographic disparities were most pronounced among HCC patients receiving surgery. Racial disparities were pronounced among CRC patients receiving any treatment.

CONCLUSION

Geographic disparities were observed for the rarer GI cancer subtypes, and racial disparities were pronounced for CRC. Treatment factors appear to largely drive both disparities.

Variation in Racial Disparities in Liver Transplant Outcomes Across Transplant Centers in the United States

Little is known about the role that transplant centers may play in perpetuating racial disparities after liver transplantation, which are unexplained by patient-level factors. We examined variation in between-center and within-center disparities among 34,114 Black and White liver transplant recipients in the United States from 2010 to 2017 using Scientific Registry of Transplant Recipient (SRTR) data. We used Cox proportional hazards models to calculate transplant center-specific Black-White hazard ratios and hierarchical survival analysis to examine potential effect modification of the race-survival association by transplant center characteristics, including transplant volume, proportion of Black patients, SRTR quality rating, and region. Models were sequentially adjusted for clinical, socioeconomic, and center characteristics. After adjustment, Black patients experienced 1.11 excess deaths after liver transplant per 100 person-years compared with White patients (95% confidence interval [CI], 0.65-1.56), corresponding to a 21% increased mortality risk (95% CI, 1.12-1.31). Although there was substantial variation in this disparity across transplant centers, there was no evidence of effect modification by transplant center volume, proportion of minority patients seen, quality rating, or region. We found significant racial disparities in survival after transplant, with substantial variation in this disparity across transplant centers that was not explained by selected center characteristics. This is the first study to directly evaluate the role transplant centers play in racial disparities in transplant outcomes. Further assessment of the qualitative factors that may drive disparities, such as selection processes and follow-up care, is needed to create effective center-level interventions to address health inequity.

County Differences in Liver Mortality in the United States: Impact of Sociodemographics, Disease Risk Factors, and Access to Care

BACKGROUND AND AIMS

Data have demonstrated state-wide variability in mortality rates from liver disease (cirrhosis + hepatocellular carcinoma), but data are lacking at the local level (eg, county) to identify factors associated with variability in liver disease-related mortality and hotspots of liver disease mortality.

METHODS

We used Centers for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research data from 2009 to 2018 to calculate county-level, age-adjusted liver disease-related death rates. We fit multivariable linear regression models to adjust for county-level covariates related to demographics (ie, race and ethnicity), medical comorbidities (eg, obesity), access to care (eg, uninsured rate), and geographic (eg, distance to closest liver transplant center) variables. We used optimized hotspot analysis to identify clusters of liver disease mortality hotspots based on the final multivariable models.

RESULTS

In multivariable models, 61% of the variability in among-county mortality was explained by county-level race/ethnicity, poverty, uninsured rates, distance to the closest transplant center, and local rates of obesity, diabetes, and alcohol use. Despite adjustment, significant within-state variability in county-level mortality rates was found. Of counties in the top fifth percentile (ie, highest mortality) of fully adjusted mortality, 60% were located in 3 states: Oklahoma, Texas, and New Mexico. Adjusted mortality rates were highly spatially correlated, representing 5 clusters: South Florida; Appalachia and the eastern part of the Midwest; Texas and Oklahoma; New Mexico, Arizona, California, and southern Oregon; and parts of Washington and Montana.

CONCLUSIONS

Our data demonstrate significant intrastate differences in liver disease-related mortality, with more than 60% of the variability explained by patient demographics, clinical risk factors for liver disease, and access to specialty liver care.

Kidney transplant program waitlisting rate as a metric to assess transplant access

Kidney transplant program performance in the United States is commonly measured by posttransplant outcomes. Inclusion of pretransplant measures could provide a more comprehensive assessment of transplant program performance and necessary information for patient decision-making. In this study, we propose a new metric, the waitlisting rate, defined as the ratio of patients who are waitlisted in a center relative to the person-years referred for evaluation to a program. Furthermore, we standardize the waitlisting rate relative to the state average in Georgia, North Carolina, and South Carolina. The new metric was used as a proof-of-concept to assess transplant-program access compared to the existing transplant rate metric. The study cohorts were defined by linking 2017 United States Renal Data System (USRDS) data with transplant-program referral data from the Southeastern United States between January 1, 2012 and December 31, 2016. Waitlisting rate varied across the 9 Southeastern transplant programs, ranging from 10 to 22 events per 100 patient-years, whereas the program-specific waitlisting rate ratio ranged between 0.76 and 1.33. Program-specific waitlisting rate ratio was uncorrelated with the transplant rate ratio (r = -.15, 95% CI, -0.83 to 0.57). Findings warrant collection of national data on early transplant steps, such as referral, for a more comprehensive assessment of transplant program performance and pretransplant access.

Abstract PO-168: Association between geography and cause-specific mortality in gastrointestinal cancers in Georgia

Background: Cancers of the gastrointestinal system represent a diverse range of diseases with different etiologies, from screening-detectable colorectal cancer (CRC) to pancreatic cancer, often diagnosed at late stage and highly lethal. While racial disparities have been observed for some of these cancers, the impact of geography is less understood. Georgia is an ideal place to examine disparities in geography because it has a diverse setting and population, with approximately 25% of residents living in a rural area and nearly one-third identifying as non-Hispanic Black (NHB), according to the 2010 decennial census. Methods: We obtained clinical (age at diagnosis, tumor stage, tumor size), sociodemographic (e.g., insurance status, marital status, SES index), and treatment information (e.g., receipt of surgery, lymph node biopsy/removal) on nearly 30,000 NHB and non-Hispanic White (NHW) men and women aged 18 years and older, diagnosed with CRC, hepatocellular carcinoma (HCC), pancreatic cancer or gastric cancer between 2009 and 2014 in Georgia from the population-based Surveillance, Epidemiology, and End Results (SEER) Program.

Patients were classified as residing in a metro or non-metro county at diagnosis according to 2013 rural-urban continuum codes. Multivariable Cox proportional hazards models were used to calculate the hazard ratios (HRs) and corresponding 95% confidence intervals (95% CI) for the association between residing in a non- metro versus metro county and cause-specific mortality, stratified by patient characteristics. Results: Over 75% of the study population resided in a metro county at diagnosis, with the highest proportion among HCC cases (81%) and the lowest proportion among CRC cases (76%). Overall, NHBs were more likely to reside in metro counties (82%) than NHWs (74%). The average length of follow-up varied by cancer site and metro status, ranging from 35 months (CRC in metro areas) to 4 months (pancreatic cancer in non-metro areas). For all cancer sites, patients in metro counties were more likely to be younger, single, have localized disease (except gastric cancer), and receive surgery of the primary site. By comparison, patients in non-metro counties were more likely to be diagnosed at older ages, have Medicaid, and be widowed. Residing in a non-metro county was associated with higher cause- specific mortality among the youngest patients (age 18-49 years) for pancreatic cancer (HR=1.4, 95% CI: 1.1, 1.9) and gastric cancer (HR=1.8, 95% CI: 1.2, 2.6). We also observed a higher hazard of mortality for residing in a non-metro compared to metro county among NHB HCC patients (HR=1.3, 95% CI: 1.0, 1.7) and never married gastric cancer patients (HR=1.5, 95% CI: 1.1, 2.1). Associations among CRC patients were less robust. Conclusion: Our results suggest residing in a non-metro county is associated with higher mortality among some groups diagnosed with rarer gastrointestinal cancers. Geographic differences in access to diagnosis and treatment may contribute to this disparity.

Citation Format: Rebecca Nash, Jasmine M. Miller-Kleinhenz, Maria C. Russell, Lindsay J. Collin, Katherine Ross-Driscoll, Jeffrey M. Switchenko, Lauren E. McCullough. Association between geography and cause-specific mortality in gastrointestinal cancers in Georgia [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-168.