Research paper
Trends in hepatitis C antibody prevalence among Aboriginal and Torres Strait Islander people attending Australian Needle and Syringe Programs, 1996–2015

https://doi.org/10.1016/j.drugpo.2017.06.007Get rights and content

Abstract

Background

Research indicates that hepatitis C antibody (anti-HCV) prevalence is higher among Australian Aboriginal and Torres Strait Islander (Aboriginal) than non-Aboriginal people who inject drugs (PWID). We examined trends in demographic and drug use characteristics and anti-HCV prevalence among Australian Needle and Syringe Program Survey (ANSPS) respondents by Aboriginal status from 1996 to 2015.

Methods

The ANSPS survey involved collecting demographic, behavioural data and a dried blood spot for anti-HCV testing. We used logistic regression to determine demographic and behavioural factors associated with testing anti-HCV positive in the following time-periods (1996–2000, 2001–2005, 2006–2010, 2011–2015) among Aboriginal and non-Aboriginal PWID respondents.

Results

Overall, there were 16,948 PWID, with 11% identifying as Aboriginal. The proportion of Aboriginal respondents increased from 7% in 1996–2000 to 16% in 2011–2015. Overall anti-HCV prevalence was significantly higher among Aboriginal (60%) than non-Aboriginal PWID (52%, p < 0.01). Receptive syringe sharing (RSS) declined among non-Aboriginal PWID (p < 0.001) over time, however among Aboriginal PWID, RSS remained stable (p = 0.619). Factors independently associated with testing positive for anti-HCV among Aboriginal PWID in 2011–2015 were 16 or more years since first injection (adjusted odds ratio [AOR] 6.04, p < 0.001), history of incarceration (AOR: 1.74, p = 0.010) and currently or previously on opioid substitution therapy (AOR: 1.89, p = 0.003). Compared to 1996–2000, testing anti-HCV positive was significantly associated with the time-periods: 2001–2005 (unadjusted odds ratio [OR]: 1.39, p < 0.001), 2006–2010 (OR: 1.38, p < 0.001) and 2011-2015 (OR: 1.25, p < 0.001) among non-Aboriginal PWID; however this increase did not occur among Aboriginal PWID.

Conclusion

The proportion of Aboriginal PWID attending Needle Syringe Programs appears to have increased. Overall, the prevalence of anti-HCV has remained higher among Aboriginal than non-Aboriginal PWID. Coupling increased access to NSPs with new interferon-free HCV treatments and culturally appropriate education and counselling services could influence new HCV infections among Aboriginal PWID.

Introduction

Aboriginal and Torres Strait Islander (Aboriginal) people are Australia’s first peoples and have a strong and resilient history (Australian Institute of Health and Welfare, 2015; Commonwealth of Australia). Compared with non-Aboriginal people, Aboriginal people have poorer health and economic outcomes including higher rates of chronic and communicable diseases and unemployment, lower levels of home ownership, school completion and life expectancy (Australian Institute of Health and Welfare, 2015). Although Aboriginal people comprise ∼3% of the Australian population; in 2015 they comprised 27% of Australia’s prison population (Australian Bureau of Statistics, 2016). In 2015 the incarceration rate per 100,000 was 2346 among Aboriginal people compared with 154 among non-Aboriginal people (Australian Bureau of Statistics, 2016).

In Australia, injecting drug use accounts for the majority of new hepatitis C virus (HCV) infections (Sievert et al., 2011). Exposure to the virus can be determined via a diagnostic test for HCV antibodies. Although the majority of people exposed to HCV will become chronically infected, around one in four of those exposed will spontaneously clear the virus (Grebely et al., 2014). In 2015, an estimated 227,000 people were living with chronic HCV infection in Australia (Kirby Institute, 2016). Although data on the proportion of Aboriginal people living with chronic HCV is unavailable, the rate of newly diagnosed HCV per 100,000 population is consistently higher among Aboriginal compared with non-Aboriginal people (165 vs. 40/100,000 respectively) (Kirby Institute, 2016). Untreated individuals with chronic HCV can develop cirrhosis and hepatocellular carcinoma (HCC), with the incidence of HCC estimated to be two to eight times higher among Aboriginal compared with non-Aboriginal people in Australia (Cunningham, Rumbold, Zhang, & Condon, 2008).

There are 3554 Needle and Syringe Programs (NSPs) in Australia, including 102 primary, 786 secondary and 2311 pharmacy NSPs and 300 syringe dispensing machines (Iversen, Linsen, Kwon, & Maher, 2017). In 2015–2016, these services distributed a total 49.5 million needles and syringes (Iversen, Linsen, et al., 2017), and between 2000 and 2009, an estimated 96,667 new HCV infections were prevented as a result of NSPs (Kwon et al., 2012). Primary NSPs are stand-alone or co-located services that have NSP as their primary aim. They employ dedicated harm reduction staff, offer education and referrals services and dispense the majority of injecting equipment in Australia. Although there is a significant body of evidence regarding injection behaviour that increases the risk of exposure to HCV infection (De, Roy, Boivin, Cox, & Morissette, 2008; Nelson et al., 2011), we do not know if prevalence of HCV infection or risk behaviours have changed over time among Aboriginal people who inject drugs (PWID) attending NSPs. This study aims to fill these gaps by examining (1) trends in HCV antibody (anti-HCV) prevalence, demographic and risk behaviours among Aboriginal PWID who attended Australian NSPs from 1996 to 2015 to assist clinicians, researchers and policy makers develop targeted interventions to reduce the burden of HCV and HCC among Aboriginal people; and (2) factors associated with anti-HCV infection among Aboriginal and non-Aboriginal PWID.

Section snippets

Study population

The Australian Needle and Syringe Program Survey (ANSPS) is an annual serial cross-sectional survey, conducted at ∼50 NSPs from all states and territories (Fig. 1). Survey sites were recruited based on NSP client occasions of service per week, willingness to participate and representation from all states and territories. Due to the sentinel nature of the ANSPS, survey sites were recruited if they were in close proximity to drug markets and had a high volume of NSP consumers. Over a 1–2 week

Results

Between 1996 and 2015, 16,948 PWID consented to participate in the ANSPS. Overall, 11% were Aboriginal, 66% were male, 22% were aged <25 years, 57% had a history of OST and 49% injected daily or more frequently (Table 1). The proportion of Aboriginal ANSPS respondents increased significantly from 7% in 1996–2000 to 16% in 2011–2015 (p-trend < 0.001).

Overall, the prevalence of anti-HCV was significantly higher among Aboriginal compared with non-Aboriginal respondents (60.2% vs. 52.2% respectively, p

Discussion

Overall, there was an increase in the proportion of Aboriginal PWID attending the ANSPs and the prevalence of anti-HCV was higher among Aboriginal compared with non-Aboriginal PWID. Some similar trends in demographic characteristics and drug use were observed among Aboriginal and non-Aboriginal PWID over the past two decades. Aboriginal and non-Aboriginal PWIDs were older and had longer histories of injection drug use in more recent years. Both groups were more likely to have a history of

Conclusions

While it may be encouraging to see a significant increase in Aboriginal PWID accessing NSPs, this is of concern if it reflects an underlying increase in the population of Aboriginal PWID. The prevalence of anti-HCV and the sharing of needles and syringes remained high among Aboriginal PWID over the last two decades. Coupling access to NSPs with new interferon-free HCV treatments and culturally appropriate education and counselling services, including provision of OST in custodial settings could

Conflict of interests

None declared.

Acknowledgements

Simon Graham and Michael Doyle are Aboriginal Australians. All authors acknowledge the contribution staff at the Australian Needle and Syringe Program sites make to the prevention of hepatitis C and HIV in Australia. Simon Graham is supported by an Australian-American Fulbright postdoctoral scholarship, a McKenzie postdoctoral fellowship and the Melbourne Poche Centre for Indigenous Health at the University of Melbourne. Jenny Iversen and Lisa Maher are supported by National Health and Medical

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