Few data have been available to examine the longitudinal behavioral changes among injection drug users despite the favorable findings of previous studies on reduced risk in drug injection and needle sharing. A substantial number of injection drug users may either not change their risk behaviors or may lapse later. This study examined the longitudinal risk patterns of drug injection and patterns of unprotected sexual practice over a 48-month follow-up period. The main purpose of this paper was to develop predictive models of initiation and maintenance of safer behaviors and, in particular, to identify factors that predict the maintenance or initiation of safer behavior over time. Four patterns of behavioral changes for both drug injection and sexual practice were defined: Initiation of safer behaviors, consistently unsafe practices, lapse into risky practices, and maintenance of risk reductions. A total of 415 injection drug users participated in the Risk Assessment Project in Philadelphia. All participants were assessed every six months using the Risk Assessment Battery and HIV antibody test. Each participant had at least two observation points. Using the logit model with generalized estimating equations method, the author found the following results. The longitudinal patterns of risky sexual practice was significantly associated with the patterns of drug injection. Being Black and unemployed at baseline were significant predictors of initiation of cessation of drug injection. Being Black, being in methadone treatment, and receiving the HIV seropositive result were significant predictors of maintenance of cessation of drug injection. Being female and receiving the HIV seropositive result were significant predictors of initiation of safer sexual practice. Being older, being female, and receiving the HIV seropositive result were significant predictors of maintenance of safer sexual practice. Implications for further interventions are discussed.
