ReviewNon-injection drug use and Hepatitis C Virus: A systematic review
Introduction
Hepatitis C Virus (HCV) infection is a leading risk for liver disease, affecting more than 170 million people globally according to the World Health Organization (1998). Since the virus was first isolated in 1989, injection drug users (IDUs) have been found to be at high risk for contracting the virus (Hagan, 1998, Hocking et al., 2001, Roy et al., 2002).
However, the evidence regarding the relationship between HCV infection and non-injecting users of drugs such as crack, methamphetamines and powder cocaine or heroin is ambiguous and controversial. Some researchers have suggested that non-injecting drug users (NIDUs) are often injecting drug users (IDUs) who have failed to report their route of administration accurately (Judd et al., 2002), or that HCV transmission in NIDUs is associated with tattooing (Howe et al., 2005) or unsafe sexual behavior (Gyarmathy et al., 2002). Hypothesized drug-related risk factors for acquisition of HCV in NIDUs include sharing of non-injection drug use equipment, such as straws or crack pipes (Gyarmathy et al., 2002, Howe et al., 2005, Tortu et al., 2004).
Quantifying the magnitude of the problem and understanding practices associated with HCV acquisition among NIDUs with more accuracy could lead to better informed and more effective prevention. Our goals were to perform a systematic review of the literature summarizing HCV prevalence in NIDUs and to critically evaluate evidence on risk of HCV in NIDUs by examining these data in relation to study methods and hypothesized risk factors.
Section snippets
Literature review
As part of the HCV Synthesis Project (a meta-analysis of HCV epidemiology and prevention in drug users), searches of published literature were carried out on MEDLINE, ISI Web of Knowledge databases (Thomson Scientific, 2006), PsychInfo, ERIC, Dissertation Abstracts, Sociological Abstracts, and Current Contents. We used the following search terms: (hepatitis C OR HCV) AND (intravenous drug abuse OR intravenous drug use OR drug misuse OR drug addict OR injecting drug use OR drug abuse OR IDU) AND
Study characteristics
We found 28 published reports that met our criteria (Allwright et al., 2000, Baozhang et al., 1997, Broers et al., 1998, Chang et al., 1999, Denis et al., 2000, Feldman et al., 2000, Fuller et al., 2004, Galperim et al., 2004, Garten et al., 2004, Gyarmathy et al., 2002, Harsch et al., 2000, Hershow et al., 1998, Howe et al., 2005, Koblin et al., 2003, Lai et al., 2001, Maayan et al., 1994, Mathei et al., 2005, Njoh and Zimmo, 1997, Nyamathi et al., 2002, Quaglio et al., 2003a, Quaglio et al.,
Summary of findings
Our systematic review identified 28 published studies of HCV in self-reported NIDUs. Prevalence of HCV in never-injecting drug users ranged from 2.3 to 35.3% in studies from several regions with samples that included between 20 and 722 NIDU participants. When we restricted the sample to reports that were least likely to misclassify NIDUs, prevalence estimates ranged between 2.3 and 17%. Whether the higher observed prevalence rates (up to 35%) in studies that were less focused on NIDUs is
Conclusions
Despite this relative scarcity of information, those who work with drug user populations are creating interventions to protect non-injection users of illicit drugs. For example, a study from Canada (Shannon et al., 2006) describes efforts in Vancouver to encourage safe crack cocaine smoking. Those who work with NIDUs would benefit from stronger evidence to help inform their efforts to reduce drug-related harm.
We conclude that current studies have not clearly demonstrated whether or not
Acknowledgments
This research was funded by NIDA Grant Number R01 DA018609. Sommer Rentmeesters provided research assistance on the initial construction of the tables. The authors would like to thank colleagues at the Center for Drug Use and HIV Research (funded by Grant Number P30 DA011041) for their support and assistance.
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