Barriers associated with the treatment of hepatitis C virus infection among illicit drug users
Introduction
In North America, Europe and Australia, >50% of prevalent and >75% of incident Hepatitis C virus (HCV) infections are associated with injection drug use (Shepard et al., 2005). Among long-term injection drug users (IDUs), the prevalence of HCV infection is 64–94% (Diaz et al., 2001, Patrick et al., 2001). Among those infected with HCV, the majority will develop persistent, chronic infection. Without treatment, fibrosis may develop over decades, potentially leading to cirrhosis, end-stage liver disease, hepatocellular carcinoma or death (Seeff, 2002). In Canada, a significant increase in HCV-related morbidity, mortality and economic cost burden indicators are expected for the coming years, constituting a major public health issue (El Saadany et al., 2005, Krahn et al., 2004).
Over the past decade, treatment for HCV – specifically combination treatment consisting of pegylated interferon and ribavirin – has been shown to be highly effective, achieving viral clearance rates (depending on genotype) between 55 and 85% (Fried et al., 2002, Manns et al., 2001). Until recently, HCV treatment guidelines in North America categorically excluded illicit drug users from consideration, citing concerns about adherence, susceptibility for side effects (e.g., depression), and re-infection risks (NIH, 1997). Several successful HCV treatment studies involving illicit drug users over the past years have challenged this paradigm (Backmund et al., 2001, Grebely et al., 2007d, Matthews et al., 2005, Sylvestre, 2005). Concretely, current HCV treatment guidelines in North America have now been revised to now stipulate consideration of treatment for HCV in this population on a “case-by-case” basis (Seeff and Hoofnagle, 2003, Sherman et al., 2004).
Despite these new considerations, several indicators suggest that few illicit drug users have received HCV treatment to date. In Vancouver, during the period 2000–2005 only 1.1% of a population of 1361 HCV antibody positive inner city residents reported having received treatment for HCV infection, despite it being freely available to them (Grebely et al., 2006, Grebely et al., 2007a). Similarly, in Australia only 4% of 2500 current IDUs attending needle exchange programs in 2003 had been treated for HCV, with only 0.6% actually on treatment at the time of the survey (NCHECR, 2003).
In some cases, this may be due to resource limitations. At the same time, specific factors intrinsic to the illicit drug user population influencing willingness or actual efforts for HCV treatment among illicit drug users may be at play. Large proportions of high-risk drug user populations remain uneducated about basic HCV risks and disease specifics, or are unaware of their disease status (Doab et al., 2005, Strauss et al., 2007). Several studies have indicated that between 50 and 80% of HCV infected drug users would be somewhat or strongly willing to undergo HCV treatment under the right circumstances (Doab et al., 2005, Fischer et al., 2005b, Stein et al., 2001, Strathdee et al., 2005). Specific enquiries have suggested that concerns about potential treatment side effects (e.g., depression) or requirements of simultaneous addiction treatment may reduce interest in HCV treatment, while perceptions of likely health complications from HCV, access to regular health or addiction care, and readiness for change concerning drug use are factors that have been associated with higher levels of interest in HCV treatment (Doab et al., 2005, Fischer et al., 2005b, Strathdee et al., 2005).
Given that illicit drug users are at the core of the present and future HCV epidemic in developed nations, any efforts to reduce the disease burden of HCV will include the development of systematic programs to increase treatment uptake in this group (Fischer et al., 2006). With these considerations in mind, we sought to evaluate barriers to initiating HCV treatment – including general treatment willingness – within a cohort of HCV-infected illicit drug users recruited from two inner city community health clinics in Vancouver and Victoria, British Columbia, Canada.
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Patients and methods
Study participants (n = 332) were recruited from two inner city community health clinics (CHC) in Vancouver and Victoria between June and December 2006: both centres are multi-disciplinary health care facilities providing primary care, addiction services and treatment of infectious diseases predominantly to marginalized individuals. Inclusion criteria were age >18 years and a history of illicit drug use. Study participants were recruited by way of convenience sampling from patients visiting the
Results
Key social, drug use and health characteristics of the analysis sample (n = 188) are presented in Table 1.
Of the sample (n = 188), 107 (56.9%) reported never having sought treatment for HCV infection and 96 (51.1%) reported having been offered treatment for HCV infection. In fact, 16.0% (n = 30) reported previously (n = 26) or currently (n = 4) receiving treatment for HCV infection. Of those not initiating treatment for HCV (n = 158), five refused to answer the questions about HCV treatment willingness. Of
Discussion
Effectively engaging marginalized individuals in HCV treatment is crucial for lowering the future HCV-related disease burden. The (self-reported) uptake of treatment for HCV infection in our study sample was 16%. This is higher than the rates previously reported among HCV-infected inner city residents in Vancouver (Grebely et al., 2006, Grebely et al., 2007a) and IDUs attending needle exchange programs in Australia (NCHECR, 2003), where only 1–4% have received HCV treatment. Our increased
Conflict of interest
Authors J.G. and B.C. have consulted for pharma company Hoffmann-La Roche and Schering Canada. All other authors declare that they have no conflicts of interest.
Acknowledgements
The authors thank Mrs. Michelle Firestone-Cruz and Ms. Eugenia Oviedo-Joekes for their assistance in protocol development, data collection or processing.
Funding. Funding for this study was provided by the Canadian Institutes for Health Research (J.G., J.D.R., B.F.), the National Canadian Research Training Program in Hepatitis C (NCRTP-HepC) (J.G., K.A.G.), British Columbia Medical Services Foundation (G.S.), Canadian Liver Foundation (G.D.), Association of Medical Microbiology and Infectious
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