Hepatitis D prevalence: problems with extrapolation to global population estimates

We read the meta-analysis of global hepatitis D prevalence by Chen et al and have some serious concerns relating to the proposed epidemiological estimates.1 Seroprevalence of hepatitis delta virus (HDV) was not adequately defined. In the methods, hepatitis delta antibody (anti-HDV), HDV RNA and HDV antigen (HDAg) were described as markers of HDV infection. In Supplementary Table S8, it is evident that total, IgG and IgM anti-HDV and HDAg were variably used to define HDV infection. HDAg is a transient marker of HDV infection, whereas IgM expression is inconsistently associated with both acute and chronic infection; neither are suitable epidemiological markers of chronic HDV infection.2 A total of 50 cohorts were used to inform the primary outcome, global HDV seroprevalence in the general population; of these, 30 were conducted in the last 20 years. The authors estimated …