The prevalence and incidence of HIV among injection drug users: A five year panel study

Six hundred and one injection drug users (IDUs) who attended drug treatment programs in Miami, Florida, were enrolled in a panel study to determine th e prevalence and incidence of human immunodeficiency vints (HIV) and associ ated risk factors. A structured questionnaire which elicited injection and sexual behaviors was administered and blood was obtained by venipduncture. All participants were reassessed at six month intervals for 5 years. The ba seline prevalence of HIV was 16.3%. African-Americans had a prevalence of H IV (37.1%) that was significantly higher than that of non-Hispanic whites ( 7.6%); the prevalence of HIV among Hispanics was 27.2%. Persons who were mo re than thirty years of age were more likely to test HIV positive (17.8%) t han were younger participants (9.7%). The annual incidence per 1000 person- years of exposure for the 503 initially seronegative participants was consi stently low for each year of the study. The 5 year incidence was 4.1 per 10 00 person years; 7.5 for men and 1.7 for women, 7.5 for African-Americans a nd 3.8 for non-Hispanic whites. No Hispanic participants seroconverted. Mul tivariate logistic techniques were used to identify the independent risk fa ctors for HIV prevalence. Earlier injection, ethnicity, and income were ind ependently associated with HIV serostatus. A history of a sexually transmit ted disease was marginally associated with HIV prevalence. Low incidence pr obably is a function of the reduction of risk behavior that occurred over t he course of the study and the stage of the epidemic.