Burden of chronic hepatitis B and C infections in 2015 and future trends in Japan: A simulation study

Abstract

Background: Determining the number of chronic hepatitis B (HBV) and C virus (HCV) infections is essential to assess the progress towards the World Health Organization 2030 viral hepatitis elimination goals. Using data from the Japanese National Database (NDB), we calculated the number of chronic HBV and HCV infections in 2015 and predicted the trend until 2035.

Methods: NDB and first-time blood donors data were used to calculate the number of chronic HBV and HCV infections in 2015. A Markov simulation was applied to predict chronic infections until 2035 using transition probabilities calculated from NDB data.

Findings: The total number of chronic HBV and HCV infections in 2015 in Japan was 1,905,187-2,490,873 (HCV:877,841-1,302,179, HBV:1,027,346-1,188,694), of which 923,661-1,509,347 were undiagnosed or diagnosed but not linked to care ("not engaged in care"), and 981,526 were engaged in care. Chronic HBV and HCV infections are expected to be 923,313-1,304,598 in 2030, and 739,118-1,045,884 in 2035. Compared to 2015, by 2035, the number of persons with HCV not engaged in care will decline by 59·8 - 76·1% and 86·5% for patients in care. For HBV, a 47·3 - 49·3% decrease is expected for persons not engaged in care and a decline of 26·0% for patients engaged in care.

Interpretation: Although the burden of HBV and HCV is expected to decrease by 2035, challenges in controlling hepatitis remain. Improved and innovative screening strategies with linkage to care for HCV cases, and a functional cure for HBV are needed.

Funding: Japan Ministry of Health, Labour and Welfare.

Keywords: AC, asymptomatic carrier; Bepatitis B; C-LC, compensated liver cirrhosis; CH, chronic hepatitis; D-LC, decompensated liver cirrhosis; DAA, direct-acting antiviral; Gepatitis C; HBV, hepatitis B virus, HCV, hepatitis C virus; HCC, hepatocellular carcinoma; ICD, International classification of diseases; IFN, interferon; Japan; LC, liver cirrhosis; MHLW, Ministry of health labour; MTCT, mother-to-child transmission; Markov model; NA, nucleos(t)ide analogues; NDB, national database, SVR, sustained virologic rate, WHO, World Health Organization; Prediction.

Figure 1

Transition pathway of liver disease. This figure shows the transition pathway of liver disease for HCV (Figure 1A) and HBV (Figure 1B) based on the natural history of liver disease [Asymptomatic carriers (AC), Chronic Hepatitis (CH), Liver Cirrhosis (LC), and Hepatocellular Carcinoma (HCC)] and classified into groups of undiagnosed and diagnosed but not linked to care, and patients engaged in care (on treatment or clinical monitoring only). Dashed lines represent changes between the groups, and straight lines notify the progression in liver disease. Death is the absorbing state and is classified into liver-related deaths and deaths from other causes.

Figure 2

Breakdown of the number of chronic HBV and HCV infections in Japan in 2000 and 2015. Distribution of the number of persons living with chronic HBV and HCV infections in 2015 compared to previously published results in 2000. In 2015, chronic HBV and HCV infections were classified into two groups (undiagnosed and patients engaged in care), whereas in 2015 they were classified into six groups: undiagnosed, diagnosed but not linked to care, patients engaged in care (on clinical monitoring only or treatment), newly infected, cured, and deaths.

Figure 3

Trends in chronic HBV and HCV infections between 2015 and 2035 by simulation. Simulation of the dynamics of chronic HCV (Figure 3A) and HBV (Figure 3B) infections between 2015 and 2035, based on Markov model. Left and middle graphs show the lower estimates of the cumulative number of chronic infections (left) and the distribution of chronic infections by liver disease state (middle). Right graphs represent the trend in the number of undiagnosed, diagnosed but not linked to care, and patients engaged in care until 2035, compared to previously published results in 2000 and 2011.