Severity of liver disease in hepatitis C infection contracted through injecting drug use.

Background: Injecting drug use (IDU) is currently the most common route of hepatitis C virus (HCV) transmission in Australia and many other Western countries. Most reports on the natural history of HCV have examined populations that included patients from all risk groups, but it is possible that this increasingly important subgroup is different.

Aims: To assess the severity of liver disease in individuals who acquired HCV through IDU.

Methods: Three hundred and forty-six patients with confirmed HCV infection and a history of IDU, who had had a liver biopsy performed were recruited from a liver clinic. Demographic data, liver function tests and hepatitis B serology were obtained on all patients. A detailed drug use history and HCV viral studies were also available in a subgroup of 142 patients.

Results: Mean age of the group was 34 years and 73% were male. Mean duration of HCV infection was 14.6 years. Forty one per cent were infected with genotype 3a, 19% - 1a, 17% - 1 (nonsubtypable), 14% - 1b and 4% - 2b. Cirrhosis was present in 12% of patients. Patients with cirrhosis (38 years) were older than those with chronic hepatitis (34 years; p=0.0003) and had a longer duration of infection (17.2 vs 14.3 years; p=0.003). On multivariate analysis, however, patient age was the only factor independently associated with cirrhosis (odds ratio 4.2; 95% confidence interval 1.4-12.6).

Conclusion: While cirrhosis is less common in this group than in other HCV infected populations, its prevalence may increase as these patients are followed over a longer period of time.