Estimating population attributable risk for hepatitis C seroconversion in injecting drug users in Australia: implications for prevention policy and planning
Article first published online: 5 OCT 2009
© 2009 The Authors. Journal compilation © 2009 Society for the Study of Addiction
Volume 104, Issue 12, pages 2049–2056, December 2009
How to Cite
Wand, H., Spiegelman, D., Law, M., Jalaludin, B., Kaldor, J. and Maher, L. (2009), Estimating population attributable risk for hepatitis C seroconversion in injecting drug users in Australia: implications for prevention policy and planning. Addiction, 104: 2049–2056. doi: 10.1111/j.1360-0443.2009.02704.x
- Issue published online: 9 NOV 2009
- Article first published online: 5 OCT 2009
- Submitted 23 February 2009; initial review completed 4 May 2009; final version accepted 4 June 2009
- Hepatitis C virus;
- injecting drug use;
- population attributable risk
Objective To determine risk factors and estimate their population-level contribution to hepatitis C virus (HCV) burden.
Methods Established and potentially modifiable risk factors were estimated using partial population attributable risk (PARp) in a cohort of new injecting drug users (IDUs) in Sydney, Australia.
Results A total of 204 hepatitis C seronegative IDUs were recruited through street-based outreach, methadone clinics and needle and syringe programmes (NSPs) and followed-up at 3–6-monthly intervals. A total of 61 HCV seroconversions were observed during the follow-up [overall incidence rate of 45.8 per 100 person-years (95% confidence interval: 35.6–58.8)]. Overall, five potentially modifiable risk factors (sharing needles/syringes, sharing other injecting equipment, assisted injecting, frequency of injection and not being in drug treatment) accounted for approximately 50% of HCV cases observed.
Conclusion While sharing needles/syringes or other injecting equipment were associated most strongly with increased risk of HCV infection, the PARp associated with these behaviours was relatively modest (12%) because they are relatively low-prevalence behaviours. Our analyses suggest that more HCV infection could be avoided by changing more common, but less strongly associated behaviours such as assisted injecting or daily injecting. Results suggest that to have a very substantial effect on HCV, a range of risk factors need modifying. The most efficient use of scarce resources in reducing HCV infections will require complex balancing between the PAR for a given risk factor(s), the efficacy of interventions to actually modify the risk factor, and the cost of these interventions.