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Study Finds Low Prevalence of HDV Antibody Positivity in Patients With Chronic HBV Infection
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Key Takeaways
- HDV/HBV co-infection significantly increases the risk of cirrhosis compared to HBV alone, with severe clinical outcomes.
- The study found a low HDV antibody positivity rate of 0.24% among patients with chronic HBV infection in China.
The prevalence of hepatitis D virus (HDV) antibody positivity was about 0.24% in patients with chronic hepatitis B virus (HBV).
The prevalence of hepatitis D virus (HDV) antibody positivity was generally low in patients with chronic hepatitis B virus (HBV) infection, according to study findings published in the Journal of Clinical and Translational Hepatology. The investigators noted that in-depth analyses of viral load, genotype, and clinical characteristics in patients with HDV RNA positivity, in addition to analyses of HDV infection dynamics, could further assist in developing effective treatment strategies and formulating public health policies.
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HDV and HBV co-infection is considered the most severe form of chronic viral hepatitis because of its unfavorable clinical outcomes, explained the study authors. HDV does not form its own viral envelope, relying on the surface glycoproteins of HBV to replicate. The global prevalence of HDV infection is estimated to be about 0.98%, whereas the prevalence of HDV among hepatitis B surface antigen (HBsAg)-positive patients is reported to be around 4.5% to 14.6%, according to the authors.
Chronic HBV/HDV co-infection accelerates the progression of hepatitis to a more severe stage compared with those who have HBV alone. The relative risk of developing cirrhosis doubles in patients with HDV/HBV co-infection compared with those with HBV alone, and approximately 15% of patients with HDV/HBV co-infection will develop cirrhosis within 1 to 2 years, and 70% to 80% within 5 to 10 years.
Large-scale data on the HDV/HBV co-infection rate is needed to estimate the current epidemiology of HDV in China, explained the authors. This study sought to estimate the current epidemiology of HDV. Patients from China with chronic HBV infection who had documented serum HBsAg positivity for more than 6 months were enrolled. Blood samples were collected at baseline for central evaluations of HDV antibody and HBsAg quantification. Additionally, assessments for hepatitis A virus (HAV), hepatitis C virus (HCV), hepatitis E virus (HEV), and HIV antibodies, as well as HDV RNA quantification, were performed in patients who tested positive for HDV antibodies. Serum samples were collected within 14 days following screening.
The study’s primary end points were the proportion of HDV infection (HDV antibody positivity) in patients with chronic HBV infection (part 1) and active HDV infection (positivity of both HDV antibody and HDV RNA) in patients with chronic HBV infection whose alanine aminotransferase (ALT) was greater than 40 U/L and HBV DNA was less than 104 IU/mL (part 2). Secondary end points included the proportion of patients positive for HDV RNA among those with HDV antibodies and their HDV RNA levels. Additionally, co-infection rates of HAV/HCV/HEV/HIV in patients with HDV antibodies, the associations between HBsAg and HDV RNA levels, and any risk factors for HDV infection were predefined exploratory end points.
A total of 5044 patients were enrolled between September 24, 2021, and December 28, 2022, but only 4936 patients were included in the final analysis. The mean age (± standard deviation) was about 42.9 ± 9.9 years, and the majority of patients (69.8%) were male. The mean ALT level was about 34 ± 58 U/L, and approximately 30.6% (n = 1509) of patients were hepatitis B e antigen-positive.
The mean HBsAg level at baseline was about 3535 ± 11,292 IU/mL among 4842 patients who were HBsAg positive. Additionally, the observed rate of HBV infection and HDV antibody positivity was about 0.24% (95% CI: 0.1%–0.4%), and only 1 patient of the studied population was HDV RNA positive. The authors observed that patients with HDV antibodies had statistically significantly lower levels of HBsAg compared with patients who were negative for HDV antibodies at baseline (mean: 1,032.6 ± 1,280.5 IU/mL [n = 12] vs. 3540.9 ± 11,305.0 IU/mL [n = 4,830]; p-value of Welch 2-sample t-test = 1.37 × 10−5).
The authors acknowledge several potential limitations, including a possible sample bias because patients were enrolled from only 9 hospitals. Additionally, there is a possibility of changes in patients’ HBV DNA and ALT statuses because data was collected up to 6 months prior to screening. There are also possible different detection methods or cutoffs for lab assessments across hospitals. Despite these limitations, the study authors emphasized that these findings provide an accurate assessment of HDV prevalence because of its larger patient population and broader geographical coverage. They state that future research should include other regions in China and conduct more in-depth analyses of HDV infection dynamics to further understand treatment and public health strategies.
