Prevalence and correlates of simultaneous, multiple substance injection (co‐injection) amongst people who inject drugs in Melbourne, Australia
【Abstract】
Aims To estimate the prevalence of and risk factors associated with concurrent injection of multiple substances (co‐injection) among a community‐recruited cohort of people who inject drugs. Design Cross‐sectional study. Setting Melbourne, Australia. Participants A sample of 720 actively injecting participants from the Melbourne Injecting Drug User Cohort Study (33% female) was extracted. Measurements We constructed two statistical models: a logistic regression model analysing correlates of co‐injection of any substance combination in the past month and a multinomial logistic regression model analysing correlates of three mutually exclusive groups: heroin‐diphenhydramine co‐injection only, co‐injection of other substances and no co‐injection. Risk factors examined included drug use characteristics, demographic characteristics, health service use, hepatitis C status, injection risk behaviours and previous experience of non‐fatal overdose. Findings One‐third (n=226, 31%; 95% CI: 28‐34%) of participants reported co‐injecting substances within the past month, with equal numbers of participants reporting injecting combinations of heroin‐diphenhydramine (n=121, 54%; 95% CI: 48‐60%) and heroin‐methamphetamine (n=121, 54%; 95% CI: 48‐60%). In logistic regression analyses, reporting co‐injection of any substance combination was associated with male sex (AOR: 1.80, 95% CI: 1.18‐2.74, p=0.006) and injecting daily or more frequently (AOR: 2.04, 95% CI: 1.31‐3.18, p=0.002). In multinomial logistic regression analyses, participants reporting heroin‐diphenhydramine co‐injection only were significantly more likely to report groin injecting (ARRR: 6.16, 95% CI: 2.80‐13.56, p<0.001) and overdose (requiring an ambulance) in the past 12 months (ARRR: 2.81, 95% CI: 1.17‐6.72, p=0.021) compared with participants reporting no co‐injection or co‐injection of other substances. Conclusions A substantial proportion of people who inject drugs report co‐injection of multiple substances, which is associated with a range of socio‐demographic, drug use and health service use risk factors.
【Author】
Anna Palmer, Peter Higgs, Nick Scott, Paul Agius, Lisa Maher, Paul Dietze
【Journal】
Addiction(IF：6.9) Time：2020-08-09
