Differential HCC risk among HBV indeterminate types at baseline and by phase transition.

Background: Patients with chronic hepatitis B (CHB) with indeterminate phase make up a diverse cohort with likely different outcomes.

Objective: We compared the hepatocellular carcinoma (HCC) risk in indeterminate CHB with different baseline types and by phase transition.

Design: This was a retrospective cohort study of 1986 (94.2% Asian) patients with indeterminate CHB from nine countries/regions. Patients were classified according to baseline hepatitis B e-antigen (HBeAg), alanine aminotransferase (ALT) and HBV DNA. The cumulative HCC incidence was compared.

Results: Based on the 2018 American Association for the Study of Liver Disease guidance, most indeterminate patients were HBeAg negative (84.9%). The 20-year HCC incidence was highest in type 1 (HBeAg positive, ALT<1×upper limit of normal (ULN), HBV DNA 20 000-10 IU/mL, 36.2%) and lowest in type 8 (HBeAg negative, ALT 1-2×ULN, HBV DNA<2000 IU/mL, 1.9%). The 20-year HCC incidence of those who remained indeterminate was 4.7%. Cumulative HCC incidence rates were high in patients with indeterminate CHB who transitioned to immune tolerant (15 years: 16.5%) or immune active (20 years: 13.7%) phase but low for those who transitioned to immune inactive phase (20 years: 2.5%). In multivariable analysis, compared with type 8, higher HCC risk was seen with HBeAg-positive type 1 (adjusted HR (aHR)=40.1, p<0.001), type 2 (ALT 1-2×ULN, HBV DNA≥20 000 IU/mL, aHR=25.1, p<0.001), HBeAg-negative type 9 (ALT>2×ULN, HBV DNA<2000 IU/mL, aHR=4.6, p=0.032) and type 10 (ALT<1×ULN, HBV DNA<2000 IU/mL but with moderate to severe inflammation/fibrosis, aHR=7.3, p=0.033). Similar directions in HCC risks were found in analyses based on the 2017 European Association for the Study of the Liver guideline.

Conclusion: Several types of indeterminate CHB had high HCC risk. These data support the potential expansion of treatment criteria for higher risk types of indeterminate CHB.