P1-S2.26 Drug and sexual HIV risk among injection drug users - a latent class analysis

Abstract

Background: Injection drug users (IDUs) are at increased risk of HIV infection because they are more likely to engage in high risk injection behaviours (eg, needle sharing) as well as in high risk sexual behaviours (eg, exchange sex). This analysis examines factors associated with HIV risk using a latent class approach. Methods: Our study includes 523 eligible injection drug users, recruited into the 2009 National HIV Behavioural Surveillance project. Using maximum likelihood we calculated the posterior probability of being in an HIV risk class from nine drug and sexual behaviours.We simultaneously fitted a multinomial regression model to identify socio-demographic factors associated with HIV risk class. Results: We identified 3 HIV risk classes-high (42%), moderate (25%) and low risk (33%). Compared to the high HIV risk class, homeless IDUs had lower odds to be in the moderate (OR=0.16, 95% CI 0.04 to 0.70) and in low risk HIV class (OR=0.28, 95% CI 0.15 to 0.52). Moreover, IDUs who were arrested in the past 12 month had also lower odds to be in low risk class (OR=0.52, 95% CI 0.32 to 0.86) compared to high HIV risk class. Conclusions: Our results show that the majority of our IDUs were engaged in high HIV risk behaviours. Though temporality cannot be established due to the cross-sectional study design our findings indicate that homelessness and history of incarceration are associated with HIV risk. Interventions targeting system-level change may help to reduce the burden of HIVamong the injection drug user population.