Objective: To determine the prevalence of the major risk behavior in HIV transmission (syringe sharing and failure to use condoms) and associated factors among drug injectors recruited for a syringe exchange program (PIJ) in the city of Madrid.
Methods: Cross-section study. All the information was obtained in 1993 through structured interviews with 441 users who had injected drugs during the previous month and had resorted to the PIJ five times, at most. The reference period for drug use and risk behaviour was the month prior to the interview. The statistical analysis included bivariate methods and logistical regression techniques.
Results: 29.2% shared syringes (18% passing and 21.7% taking used syringes) and of those that had sexual intercourse (49.4%), 42.5% always used a condom. 89.5% had an HIV antibody test and of those that knew the results, 48.6% were HIV-positive. Multivariate analysis showed that the association between certain behaviour patterns was significant; i.e., taking used syringes and: passing used syringes (odds ratio -OR- = 6.1; 95% confidence interval -CI- = 3.0-12.5), being HIV-positive (OR = 4.1; CI = 1.8-9.1), being unaware of HIV antibody test status (OR = 4.2; CI = 1.7-10.2) and having used intravenous drugs for 5-9 years (OR = 2.9; CI = 1.1-7.9); the association was significant between passing used syringes and: using a mixture of heroin and cocaine (OR = 2.7; CI = 1.1-6.4) and being unaware of HIV antibody test status (OR = 2.5; CI = 1.1-6.0). In the sample as a whole, the association between not using condoms ever and consuming cocaine (OR = 1.7; CI = 1.1-2.9) or crack (OR = 3.0; CI = 1.5-5.9) was significant; furthermore, among those that had sexual intercourse, the association was significant between not using condoms ever and: having been in jail (OR = 2.9; CI = 1.3-6.4), injecting drugs 2-4 times a day (OR = 2.4; CI = 1.0-5.8), having sexual intercourse with drug injectors (OR = 2.6; CI = 1.2-5.9) and having intercourse with two or more partners (OR = 0.4; CI = 0.2-0.9).
Conclusions: The prevalence of HIV infection and risk behavior in the transmission of this virus remain high among drug injectors in Madrid. The habit of sharing syringes is still common, especially among HIV-positive drug injectors (a high percentage take used syringe) and among those who are unaware of their HIV antibody test status. The use of condoms is less frequent among those who have sexual intercourse with other drug injectors or with only one partner.