The role of immigration in chronic hepatitis B and C in Asturias - Origin and characteristics of the patients. An observational, cross-sectional study.

Objective: To understand the burden of immigration in chronic hepatitis B (CHB) and C (CHC) in our setting and the characteristics of immigrants with each infection.

Materials and methods: An observational, descriptive, and cross-sectional study that included all patients attended for CHB (n=758) and CHC (n=1,673) between January 2014 and December 2023. Demographic, epidemiological, and clinical variables were analyzed.

Results: The proportion of immigrants was higher in CHB than in CHC (38.8% vs. 5.6%; P<0.001), as well as among incident cases compared to prevalent ones, both in CHB (60.7% vs. 23.1%; p<0.001) and CHC (7.8% vs. 2.6%; p<0.001). The geographic area with the highest proportion of CHB was sub-Saharan Africa (33.3%), and for CHC it was Eastern Europe (40.4%). The main known mechanism of infection was vertical-familial transmission (28.2%) in CHB and injecting drug use (21.3%) in CHC. Compared with those with CHB, immigrants with CHC were older (51.6 vs. 34 years; p<0.001), consumed alcohol more frequently (16% vs. 3.7%; p<0.001), had a higher BMI (26.7 vs. 24.5 kg/m²; p=0.03), and greater liver stiffness (7.9 vs. 5.2 kPa; p<0.001) evaluated by transient elastography.

Conclusions: Immigration plays a growing role in hepatitis B and C in our setting, making systematic screening in this population necessary. Although the impact of immigration is much greater in CHB than in CHC, immigrants with CHC present a more advanced stage of liver fibrosis.