Recurring Severe Injection-related Infections in People Who Inject Drugs and the Need for Safe Injection Sites in Spain

Background and aims: An estimated 68,297 people with opioid use disorder engage in opioid agonist therapy (OAT) in Spain. We aimed to calculate the incidence of severe injection-related infections in people who inject drugs (PWID) engaged in OAT in a harm reduction setting without a safe injection site (SCS).Methods: A retrospective cohort study was performed in PWID engaged in OAT and in a mobile harm reduction unit to identify who was admitted to a referral hospital for any severe injection-related infections between 1 Jan 2016 and 31 Dec 2019. A Cox proportional hazard regression analysis was used to assess factors associated with any severe injection-related infection.Results: 237 PWID engaged in OAT were included. After a median follow-up of 5.5 months (IQR 1.3–22.7), a total of 104 episodes of severe injection-related infections occurred in 56 individuals, and admission for a second event occurred in 35.7% of this same group. The incidence density of any type of severe injection-related infection was 26.8 (20.2–34.8) episodes per 100 PY, and the incidence density of complicated skin and soft tissue infections (SSTIs) that required hospital admission was 20.4 (15.0–27.3) episodes per 100 PY. Fifty-six (53.8%) of all the episodes were patient-directed discharge (PDD), and people who had two or more hospital admissions had a higher PDD frequency.Conclusion: Severe injection-related infections remain highly prevalent among PWID cared for in a harm reduction setting without a SCS. PDD were more frequent in higher-risk individuals who presented two or more hospital readmissions.