Increased risk of HIV and other drug-related harms associated with injecting in public places among people who inject drugs in Scotland: a national bio-behavioural survey

Abstract

BackgroundAlthough public injecting is considered a proxy for high-risk behaviour among people who inject drugs (PWID), studies quantifying its relationship with multiple drug-related harms are lacking. Furthermore, none have hitherto examined this issue in the context of an HIV outbreak, which has been ongoing in Glasgow, Scotland since 2015. We aimed to estimate the prevalence of public injecting in Scotland and associated risk factors; and estimate the association between public injecting and HIV, active HCV, overdose, and skin and soft tissue infections (SSTI). MethodsA cross-sectional, bio-behavioural survey (including dried-blood spot testing to determine HIV and HCV) of PWID recruited by independent interviewers from 139 harm reduction services across Scotland was done between July 7, 2017, and Oct 1, 2018. Participants were eligible if they had a history of injecting drug use. Only current PWID (ie, in the past 6 months) were included in the analysis. Primary outcomes were injecting in a public place (yes or no; used both as outcome and exposure); HIV infection; active HCV infection; self-reported overdose in the past year (yes or no), and SSTI the past year (yes or no). Multivariable logistic regression was used to determine factors associated with public injecting and to estimate the association between public injecting and related harms (HIV, active HCV, overdose, and SSTI). Findings1469 eligible PWID were included in the study. Prevalence of public injecting among PWID was 16% [95% CI 15–18] overall in Scotland and 47% [40–53] in Glasgow city centre. Factors associated with public injecting were recruitment in Glasgow city centre (adjusted odds ratio 5·45 [95% CI 3·48–8·54], p<0·0001), homelessness (3·68 [2·61–5·19], p<0·0001), high alcohol consumption (2·42 [1·69–3·44], p<0·0001), high daily injection frequency (3·16 [1·93–5·18], p<0·0001), and cocaine injecting (1·46 [1·00–2·13], p=0·046). Odds were lower for those receiving opiate substitution therapy (0·37 [0·24–0·56], p<0·0001) and older age (per year increase; 0·97 [0·95–0·99], p=0·013). Public injecting was associated with an increased risk of HIV (2·11 [1·13–3·92], p=0·019), active HCV (1·49 [1·01–2·19], p=0·043), overdose (1·59 [1·27–2·01], p<0·0001), and SSTI (1·42 [1·17–1·73], p=0·00046). InterpretationIn the context of UK policy debates about the provision of safer drug consumption facilities, these findings highlight the need to address the additional harms evident among people injecting in public places. FundingHealth Protection Scotland.