Full participation in harm reduction programmes is associated with decreased risk for human immunodeficiency virus and hepatitis C virus: evidence from the Amsterdam Cohort Studies among drug users

TLDR

To assess how harm‑reduction programmes affect HIV and hepatitis C virus incidence among ever‑injecting drug users in the Amsterdam Cohort Studies. Using Poisson regression on 714 participants, the study evaluated the association between combined methadone dose and needle exchange participation across five categories, from no participation to full participation (≥60 mg methadone/day with or without current injecting and all needles exchanged). Full participation in a harm‑reduction programme was linked to a significantly lower risk of HIV and HCV seroconversion (IRR 0.43 for HIV, 0.36 for HCV), whereas methadone or needle exchange alone showed no significant effect.

Abstract

ABSTRACT Objectives To investigate the impact of harm‐reduction programmes on HIV and hepatitis C virus (HCV) incidence among ever‐injecting drug users (DU) from the Amsterdam Cohort Studies (ACS). Methods The association between use of harm reduction and seroconversion for human immunodeficiency virus (HIV) and/or hepatitis C virus (HCV) was evaluated using Poisson regression. A total of 714 DU were at risk for HIV and/or HCV during follow‐up. Harm reduction was measured by combining its two most important components—methadone dose and needle exchange programme (NEP) use—and looking at five categories of participation, ranging from no participation (no methadone in the past 6 months, injecting drug use in the past 6 months and no use of NEP) to full participation (≥ 60 mg methadone/day and no current injecting or ≥ 60 mg methadone/day and current injecting but all needles exchanged). Results Methadone dose or NEP use alone were not associated significantly with HIV or HCV seroconversion. However, with combination of these variables and after correction for possibly confounding variables, we found that full participation in a harm reduction programme (HRP) was associated with a lower risk of HIV and HCV infection in ever‐injecting drug users (DU), compared to no participation [incidence rate ratio 0.43 (95% CI 0.21–0.87) and 0.36 (95% CI 0.13–1.03), respectively]. Conclusions In conclusion, we found that full participation in HRP was associated with a lower incidence of HCV and HIV infection in ever‐injecting DU, indicating that combined prevention measures—but not the use of NEP or methadone alone—might contribute to the reduction of the spread of these infections.