Human immunodeficiency virus infection and other risk factors for skin abscesses and endocarditis among injection drug users

Objective: to study incidence rates of and risk factors for skin abscesses at the site of injection and episodes of endocarditis among injection drug users (IDU). Design: A comprehensive, open cohort study of drug users on the natural history of human immunodeficiency virus (HIV) infection. Methods: From 1986 to 1994, injection drug users in Amsterdam were included in the study. Incidence rates of self-reported skin abscesses and verified episodes of endocarditis were calculated, In uni- and multivariate Poisson regression analysis, risk factors for skin abscesses and endocarditis were determined. Results: 521 HIV-seronegative and 237 HIV-seropositive IDU were followed for 1640 person-years, A total of 545 skin abscesses were reported by 269 IDU (incidence 33/100 person-years). HIV infection, female gender, prostitution among females, foreign nationality, injection of heroin and cocaine, a high frequency of injecting, and obtaining syringes through the needle exchange program were independently and positively associated with skin abscesses. During follow-up, 17 verified episodes of endocarditis were observed (incidence 1.3/100 person-years). Endocarditis was independently associated with HIV infection and a previous history of endocarditis. Furthermore, women and IDU with a skin abscess appeared to be at an increased risk for endocarditis. Conclusions: HIV infection is an independent risk factor for skin abscesses and endocarditis. Also, women are at an increased risk for these injection related infections. Prevention activities, like promotion of skin cleaning, should be directed at those IDU in whom one or more risk factors have been identified.