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 …

中文翻译：

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丁型肝炎流行率：外推到全球人口估计的问题

我们阅读了 Chen 等人对全球丁型肝炎流行率的荟萃分析，并对提议的流行病学估计值有一些严重的担忧。1 丁型肝炎病毒 (HDV) 的血清阳性率没有得到充分定义。在这些方法中，丁型肝炎抗体（抗HDV）、HDV RNA和HDV抗原（HDAg）被描述为HDV感染的标志物。在补充表 S8 中，很明显，总的、IgG 和 IgM 抗 HDV 和 HDAg 被不同地用于定义 HDV 感染。HDAg 是 HDV 感染的瞬时标志物，而 IgM 表达与急性和慢性感染的相关性不一致；两者都不是慢性 HDV 感染的合适流行病学标志物。2 总共使用了 50 个队列来告知主要结果，即一般人群中的全球 HDV 血清阳性率；其中，30 次是在过去 20 年中进行的。