Drug use and HIV-1 infection: report from the Second Italian Multicenter Study.

A cross-sectional study was carried out in October 1988 among clients of public health centers in Italy that provide assistance for drug dependency. In addition to estimating the frequency of HIV-1 infection and of risk factors related to drug use, the study estimated the temporal gap between relevant events in the drug history of each subject. Forty-eight centers participated, representing 16 of the 20 Italian regions. Among 1,038/1,348 subjects, 395 (38%) were carriers of HIV-1 antibodies. Seropositivity was related to the length of heroin use (with the risk of being seropositive increasing by 1% for each month of use), to frequency of sharing injection equipment, and to sexual intercourse with a seropositive partner. Women were more likely to have shared injection equipment and to have engaged in sexual intercourse with seropositive partners. Most subjects began sharing injection equipment within a year of initiating drug use, and the median temporal gap between first drug use and first visit to a drug dependency center was 5 years. A high proportion of both seropositive (87%) and seronegative (74%) subjects reported the adoption of safer drug-use practices. In both groups many behavioral changes (38%) were reported to have been introduced before the initial HIV test. These findings confirm that efforts to reduce HIV infection among drug users in Italy will need to concentrate both on prevention of drug use and on early intervention to reduce high-risk behaviors.