[Economic evaluation of health care program for hepatitis C virus antibody screening]

We made a trial of introducing a health care program for hepatitis C virus (HCV) antibody screening in Saga prefecture, where mortality rate of hepatoma is one of the highest in Japan. The program started in 1992 and covered nearly the entire population older than 30 years in this prefecture. This was the first implementation in Japan. In the present study, we performed a cost-benefit analysis of this program. It included three steps; early detection of hepatitis C cases in the free-living population; implementation of interferon (IFN) therapy for detected chronic active hepatitis cases; follow-up of the cases who underwent IFN therapy. We counted, as cost, expenditure for primary screening, that for subsequent clinical examinations, that for IFN therapy, that for follow-up of detected HCV carriers, and loss of earned income during a leave of absence from work for the IFN therapy. On the other hand, we counted as benefit the medical expenditures saved, and gained earned income by reduction of hepatoma, cirrhosis and hepatitis due to medical intervention, both of which would have sustained losses had the health care program not been implemented. The employed model assumed age and gender specific natural histories for hepatitis C. The benefit/cost ratio was found to be in 1.71 to 2.32, suggesting economic validity of the proposed health care program. We further evaluated the economic validity by sensitivity analysis by changing rates of HCV carriers, discounting rates, rates of "complete responder" of chronic active hepatitis cases to IFN therapy, and detection rate of otherwise submerged chronic active hepatitis cases. Benefit/cost ratios were found to be greater than unity, given that the population rate of HCV carriers is higher than 1%.