[Factors associated with sharing syringes among street-recruited injecting drug users]

To estimate the prevalence of risk behaviors related to drug use and to identify factors associated with of accepting and passing on used syringes among intravenous drug users (IDU) recruited in Barcelona city and other surrounding areas in 2004.

A cross-sectional study of IDU recruited from the streets by ex-IDU interviewers. A standardized and anonymous questionnaire which explored behaviors in the previous 6 months was used. Saliva samples were collected to determine human immunodeficiency virus (HIV) prevalence. Logistic regression models were used to identify determinants of accepting and passing on used syringes.

Of the 300 participants, 17.7% and 13.3% accepted and passed on used syringes, respectively. 74.8% practiced front-backloading (to prepare the drug solution in a syringe and then divide it up into other syringes) and 77.9% shared other equipment. The prevalence of HIV was 57.7%. The predictors of accepting used syringes were using more than 4 drugs (odds ratio [OR] = 5.6), having a positive hepatitis C virus status (OR = 7.3), practising front/backloading (OR = 12.6) and having an IDU steady partner (OR = 2.9); and with passing on used syringes were practicing front/backloading (OR = 4.9), having an IDU steady partner (OR = 5.8), and having sexual risk behaviors with casual partners (OR = 4.0). Starting to inject drugs older than 15 years of age was a protective factor (OR = 0.2).

The prevalence of risk behaviors related to drug use remains high, especially indirect sharing, just as the prevalence of HIV and hepatitis C virus. Prevention programs should be targeted to IDU, especially to young IDU, polydrug users and those who have an IDU steady partner.