All-cause and liver-related mortality in hepatitis C infected drug users followed for 33 years: a controlled study

The course of chronic hepatitis C virus (HCV) in injecting drug users (IDUs) has not been well described. The aim of this study was to compare long-term all-cause and liver-related mortality among anti-HCV positive IDUs with and without persisting HCV infection.

A retrospective-prospective controlled cohort design was applied. All IDUs admitted to resident drug treatment (1970-1984) and with available stored sera were screened for anti-HCV antibody. Anti-HCV positive individuals were further tested for the presence of HCV RNA. All-cause and liver-related mortality was compared between HCV RNA positive (n=328) and HCV RNA negative individuals (n=195). The observation was accomplished through register linkage to national registers. Mean observation time was 33 years.

All-cause mortality rate was 1.85 (95% CI 1.62-2.11) per 100 person-years, male 2.11 (95% CI 1.84-2.46), female 1.39 (95% CI 1.07-1.79). Mortality rates were not influenced by persisting HCV infection. Main causes of death were intoxications (45.0%), suicide (9.1%), and accidents (8.2%). Liver disease was the cause of death in 7.5% of deaths among HCV RNA positive subjects. Five of 13 deaths among male IDUs with persisting HCV infection occurring after the age of 50 years were caused by liver disease.

The all-cause mortality in IDUs is high and with no difference between HCV RNA positive and HCV RNA negative individuals, the first three decades after HCV transmission. However, among IDUs with chronic HCV infection who have survived until 50years of age, HCV infection emerges as the main cause of death.