Hepatitis E Infection in Patients With Inflammatory Bowel Diseases: A Systematic Review and Meta-Analysis

Opportunistic infections are increasingly recognised in patients with inflammatory bowel disease (IBD), particularly among those receiving immunosuppressive therapy. Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis worldwide, yet its relevance in IBD remains insufficiently clarified. This systematic review and meta-analysis aimed to explore the association between HEV infection and IBD. A comprehensive literature search was performed in PubMed/MEDLINE and Google Scholar up to May 2025, identifying all studies reporting HEV infection in patients with ulcerative colitis (UC) or Crohn's disease (CD), with or without a control group. Study quality was assessed using the Joanna Briggs Institute Checklist for Analytical Cross-Sectional Studies. Six eligible studies encompassing 1316 IBD patients were included in the qualitative and quantitative synthesis. The pooled prevalence of anti-HEV IgG (HEV-G) antibodies among IBD patients was 13.5%, though with notable heterogeneity. Anti-HEV IgM (HEV-M) and HEV-RNA positivity rates were significantly lower, at 1.9% and 0.03%, respectively. When compared with the general population, IBD patients exhibited similar HEV-G and HEV-M prevalence, and comparable rates were observed between UC and CD subgroups. In contrast, immunocompromised transplant recipients demonstrated markedly higher HEV seropositivity. Sensitivity analyses confined to European cohorts indicated a modest rise in HEV-G and HEV-M levels, particularly among patients receiving intensified immunosuppression. Clinically, unexplained elevations of liver enzymes in IBD should prompt consideration of HEV infection. Overall, HEV prevalence in IBD parallels that of the general population; however, severe immunosuppression may predispose to persistent infection or liver-related complications, warranting routine testing for accurate diagnosis.