Masayuki Ohisa

Seroprevalence, genotypic distribution and potential risk factors of hepatitis B and C virus infections among adults in Siem Reap, Cambodia

We investigated hepatitis B virus (HBV) and hepatitis C virus (HCV) infections among adults in Siem Reap, Cambodia, to consider the prevention strategy in cooperation with the Ministry of Health in Cambodia.

High prevalences of hepatitis B and C virus infections among adults living in Binh Thuan province, Vietnam.

Vietnam is one of the countries with the highest mortality from liver cancer, which is mostly attributed to hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. For planning preventive strategies against these infections, we investigated prevalences of HBV and HCV infections among adults living in Binh Thuan, Vietnam.

Predicting future blood supply and demand in Japan with a Markov model: application to the sex- and age-specific probability of blood donation

Simulation studies were performed to predict the future supply and demand for blood donations, and future shortfalls.

Estimated numbers of patients with liver disease related to hepatitis B or C virus infection based on the database reconstructed from medical claims from 2008 to 2010 in Japan

To estimate the number of patients with liver‐related diseases classified by hepatitis viruses (HBV, HCV) based on the information from re‐coded medical claims including several diagnosed diseases.

Validation and limitation of age-period-cohort model in simulating mortality due to hepatocellular carcinoma from 1940 to 2010 in Japan.

We aimed to simulate the mortality due to hepatocellular carcinoma (HCC) by the age–period–cohort (APC) model with use of sex‐ and age‐specific mortality data, for the purpose of validating the utility and assessing the limitation of this model.

The association of hepatitis C virus infection with the prognosis of chronic hemodialysis patients: A retrospective study of 3,064 patients between 1999 and 2010

The prevalence of hepatitis C virus (HCV) infection is high among patients receiving chronic hemodialysis. To clarify the risk ratio of HCV infection with respect to mortality and prognosis in chronic hemodialysis patients, a retrospective longitudinal cohort study was conducted in 2010 and involved 3,064 patients receiving chronic hemodialysis at nine dialysis facilities in Hiroshima, Japan, who were recruited from 1999 to 2003. Logistic regression and Cox hazards models were used to estimate the mortality risk among hemodialysis patients. Among the patients, 422 (14.0%) were positive for HCV RNA. HCV RNA positivity was associated with death in the logistic model (adjusted odds ratio = 1.79; P < 0.001). However, it was not a risk factor for the reduced of survival rate in the Cox proportional hazard model (adjusted risk ratio = 1.07; P = 0.4138). In summary, among hemodialysis patients, HCV RNA is correlated with the mortality rate; however, it is not significantly correlated with prognosis in terms of survival time. On the other hand, diabetes and age at dialysis onset are significantly correlated with survival. Diabetes control treatment should be preferentially selected for hemodialysis patients, and antiviral therapy for HCV should be introduced based on the clinical state of the patient. J. Med. Virol. 87:1558–1564, 2015.

Hepatitis B virus infection in hemodialysis patients in Japan: Prevalence, incidence and occult hepatitis B virus infection.

A survey of hepatitis B virus (HBV) infection in hemodialysis (HD) patients was conducted to determine the burden and risk of infection and to suggest preventive measures against HBV infection among HD patients at nine hospitals in Hiroshima, Japan, from 1999 to 2003.

Reduced prevalence of hepatitis B surface antigen positivity among pregnant women born after the national implementation of immunoprophylaxis for babies born to hepatitis B virus-carrier mothers in Japan

We aimed to estimate hepatitis B surface antigen (HBsAg) positivity among birth year‐stratified pregnant women in Hiroshima, Japan, and compare prevalence rates between women born before and after implementation of a national immunoprophylactic vaccination program for babies born to hepatitis B virus (HBV) carrier mothers in Japan.

Trends in the total numbers of HBV and HCV carriers in Japan from 2000 to 2011

We estimated the total number of undiagnosed HBV and HCV carriers and patients with hepatitis virus‐related disease in Japan according to 6 different groups classified by their natural histories during 2011. In 2011, the total number of carriers and patients infected with HBV or HCV was estimated according to 6 groups using government reports and reports from the hepatitis epidemiology research group of The Ministry of Health, Labor and Welfare in Japan. In 2011, the total number of hepatitis virus carriers was estimated to be 2 090 128‐2 840 128 in which the estimated number of undiagnosed HCV and HBV carriers was 776 826 (HBV: 481 470; HCV: 295 356). The total number of treated patients, as either inpatients or outpatients, was estimated to be 811588 (HBV: 303 366; HCV: 520 600) in 2011. It is presumed that many carriers shirk consultation for many reasons, such as patients’ misunderstanding, lack of awareness and forgetfulness of their positive status. The numbers of infected patients who did not seek treatment increased gradually to 501 714‐1 251 714 (HBV: 333 791‐483 791; HCV: 167 923‐767 923) in 2011. Compared to 2000, the number of undiagnosed carriers was significantly reduced in 2011 probably because of the well‐organized, effective national hepatitis virus screening system that has been launched by the Japanese government since 2002. Moreover, the increase in the number of untreated persons who are aware of their positive status shows that more effort should be invested in improving the referral system from screening centres to core hospitals.

Natural course of persistent hepatitis B virus infection in hepatitis B e antigen-positive and hepatitis B e antigen-negative cohorts in Japan based on the Markov model: YAMASAKI et al.

This population‐based study examined the natural course of hepatitis B e antigen (HBeAg)‐positive or HBeAg‐negative persistent hepatitis B virus (HBV) infection, adjusted by age and liver disease states using a Markov model. Using 12 417 person‐years data (n = 862), annual transition probabilities were estimated, and age‐adjusted cumulative incidence and natural history of persistent HBV infection were simulated in both sexes of groups 1 (HBeAg‐negative status with HBV DNA level <4.0 log IU/mL at entry) and 2 (persistent HBeAg‐positive status throughout the study). In group 1, 15.26% of 30‐years old men with chronic hepatitis (CH) were expected to remain in the same state at age 65 years, 28.32% subsided into an hepatitis B surface antigen (HBsAg)‐negative state, and 13.20% developed hepatocellular carcinoma (HCC). The expectations for 40‐years old men in group 1 were 21.43%, 19.86%, and 15.04%, respectively. The expectations for 30 years women in group 1 were 30.57%, 21.15%, and 4.08%, respectively. These results suggest that HBeAg positivity caused a higher risk of HCC onset in persistent HBV infection after adjustments for age, sex, and liver disease state. HCC was likely to develop, but unlikely to subside into HBsAg clearance, remaining in a CH state with aging, regardless of HBeAg state. Furthermore, both HCC development and HBsAg clearance occurred more frequently in men than in women, irrespective of HBeAg status.