Factors associated with the development of systemic versus local infections in people who inject drugs

To describe bacterial infections among people who inject drugs (PWID) in France, identify factors associated with systemic infection and define patient groups based on demographic and consumption profiles.

National, cross-sectional, multicenter study using spontaneous reports collected by the French Addictovigilance Network from January 2019 to December 2024. Local and systemic infections were compared to identify associated sociodemographic and injection-related factors. These variables were used to build patient profiles through hierarchical clustering approach.

A total of 727 bacterial infections were analyzed (56% local and 44% systemic) in mainly men (79%), with a median age of 39 years. The most common infections were soft skin and tissue infections (65%), abscesses (51%), endocarditis (20%) and sepsis (15%). Cocaine (46.5%), heroin (16.5%) and buprenorphine (16.6%) were the main injected substances. Injecting stimulants only was associated with lower odds of systemic infection when compared to injecting a stimulants/opioids combination (OR 0.61 [95%CI: 0.40-0.93]) while older age (OR 1.02 [95%CI: 1.01-1.04]) and HIV-negative individuals not engaging in slam (OR 3.62 [95%CI: 1.46-8.98]) were associated with systemic infection compared to HIV-negative individuals engaging in slam. Five clusters were identified: I- Male, single substance injectors, opioids or stimulant, II- Female, single substance injectors, opioids or stimulant, III- Both opioids and stimulants injectors, IV- Young PWID, injectors of single substances outside opioids/stimulants presenting local infections, V- HIV-positive men, engaging in slam, having local infections.

Our findings illustrate how the type of psychoactive substances and the sociodemographic profile are related to the infection type among PWID.