TY - JOUR
T1 - Modelling the impact of a national scale-up of interventions on hepatitis C virus transmission among people who inject drugs in Scotland
AU - Fraser, H.
AU - Mukandavire, C.
AU - Martin, N.K.
AU - Goldberg, D.
AU - Palmateer, N.
AU - Munro, A.
AU - Taylor, A.
AU - Hickman, M.
AU - Hutchinson, S.
AU - Vickerman, P.
N1 - Acceptance in SAN
AAM: 12m embargo
PY - 2018/11
Y1 - 2018/11
N2 - Background and Aims: To reduce hepatitis C virus (HCV) transmission among people who inject drugs (PWID), Scottish Government-funded national strategies, launched in 2008, promoted scaling-up opioid substitution therapy (OST) and needle and syringe provision (NSP), with some increases in HCV treatment. We test whether observed decreases in HCV incidence post-2008 can be attributed to this intervention scale-up. Design: A dynamic HCV transmission model among PWID incorporating intervention scale-up and observed decreases in behavioural risk, calibrated to Scottish HCV prevalence and incidence data for 2008/09. Setting: Scotland, UK. Participants: PWID. Measurements: Model projections from 2008 to 2015 were compared with data to test whether they were consistent with observed decreases in HCV incidence among PWID while incorporating the observed intervention scale-up, and to determine the impact of scaling-up interventions on incidence. Findings: Without fitting to epidemiological data post-2008/09, the model incorporating observed intervention scale-up agreed with observed decreases in HCV incidence among PWID between 2008 and 2015, suggesting that HCV incidence decreased by 61.3% [95% credibility interval (CrI) = 45.1–75.3%] from 14.2/100 person-years (py) (9.0–20.7) to 5.5/100 py (2.9–9.2). On average, each model fit lay within 84% (10.1/12) of the confidence bounds for the 12 incidence data points against which the model was compared. We estimate that scale-up of interventions (OST + NSP + HCV treatment) and decreases in high-risk behaviour from 2008 to 2015 resulted in a 33.9% (23.8–44.6%) decrease in incidence, with the remainder [27.4% (17.6–37.0%)] explained by historical changes in OST + NSP coverage and risk pre-2008. Projections suggest that scaling-up of all interventions post-2008 averted 1492 (657–2646) infections over 7 years, with 1016 (308–1996), 404 (150–836) and 72 (27–137) due to scale-up of OST + NSP, decreases in high-risk behaviour and HCV treatment, respectively. Conclusions: Most of the decline in hepatitis C virus (HCV) incidence in Scotland between 2008 and 2015 appears to be attributable to intervention scale-up (opioid substitution therapy and needle and syringe provision) due to government strategies on HCV and drugs.
AB - Background and Aims: To reduce hepatitis C virus (HCV) transmission among people who inject drugs (PWID), Scottish Government-funded national strategies, launched in 2008, promoted scaling-up opioid substitution therapy (OST) and needle and syringe provision (NSP), with some increases in HCV treatment. We test whether observed decreases in HCV incidence post-2008 can be attributed to this intervention scale-up. Design: A dynamic HCV transmission model among PWID incorporating intervention scale-up and observed decreases in behavioural risk, calibrated to Scottish HCV prevalence and incidence data for 2008/09. Setting: Scotland, UK. Participants: PWID. Measurements: Model projections from 2008 to 2015 were compared with data to test whether they were consistent with observed decreases in HCV incidence among PWID while incorporating the observed intervention scale-up, and to determine the impact of scaling-up interventions on incidence. Findings: Without fitting to epidemiological data post-2008/09, the model incorporating observed intervention scale-up agreed with observed decreases in HCV incidence among PWID between 2008 and 2015, suggesting that HCV incidence decreased by 61.3% [95% credibility interval (CrI) = 45.1–75.3%] from 14.2/100 person-years (py) (9.0–20.7) to 5.5/100 py (2.9–9.2). On average, each model fit lay within 84% (10.1/12) of the confidence bounds for the 12 incidence data points against which the model was compared. We estimate that scale-up of interventions (OST + NSP + HCV treatment) and decreases in high-risk behaviour from 2008 to 2015 resulted in a 33.9% (23.8–44.6%) decrease in incidence, with the remainder [27.4% (17.6–37.0%)] explained by historical changes in OST + NSP coverage and risk pre-2008. Projections suggest that scaling-up of all interventions post-2008 averted 1492 (657–2646) infections over 7 years, with 1016 (308–1996), 404 (150–836) and 72 (27–137) due to scale-up of OST + NSP, decreases in high-risk behaviour and HCV treatment, respectively. Conclusions: Most of the decline in hepatitis C virus (HCV) incidence in Scotland between 2008 and 2015 appears to be attributable to intervention scale-up (opioid substitution therapy and needle and syringe provision) due to government strategies on HCV and drugs.
KW - hepatitis C
KW - virus transmission
KW - injecting drug users
KW - Scotland
U2 - 10.1111/add.14267
DO - 10.1111/add.14267
M3 - Article
C2 - 29781207
VL - 113
SP - 2118
EP - 2131
JO - Addiction
JF - Addiction
SN - 0965-2140
IS - 11
ER -