Quantifying the Contribution of Viral Hepatitis Control Policies and Improvement of Hepatitis C Treatment in Japan during 2000-2030 based on Simulation Modelling.

INTRODUCTION

Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are major causes of hepatocellular carcinoma (HCC) in Japan. The Japanese government has implemented various countermeasures since the early 2000s, including expanded screening and effective antiviral treatments. Evaluating the long-term impact of these policies is essential for guiding future strategies.

METHODS

We developed a Markov model-based simulation to estimate the annual transition of HBV/HCV carriers, disease progression, and HCC-related outcomes in Japan from 2000 to 2030. Five policy scenarios were set, reflecting the implementation stages of national countermeasures. A sensitivity analysis was also conducted by varying post-2020 hospital visit rates, the proportion of DAA treatment in chronic hepatitis/cirrhosis, and HCC mortality rates.

RESULTS

The simulation predicted a reduction in HCV carriers from 480,000 in Scenario 1 (no intervention) to 270,000 in Scenario 5 (reflecting 2020 policies). The number of chronic hepatitis and cirrhosis patients also declined significantly, mainly due to the introduction of direct-acting antivirals (DAAs). All scenarios showed a downward trend in new HCC cases and mortality; the decline was most pronounced in Scenario 5. Under Scenario 5, age-adjusted HCC mortality in 2030 was reduced by 53% compared to 2015 level. Sensitivity analysis revealed that variations in hospital visit rates, treatment proportions, and HCC mortality could lead to HCC deaths in 2030 ranging from 5,797 to 7,065.

DISCUSSION: Our findings suggest that sustained hepatitis countermeasures and the introduction of DAAs have significantly contributed to the decline in HCV-related disease burden in Japan. Simulation modeling provides a useful framework for evaluating past policies and projecting future outcomes.