Factors Associated with Undiagnosed Hepatitis C Infection among People who Inject Drugs: Missed Opportunities for Diagnostic Testing in The United Kingdom (UK)

Author: VD Hope, KJ Cullen, JV Parry, F Ncube

Theme: Epidemiology & Public Health Research Year: 2015

People who inject drugs (PWID) typically have high levels of hepatitis C virus (HCV) infection. Most will develop chronic infection with a risk of cirrhosis and liver cancer. The development of very effective antivirals means that diagnosis is increasingly important to reducing HCV morbidity. Factors associated with undiagnosed HCV among PWID are examined to identify opportunities for improving diagnosis and so treatment access.

A voluntary unlinked-anonymous survey obtained dried-blood spot samples and questionnaires from PWID across the UK (except Scotland). Factors associated with diagnosis were explored among the HCV antibody (anti-HCV) positive participants, by comparing those with undiagnosed and diagnosed HCV (self-reported diagnoses).

During 2013, 934 anti-HCV positive participants had injected during the preceding year (mean age 37 years; 26% women; 7% not UK born). During the preceding year, 91% injected heroin, 53% crack, 29% amphetamine, and 16% had receptively shared needles/syringes. Overall, 53% were unaware of their HCV status; 12% had never had a diagnostic test. In multivariable analyses, being aware of HCV status was associated with: older age (mean 39 vs. 36 years; adjusted odds ratio [AOR] per year increase 1.05, 95%CI 1.03-1.07); not being UK born (56% aware vs. 46%; AOR=1.80, 95%CI 1.08-2.99); receptive sharing (55% vs. 45%; AOR=1.56, 95%CI 1.08-2.25); and injecting crack (51% vs. 41%; AOR=1.48, 95%CI 1.13-1.92). Of those unaware, 84% were using needle/syringe programmes and 68% were in addiction treatment; other services recently used were general practitioners (61%), emergency departments (29%), minor-injury clinics (18%), and genitourinary medicine (9%).

Younger PWID, those UK born, those not injecting crack or sharing were more likely to have undiagnosed HCV infection. Those with undiagnosed HCV made extensive use of specialist services and primary care. These findings indicate settings and groups where the offer and/or the acceptance of HCV testing needs to be improved.

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