Seroprevalence of hepatitis D among hepatitis B-infected patients attending the viral hepatitis treatment unit in Alexandria, Egypt: a prospective cross-sectional observational study

Background Hepatitis D virus (HDV) infection accelerates liver illness progression in hepatitis B surface antigen (HBsAg)-positive individuals, yet its prevalence in Alexandria, Egypt, is unknown. Methods We carried out a prospective cross-sectional observational study on 158 HBsAg-positive adults attending the Alexandria University Viral Hepatitis Treatment Unit (Sept 2022–Aug 2023). All underwent clinical, laboratory, and imaging assessment, and serum total anti-HDV antibodies were detected by ELISA. Results Anti-HDV antibodies were detected in 19.6% (31/158) of patients (95% CI, 13.4%-26.8%). HDV-positive patients were older (mean 50.9 ± 12.0 vs. 45.3 ± 11.6 years, p = 0.024), had higher ALT (median 38 vs. 32 U/L, p = 0.010) and AST (median 40 vs. 31 U/L, p = 0.009), more frequent significant fibrosis (74.2% vs. 51.2%, p = 0.021), and lower HBV DNA levels (median 0.04 vs. 0.70 × 10³ IU/mL, p = 0.017). Hepatic encephalopathy was more common across HDV-positive participants (12.9% vs. 1.6%, p = 0.014). Conclusion Nearly one in five HBsAg-positive patients in Alexandria, Egypt, had evidence of HDV exposure, with associations suggesting more advanced liver injury. These findings support universal HDV screening among all HBsAg-positive individuals in Egypt. Clinical trial number Not applicable.