Vietnamese American patients faced the highest risk of hepatocellular carcinoma (HCC) among racial and ethnic groups in a study of more than 4.2 million people, but the disparities narrowed when researchers looked specifically at patients with documented cirrhosis.
The findings, published in Clinical Gastroenterology and Hepatology, suggest that broad racial and ethnic categories may mask important differences in liver cancer risk. The researchers said disparities among patients without cirrhosis documented in their electronic health records (EHR) could stem from differences in hepatitis screening and treatment, cirrhosis diagnosis, or access to and delivery of health care.
Mindy C. DeRouen, PhD, MPH, of the Department of Epidemiology and Biostatistics at the University of California, San Francisco, and colleagues analyzed electronic health records from adults who received care at Sutter Health, Kaiser Permanente Hawai‘i, or the San Francisco Health Network between 2000 and 2016 or 2017. They linked the records to cancer registries to identify new cases of HCC and examined risk across 17 racial and ethnic groups, with separate analyses for men and women.
Among more than 4.2 million patients, 2,916 developed HCC. Compared with non-Hispanic white patients, Native Hawaiian or Pacific Islander patients had the greatest disparities. Both women and men were 2.4 times more likely to develop HCC than non-Hispanic White patients. Black women were 1.8 times more likely and Black men 1.5 times more likely to develop HCC. Risk was also higher among Asian American patients, at 1.7 times for women and 1.5 times for men, and Hispanic patients, at 1.5 times for women and 1.4 times for men.
How researchers grouped patients by race and ethnicity also affected the results. Their approach found disparities among Native Hawaiian or Pacific Islander patients, while a federal classification system found no increased risk among women in this group and only a slightly higher risk among men. The authors said these findings show how collpasing smaller populations into a catchall multiracial/multiethnic category can hide important disparities.
When Dr. DeRouen and colleagues grouped a subset of patients into more granular racial and ethnic categories, Vietnamese American patients had the greatest risk, with women 5.5 times more likely and men 5.4 times more likely to develop HCC. Native Hawaiian patients also had elevated risk, with women 3.6 times more likely and men 3.2 times more likely to develop HCC. Among patients reporting multiple Asian ethnicities, women were three times more likely and men 2.6 times more likely to develop HCC.
Cirrhosis status also made a difference. Disparities in HCC risk disappeared among women with documented cirrhosis and narrowed among men, but persisted among those without documented cirrhosis.
The authors cautioned that a lack of documented cirrhosis does not necessarily mean a patient did not have the condition. Only about 35% of patients who developed HCC had cirrhosis documented before their cancer diagnosis, well below the estimated 80% to 90% of HCC cases associated with cirrhosis. The researchers said gaps in medical records, fragmented care, and differences in access to health care may help explain the discrepancy.
Other limitations included the difficulty of fitting patients into mutually exclusive racial and ethnic categories, particularly those who reported more than one race or ethnicity. Race or ethnicity was also unknown for about one-quarter of eligible patients at Sutter Health and Kaiser Permanente Hawai‘i.
For physicians, the findings highlight the importance of hepatitis screening and treatment, liver disease management, and timely recognition of cirrhosis, particularly in populations at higher risk for HCC. The authors said improving these prevention efforts could help reduce racial and ethnic disparities in HCC.
The National Cancer Institute supported the study. The authors reported no conflicts of interest.
Expert Insight
Dr. DeRouen shared insights into the work with GI & Hepatology News.
Why were racial/ethnic disparities in HCC risk much smaller among patients with EHR-documented cirrhosis?
Dr. DeRouen: One possible explanation is that, once cirrhosis is clinically identified and recorded in the EHR, patients across racial/ethnic groups receive more comparable care for management of liver cancer risk factors (e.g., chronic hepatitis). However, there were far fewer than expected individuals with HCC for whom cirrhosis was EHR documented (35% in the study versus 80-90% expected HCC cases with cirrhosis), a pattern seen before in EHR-studies of cirrhosis. Thus, another possible explanation is that fragmented care is impacting whether cirrhosis is documented in the EHR such that remaining disparities in the group without EHR-documented cirrhosis represents underlying disparities in cirrhosis recognition, rather than varying patterns in racial/ethnic disparities for cirrhosis-related and cirrhosis-free HCC incidence.
How should these findings change HCC screening and hepatitis evaluation for high-risk racial and ethnic subgroups, particularly Vietnamese patients?
Dr. DeRouen: Our finding that Vietnamese males and females have the highest HCC risk compared to other racial/ethnic groups reinforces their known high burden of hepatitis B virus (HBV) infection, and that HBV screening in these high-risk groups should be proactive. Our study indicates additional high-risk ethnic groups, namely those who are Native Hawaiian, multiple Asian American ethnicities, Chinese American, Korean American, Black, and Hispanic. For some additional groups, risk level varies by sex. We are currently analyzing the risk factor profiles in these groups.
What is the biggest lesson for clinicians from using detailed, rather than broad, race and ethnicity categories?
Dr. DeRouen: The biggest lesson is that prior understanding of racial/ethnic disparities in risk using broad racial/ethnic categories may obscure additional distinct subpopulations that need increased attention. For example, using typical racial/ethnic categories, the non-Hispanic Native Hawaiian/Pacific Islander grouping did not show significantly elevated risk of HCC compared to the non-Hispanic White group. However, with our detailed race/ethnicity categorization, we observed very high risk for Native Hawaiians, that was second only to Vietnamese Americans.
Is there anything else you’d like to say about this work?
Dr. DeRouen: It is important to understand the clinical, behavioral, and social factors underlying racial and ethnic disparities. Our subsequent analyses of this same EHR-based cohort will examine the prevalence of HCC risk factors across detailed racial/ethnic groups and fraction of HCC attributable to those risk factors. Understanding differences in patterns of risk factors across groups could help to motivate proactive strategies to reduce HCC risk.