922
Effect of Hepatitis C Virus and HIV Infections on Mortality among Illicit Drug Users
Jason Grebely*1, J Raffa2, B Conway1, C Lai3, M Krajden4, M Tyndall1,3, and M Tyndall1,3
1Univ of British Columbia, Vancouver, Canada; 2Univ of Waterloo, Canada; 3BC Ctr for Excellence in HIV/AIDS, Vancouver, Canada; and 4BC Ctr for Disease Control, Vancouver, Canada
Background: Morbidity and mortality associated with hepatitis
C virus (HCV) infection is becoming of increasing concern among those co-infected
with HIV and HCV. With this in mind, we sought to determine the impact of HCV
and HIV infections on mortality in illicit drug users.
Methods: CHASE is a cohort study of inner city residents
recruited from January 2003 to June 2004. HIV and HCV status were determined
through linkage with provincial databases. Mortality data were derived from the
BC Vital Statistics registry (2003-2005). Reported International Classification
of Diseases (ICD-10) codes determined the underlying cause of death. In each
category (HIV–/HCV–, HIV–/HCV+, HIV+/HCV–,
HIV+/HCV+), natural cause mortality rates and mortality
due to HIV and HCV were calculated.
Results: Of 2069 participants, we identified 721 HCV–/HIV–,
962 HCV+/HIV–, 33 HCV–/HIV+, and 353
HCV+/HIV+ subjects. Among 82 deaths, common causes of
death were HIV infection (25.6%) and unnatural causes (19.5%). The natural
cause mortality rate was 15.5 deaths/1000 person-years overall (n = 66), 9.6 deaths/1000 person-years
for HCV–/HIV– (n
= 15), 11.0 deaths/1000 person-years for HCV+/HIV– (n = 28), 30.4 deaths/1000 person-years for
HCV–/HIV+ (n = 2),
and 37.8 deaths/1000 person-years for HCV+/HIV+ subjects
(n = 37). Among HCV–/HIV+
and HCV+/HIV– subjects, mortality attributed to HIV and
HCV was 15.2 and 2.0 deaths/1000 person-years. In HCV+/HIV+
subjects, mortality attributed to HIV and HCV were 25.6 and 1.3 deaths/1000 person-years.
Overall, Cox proportional hazards analyses demonstrated that natural cause mortality
was associated with HIV infection (adjusted HR 5.3, 3.0 to 9.7, p <0.001), age (HR 1.8/10-year
increase, 1.3 to 2.4, p <0.001)
and aboriginal ethnicity (HR 1.7, 0.96 to 3.0, p = 0.07), and not associated with HCV infection (HR 1.0, 0.50 to 2.0,
p = 0.99).
Conclusions: In this large retrospective analysis, mortality
rates in illicit drug users were high, with HIV infection leading to a 5-fold increase
in risk of mortality. Due to the timing of the HCV epidemic in this population,
there has been little impact of HCV on mortality to date. However, without
programs to treat HCV in this group, we expect a significant increase in
mortality attributable to HCV infection.
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