Hepatitis E virus infection in a single center in Japan

Hepatitis E virus (HEV) is an emerging cause of acute hepatitis in developed countries. Older adults may be prone to symptomatic disease due to age-related vulnerability or underlying conditions. Limited data exist regarding risk factors, clinical outcomes, and liver fibrosis markers in elderly populations.

We conducted a single-center retrospective review between January 1, 2016, and March 31, 2025. Patients diagnosed with acute HEV infection were included. The FIB-4 index was calculated 3-6 months after clinical recovery and used as a descriptive, exploratory indicator rather than a diagnostic test.

Eight patients met the inclusion criteria, with a median age of 68 years (IQR: 63.5-70.5); six (75%) were male. One asymptomatic case was identified through routine blood donor screening. Comorbidities included hypertension (n = 3) and diabetes mellitus (n = 1). Two patients reported regular alcohol consumption. Among symptomatic patients, the median FIB-4 index was 2.00 (IQR: 1.65-3.08), compared to 1.61 in the asymptomatic patient. Six patients required hospitalization for a median of 17.5 days (IQR: 12-27). One patient received steroid pulse therapy. All patients recovered, with no progression to chronic hepatitis.

In this small cohort, most HEV cases occurred in older men. Post-recovery FIB-4 values were numerically higher among symptomatic cases, but this observation is descriptive and hypothesis-generating; the FIB-4 index should not be used during the acute phase. HEV should be considered in older adults presenting with acute liver dysfunction, regardless of dietary or travel history, and fibrosis assessment - when clinically indicated - should rely on comprehensive noninvasive approaches rather than a single score.