Regional Comparisons of the Prevalence and Socioeconomics of Hepatitis Delta Virus in Two Southern California Counties

The global prevalence of chronic hepatitis D virus (HDV) is estimated to be 4%-5%. Our aim was to determine the prevalence of HDV exposure in patients with chronic hepatitis B (CHB) in three different healthcare systems based in San Diego (SD) County and Los Angeles (LA) County of California. We retrospectively reviewed all adult CHB patients screened for anti-HDV IgG antibody (HDV Ab) who were seen from 2010 to 2024 in the hepatology clinics at Scripps Clinic (SC) in La Jolla, California, and La Maestra Clinic (LM) in SD, and from 2019 to 2023 at UCLA. We determined the median household income by ZIP Code to stratify all patients by socioeconomic status (SES). At SC, 593 of 2441 patients with CHB were screened for HDV. A total of 14 patients tested positive for HDV Ab (2.4%). Two of the 14 patients had detectable HDV RNA. At LM, 118 of 312 patients with CHB were screened for HDV and three patients had a positive HDV Ab (2.5%). None had detectable HDV RNA. At UCLA, 234 of 267 patients with CHB were screened for HDV, and 10 patients had a positive HDV Ab (4.3%). One patient had detectable HDV RNA. Most patients screened at LM, SC, and UCLA belonged to the lowest median yearly income ($75,281), middle ($101,105), and high ($123,271) categories, respectively. There was no statistically significant difference in the prevalence of HDV Ab among each cohort. Of almost a thousand CHB patients who were screened for HDV exposure across three healthcare systems, the prevalence of HDV Ab-positive patients was 2.4%-4.3% without statistically significant differences. Patients from LM, SC, and UCLA were representative of low, middle, and high socioeconomic groups, respectively. This suggests that SES may be less of a risk factor for HDV infection. The HDV PCR-positive (chronic infection) rates were low, ranging from 0% to 0.4%.