Testing and Epidemiology of Delta Hepatitis Among Asian Americans

Chronic hepatitis B (CHB) affects more than 257 million people world-wide with two-thirds of CHB infected people living in Asia and Sub-Saharan Africa. Although the overall prevalence of CHB is high in Asia, the regional prevalence varies; ranging from less than 0.5% in Japan to greater than 12% in Vietnam and Cambodia. Hepatitis delta virus (HDV) is a satellite virus that can infect individuals with hepatitis B virus (HBV) infection to the extent that at least 15-20 million people are conservatively estimated to be chronically infected with HBV and HDV. Chronic HBV/HDV infection is associated with more rapid progression to cirrhosis and a higher incidence of hepatocellular carcinoma (HCC) compared to patients with CHB mono-infection. Prevalence of chronic HBV/HDV remains high in Mongolia, the Mediterranean and Sub-Saharan countries and in the Amazon basin but the true prevalence remains to be determined among many populations and demic groups. Asian Americans are the fastest-growing minority group in the United States, comprising a heterogeneous population from more than 60 different ethnic groups speaking more than 100 different languages, exhibiting substantial socioeconomic diversity. While Asian Americans account for more than 60% of CHB infection in the United States, CHB prevalence varies among the ethnic groups. Similarly, prevalence of chronic hepatitis C and genotype distribution are different among the various Asian groups, underscoring the importance of disaggregating ethnic populations in hepatitis research. We recently reported the high prevalence of HDV infection among Mongolians living in Southern California. However, HDV infection among other Asian-American groups has not been studied, largely because outside of Mongolia and pockets in Vietnam, chronic HBV/HDV infection in Asia appears to below.

Recommendations for routine screening for HDV from various major professional liver societies are not consistent. Asian Pacific Association for the Study of the Liver (APASL) and the European Association for the Study of the Liver (EASL) recommend HDV screening for all HBsAg positive individuals. The American Association for the Study of Liver Diseases recommend testing of HBsAg positive individuals with "low or undetectable HBV DNA but high ALT levels", "persons who inject drugs, men who have sex with men, and immigrants from areas of high HDV with endemicity". However, the accurate prevalence of HDV infection in Asia is not well characterized.

To address this gap in knowledge, there is an important need to accurately characterize prevalence, clinical testing patterns and the epidemiology of HDV infection among disaggregated Asian-American groups.

This study will be conducted in 3 parts. The first part will involve a survey of hepatitis delta (HDV) testing practices among 100-125 physicians and other health care providers that have high volumes of Asian CHB patients. Special care will be made to include physicians and health care providers for patients across different Asian ethnic communities. Almost 45% of U.S. Asians live in the West with 30% residing in California alone. Chinese, Filipinos, Vietnamese and Koreans account for the 4 largest Southeast Asian groups but there are large communities of Thais, Cambodians and Burmese in Southern California and Hmongs in Central California. With over 150,000 Armenians residing in Los Angeles, this is another ethnic group that will be studied. Asian Pacific Liver Center (APLC) has worked closely with community CHB health care providers in previous studies and will build on these collaborations. In addition, APLC plans to collaborate with physicians from Texas (Vietnamese), Minnesota (Hmong) and New York City (Chinese, Koreans). In addition, physicians and providers from other settings will be surveyed; academic (USC, UCLA, Cedars-Sinai, Loma Linda, UCSD, UCSF, Stanford, NYU, Mount-Sinai, University of Hawaii, Southwestern, University of Minnesota) and large managed care organization (Southern California Kaiser, Veterans Administration and Sutter Health). Response to this survey will provide an overview of current practice of HDV testing and management among health care professionals with high numbers of Asian CHB patients and also develop a collaboration for subsequent objectives. Each survey responder will be asked to participate in the second and third parts of the study. Each responder will be individually engaged by the PI with respect to the association of hepatitis delta and chronic hepatitis B and the current guidelines and standards of practice for HDV testing among all CHB patients.

The second part involves a chart review of 50-60 physicians and other providers who follow a minimum of 100 CHB patients in their practice. A retrospective chart review will be performed of all 18 years and older CHB patients with the collection of demographic and clinical data including HDV testing results. These results will be compared with estimates based on physicians' responses to the survey. The data extraction will be performed by trained research coordinators familiar with chart reviews of CHB patients. The quality of data will be regularly monitored by the PI and Mimi Chang DNP (who has conducted CHB studies for more than 10 years).