Background and Aims: Drug-induced liver injury (DILI) presents with a wide phenotypic spectrum requiring an extensive differential diagnosis. Hepatitis E virus (HEV) is not systematically ruled out during acute hepatitis assessment in Spain. The aims of this study were to establish the role of HEV infection and its phenotypic presentation in patients initially suspected of DILI and to determine the anti-HEV seroprevalence rate. Methods: An analysis of 265 patients with suspected DILI and considered for enrolment in the Spanish DILI Registry and 108 controls with normal liver profiles was undertaken. Anti-HEV Immunoglobulin (Ig) G antibodies were analyzed in serum from all subjects. In those with serum samples extracted within 6 months from liver damage onset (n=144), HEV antigen (Ag) and anti- HEV IgM antibodies were tested in duplicate by ELISA. In addition, RT-PCR was performed externally in 8 patients. Results: Out of 144 patients, 12 (8%) were positive for anti-HEV IgM, mean age 61 years. Underlying hepatic diseases (OR=23.4, p20 folds upper limit of normal (OR=10.9, p=0.002) were associated with the diagnosis of acute hepatitis E. The overall anti-HEV IgG seroprevalence rate was 35%, evenly distributed between patients with suspected DILI (34%), and controls (39%). Conclusions: HEV seroprevalence and acute hepatitis E rates are relatively high in Spain. A search for active HEV infection is therefore advised in patients assessed for suspicion of DILI, particularly in patients with underlying liver diseases and high transaminase levels.The present study has been supported by grants of the Instituto de Salud Carlos III cofounded by Fondo Europeo de Desarrollo Regional FEDER (contract numbers: FIS PI0274-2016, PI-0285- 2016, PI 18-01804, PI 18-00901, PT17/0017/0020, CM17/00243, JR16/00015, B-0002-2019, UMA-18-FEDERJA-193 and by the Agencia Española del Medicamento. SCReN and CIBERehd are funded by Instituto de Salud Carlos III. European Cooperation in Science & Technology (COST) ACTION CA17112 Prospective European Drug-Induced Liver Injury Network, IMI2-Translational Safety Biomarker Pipeline (TransBioLine). The funding sources had no involvement in the study design, in the collection, analysis, and interpretation of data, in the writing of the report or in the decision to submit the manuscript for publicatio
