It is clear that HCV causes cirrhosis and hepatocellular carcinoma (HCC), although the rate at which these conditions develop, and the rate at which they cause death or the need for liver transplantation is unknown. In the U.S., it is estimated that 8,000 to 10,000 patients die annually of complications of HCV infection. Thus in Canada, we might expect, at maximum a death rate of about 800 to 1,000.

There are various estimates of the rate of development of cirrhosis, ranging from about 10% of hepatitis C carriers developing cirrhosis each decade, to an alternate estimate that about half of all HCV-infected patients will develop cirrhosis. Tong et al 19 have calculated that cirrhosis develops after a mean of about 20 years (SD 10 to 30 yrs) from initial infection via blood transfusion, and HCC develops a mean of eight years later. However, the population studied was highly selected, being those referred to a tertiary referral center with an interest in liver disease. It is likely that in the overall hepatitis C infected population, the mean rate of progression to cirrhosis and HCC is much lower.

Hepatocellular carcinoma is a recognized complication of hepatitis C. However, unlike hepatitis B, HCC rarely develops in the absence of cirrhosis in HCV-positive patients. The risk of HCC developing in chronic hepatitis C is variable in different studies. Hadziyannis et at 20 calculated odds ratios ranging between 6.3 and 13.7 in different study populations.

In a Japanese study the cumulative risk of a hepatitis C carrier developing HCC was 28% for males over 50 years of age and 6% for females over 50.21 Unfortunately, all data on the risk of HCC were obtained from retrospective studies. There are no prospective studies which can provide accurate estimates of the risk of HCC.

There is a pressing need for more accurate data on the prevalence of hepatitis C and on the mortality and morbidity of this disease. In particular studies are needed to obtain Canadian data.