SEROCONVERSION ISSUES AMONG OUT-OF-TREATMENT INJECTION-DRUG USERS

Many risk factors for HIV incidence among drug users have been reporte d in the literature. However most of these studies have been with foca l samples, and typically have had limited sample sizes. The National I nstitute on Drug Abuse (NIDA) funded a Cooperative Agreement for AIDS Community-Based Outreach/Intervention Research (CA) since 1991 that pr oduced a national database. Associations found in the literature were tested to determine whether they were replicated on this national data base. The CA national database had complete data, including blood draw s six months apart, on 6,970 drug users who were seronegative at basel ine. Sites that had no seroincident cases were excluded from the analy sis. Twenty-nine risk factors identified in the literature were tested on the national database on a bivariate basis. There were 56 seroinci dent cases (those who were HIV-seronegative at baseline and HIV-seropo sitive at follow-up) out of 3752 person years at risk, for a seroconve rsion rate of 1.49 (CI 1.05, 1.94) per 100 person years at risk. Data were analyzed both as a whole dataset and with the sites stratified by high and low prevalence. In the overall analysis, risk factors associ ated with seroconversion were times injected any drug, ever injected a ny drug, days injected cocaine, times injected cocaine, and times inje cted speedball (these variables had a 30-day time referent). Also sign ificant was how recently formerly-used injection equipment was used. H igh-prevalence sites revealed associations for times injected any drug , days injected cocaine, and times injected speedball. Low-prevalence sites revealed associations for injected any drug and days injected co caine. These findings highlight the importance of injection drug use, especially cocaine injection, as a major risk factor in recent serocon version.