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Rapid decline in HCV incidence among people who inject drugs associated with national scale-up in coverage of a combination of harm reduction interventions.

Palmateer NE, Taylor A, Goldberg DJ, Munro A, Aitken C, Shepherd SJ, McAllister G, Gunson R, Hutchinson SJ - PLoS ONE (2014)

Bottom Line: We observed a decline in HCV incidence, per 100 person-years, from 13.6 (95% CI: 8.1-20.1) in 2008-09 to 7.3 (3.0-12.9) in 2011-12; a period during which increases in the coverage of OST and IEP, and decreases in the frequency of injecting and sharing of injecting equipment, were observed.Individual-level evidence demonstrated that combined high coverage of needles/syringes and OST were associated with reduced risk of recent HCV in analyses that were unweighted (AOR 0.29, 95%CI 0.11-0.74) and weighted for frequency of injecting (AORw 0.05, 95%CI 0.01-0.18).This is the first study to demonstrate that impressive reductions in HCV incidence can be achieved among PWID over a relatively short time period through high coverage of a combination of interventions.

View Article: PubMed Central - PubMed

Affiliation: Blood-borne Viruses and Sexually Transmitted Infections Section, Health Protection Scotland, Glasgow, United Kingdom.

ABSTRACT

Background: Government policy has precipitated recent changes in the provision of harm reduction interventions - injecting equipment provision (IEP) and opiate substitution therapy (OST) - for people who inject drugs (PWID) in Scotland. We sought to examine the potential impact of these changes on hepatitis C virus (HCV) transmission among PWID.

Methods and findings: We used a framework to triangulate different types of evidence: 'group-level/ecological' and 'individual-level'. Evidence was primarily generated from bio-behavioural cross-sectional surveys of PWID, undertaken during 2008-2012. Individuals in the window period (1-2 months) where the virus is present, but antibodies have not yet been formed, were considered to have recent infection. The survey data were supplemented with service data on the provision of injecting equipment and OST. Ecological analyses examined changes in intervention provision, self-reported intervention uptake, self-reported risk behaviour and HCV incidence; individual-level analyses investigated relationships within the pooled survey data. Nearly 8,000 PWID were recruited in the surveys. We observed a decline in HCV incidence, per 100 person-years, from 13.6 (95% CI: 8.1-20.1) in 2008-09 to 7.3 (3.0-12.9) in 2011-12; a period during which increases in the coverage of OST and IEP, and decreases in the frequency of injecting and sharing of injecting equipment, were observed. Individual-level evidence demonstrated that combined high coverage of needles/syringes and OST were associated with reduced risk of recent HCV in analyses that were unweighted (AOR 0.29, 95%CI 0.11-0.74) and weighted for frequency of injecting (AORw 0.05, 95%CI 0.01-0.18). We estimate the combination of harm reduction interventions may have averted 1400 new HCV infections during 2008-2012.

Conclusions: This is the first study to demonstrate that impressive reductions in HCV incidence can be achieved among PWID over a relatively short time period through high coverage of a combination of interventions.

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Related in: MedlinePlus

Analytical framework of potential associations between harm reduction interventions and HCV transmission.The arrows represent investigated associations: relationships A through C are group-level and relationships D through M are individual-level.
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pone-0104515-g001: Analytical framework of potential associations between harm reduction interventions and HCV transmission.The arrows represent investigated associations: relationships A through C are group-level and relationships D through M are individual-level.

Mentions: The difficulties in undertaking what would traditionally be considered ‘robust’ study designs to investigate public health interventions have been well documented [13]–[15]. Nevertheless, some common themes that have emerged from such evaluations, in relation to causal attribution, are (i) the importance of understanding the processes/pathways between intervention(s) and outcome(s) [16] and (ii) the combination of evidence generated from different non-experimental study designs [17]. The analytical approach applied here borrows from these themes: first, to understand pathways, an analytical framework was produced to guide the analysis (Figure 1). The objective was to describe each of the elements of the framework, as well as the relationships between them, to build an overall picture of the potential mechanisms between provision of interventions and HCV transmission. Secondly, in relation to combining evidence from different study designs, the approach taken here triangulates evidence from ecological and individual-level approaches (described further below). All of the information was collated and summarised in a table, as a means of capturing the evidence for the framework. Unless otherwise indicated, most of this was derived from analysis of the surveys described further below.


Rapid decline in HCV incidence among people who inject drugs associated with national scale-up in coverage of a combination of harm reduction interventions.

Palmateer NE, Taylor A, Goldberg DJ, Munro A, Aitken C, Shepherd SJ, McAllister G, Gunson R, Hutchinson SJ - PLoS ONE (2014)

Analytical framework of potential associations between harm reduction interventions and HCV transmission.The arrows represent investigated associations: relationships A through C are group-level and relationships D through M are individual-level.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128763&req=5

pone-0104515-g001: Analytical framework of potential associations between harm reduction interventions and HCV transmission.The arrows represent investigated associations: relationships A through C are group-level and relationships D through M are individual-level.
Mentions: The difficulties in undertaking what would traditionally be considered ‘robust’ study designs to investigate public health interventions have been well documented [13]–[15]. Nevertheless, some common themes that have emerged from such evaluations, in relation to causal attribution, are (i) the importance of understanding the processes/pathways between intervention(s) and outcome(s) [16] and (ii) the combination of evidence generated from different non-experimental study designs [17]. The analytical approach applied here borrows from these themes: first, to understand pathways, an analytical framework was produced to guide the analysis (Figure 1). The objective was to describe each of the elements of the framework, as well as the relationships between them, to build an overall picture of the potential mechanisms between provision of interventions and HCV transmission. Secondly, in relation to combining evidence from different study designs, the approach taken here triangulates evidence from ecological and individual-level approaches (described further below). All of the information was collated and summarised in a table, as a means of capturing the evidence for the framework. Unless otherwise indicated, most of this was derived from analysis of the surveys described further below.

Bottom Line: We observed a decline in HCV incidence, per 100 person-years, from 13.6 (95% CI: 8.1-20.1) in 2008-09 to 7.3 (3.0-12.9) in 2011-12; a period during which increases in the coverage of OST and IEP, and decreases in the frequency of injecting and sharing of injecting equipment, were observed.Individual-level evidence demonstrated that combined high coverage of needles/syringes and OST were associated with reduced risk of recent HCV in analyses that were unweighted (AOR 0.29, 95%CI 0.11-0.74) and weighted for frequency of injecting (AORw 0.05, 95%CI 0.01-0.18).This is the first study to demonstrate that impressive reductions in HCV incidence can be achieved among PWID over a relatively short time period through high coverage of a combination of interventions.

View Article: PubMed Central - PubMed

Affiliation: Blood-borne Viruses and Sexually Transmitted Infections Section, Health Protection Scotland, Glasgow, United Kingdom.

ABSTRACT

Background: Government policy has precipitated recent changes in the provision of harm reduction interventions - injecting equipment provision (IEP) and opiate substitution therapy (OST) - for people who inject drugs (PWID) in Scotland. We sought to examine the potential impact of these changes on hepatitis C virus (HCV) transmission among PWID.

Methods and findings: We used a framework to triangulate different types of evidence: 'group-level/ecological' and 'individual-level'. Evidence was primarily generated from bio-behavioural cross-sectional surveys of PWID, undertaken during 2008-2012. Individuals in the window period (1-2 months) where the virus is present, but antibodies have not yet been formed, were considered to have recent infection. The survey data were supplemented with service data on the provision of injecting equipment and OST. Ecological analyses examined changes in intervention provision, self-reported intervention uptake, self-reported risk behaviour and HCV incidence; individual-level analyses investigated relationships within the pooled survey data. Nearly 8,000 PWID were recruited in the surveys. We observed a decline in HCV incidence, per 100 person-years, from 13.6 (95% CI: 8.1-20.1) in 2008-09 to 7.3 (3.0-12.9) in 2011-12; a period during which increases in the coverage of OST and IEP, and decreases in the frequency of injecting and sharing of injecting equipment, were observed. Individual-level evidence demonstrated that combined high coverage of needles/syringes and OST were associated with reduced risk of recent HCV in analyses that were unweighted (AOR 0.29, 95%CI 0.11-0.74) and weighted for frequency of injecting (AORw 0.05, 95%CI 0.01-0.18). We estimate the combination of harm reduction interventions may have averted 1400 new HCV infections during 2008-2012.

Conclusions: This is the first study to demonstrate that impressive reductions in HCV incidence can be achieved among PWID over a relatively short time period through high coverage of a combination of interventions.

Show MeSH
Related in: MedlinePlus