title: Defining populations and injecting parameters among people who inject drugs: Implications for the assessment of hepatitis C treatment programs.
abstract: There is considerable interest in determining the impact that increased uptake of treatment for hepatitis C virus (HCV) infection will have on the burden of HCV among people who inject drugs (PWID). An understanding of the size of the population of PWID, rates of injecting cessation and HCV prevalence and incidence within the PWID population is essential for such exercises. However, these parameters are often uncertain. In this paper we review methods for estimating the size of the population of PWID and related parameters, taking into account the uncertainty that exists around data on the natural history of injecting drug use; consider issues in the estimation of HCV prevalence among PWID; and consider the importance of opioid substitution therapy and prisons as settings for the prevention and treatment of HCV infection among PWID. These latter two points are illustrated through examples of ongoing work in England, Scotland and Australia. We conclude that an improved understanding of the size of PWID populations, including current and former PWID and parameters related to injecting drug use and settings where PWID may be reached, is necessary to inform HCV prevention and treatment strategies.
authors: National Drug and Alcohol Research Centre, University of NSW, Sydney, Australia. Electronic address: s.larney@unsw.edu.au.
authors: Sarah
authors: S
authors: Larney
authors: Kirby Institute, University of NSW, Sydney, Australia.
authors: Jason
authors: J
authors: Grebely
authors: School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
authors: Matthew
authors: M
authors: Hickman
authors: Medical Research Council Biostatistics Unit, Cambridge, United Kingdom.
authors: Daniela
authors: D
authors: De Angelis
authors: Kirby Institute, University of NSW, Sydney, Australia.
authors: Gregory J
authors: GJ
authors: Dore
authors: National Drug and Alcohol Research Centre, University of NSW, Sydney, Australia.
authors: Louisa
authors: L
authors: Degenhardt
mesh_terms: D001315:Australia / Q000453:epidemiology; D004739:England / Q000453:epidemiology; D004812:Epidemiologic Methods; D006526:Hepatitis C / Q000453:epidemiology* / Q000628:therapy* / Q000635:transmission; D006801:Humans; D015994:Incidence; D058850:Opiate Substitution Treatment / Q000706:statistics & numerical data; D015995:Prevalence; D011330:Prisons / Q000706:statistics & numerical data; D011785:Quality Assurance, Health Care; D012606:Scotland / Q000453:epidemiology; D015819:Substance Abuse, Intravenous / Q000453:epidemiology* / Q000628:therapy
keywords: Hepatitis C virus; Modelling; People who inject drugs; Population estimation