All-cause and liver-related mortality among people who inject drugs with chronic hepatitis C virus infection in Oslo, Norway.

BACKGROUND

Data on mortality among people who inject drugs with hepatitis C virus (HCV) infection remain limited, particularly in settings with a high OAT coverage. We aimed to assess all-cause and liver-related mortality and to evaluate associations between key exposures and mortality among people who inject drugs with HCV infection.

METHODS

We included individuals evaluated for HCV treatment in a low-threshold clinic for people who inject drugs in Oslo, Norway, between 2013-2020 and linked data to the Norwegian Cause of Death Registry. Mortality was analysed using person-time, Poisson regression models to assess crude and adjusted IRRs, and Kaplan-Meier survival curves for subgroup comparison.

RESULTS

Among 506 individuals (27.8% female, median age 49.1 years, 77.0% recent injecting drug use, 15.9% liver cirrhosis, 77.8% HCV treatment uptake), 39 (7.7%) deaths were recorded. All-cause mortality was 2.11/100 PY (95% CI 1.50-2.88). Liver-related mortality was 1.07/100 PY (95% CI 0.22-3.12) among those with liver cirrhosis and 0.16/100 PY (95% CI 0.03-0.47) overall. Drug-induced deaths accounted for the largest proportion of deaths (28.2%). HCV treatment was associated with lower all-cause mortality (adjusted IRR 0.22 [95% CI 0.06-0.76]; p = 002), while liver cirrhosis was associated with increased mortality (adjusted IRR = 2.78 [95% CI 1.00-7.65]; p = 0.049).

CONCLUSION

Liver-related mortality among people who inject drugs with HCV cirrhosis was low. Mainly driven by drug-related deaths, all-cause mortality was higher among individuals with untreated HCV infection and among those with liver cirrhosis, underscoring the need for strategies that integrate HCV treatment with overdose prevention and access to broader healthcare.