An Investigation into predictors of risk-associated injecting behaviours in a sample of injecting drug users

LITERATURE REVIEW The sharing and lending of injecting equipment amongst the injecting drug user (IDU) population has been identified as a leading cause of the transmission of blood-borne viruses such as hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV). A large body of research exists which has attempted to identify those IDU who are at elevated risk for engaging in behaviours known to be associated with BBV transmission. Primary amongst these identified factors are those relating to impulsivity traits, psychological distress including anxiety and depression, and pharmacological effects of drug use. Also, a number of demographic and drug use variables also are routinely investigated in the literatures as possible risk factors, and typically include factors of sex, age, duration of injecting history, frequency of injecting, preferred drug of choice, sexual orientation, drug treatment status, accommodation status, education level, ethnicity, and the presence or absence of prison history. The following literature review describes the existing research into each of these key variables, elucidating those which present as the clear risk factors for BBV transmission risk behaviours, and those which are somewhat ambivalent in the prediction of risk behaviours and BBV transmission rates. Further, the review discusses the need for comprehensive research to be conducted, identifying the variables that are most predictive of BBV risk behaviours amongst this population. EMPIRICAL STUDY Incidence of blood-borne viruses such as Hepatitis B, Hepatitis C, and HIV have begun to rise in recent years, with Hepatitis C now being the most communicable disease in Australia. Spread by blood-to-blood contact, it is now recognised that by far the majority of new cases of blood-borne viruses are transmitted during the process of injecting illicit drugs, through behaviours such as the sharing of injecting equipment. Previous studies have identified a number of factors that independently predict the risk of injecting drug users (rpm engaging in these risk behaviours. These factors include demographic, drug use and injection variables, psychological distress factors (i.e. anxiety and depression), and impulsivity factors, however to date no research has comprehensively examined these risk factors in a combined sense in order to establish which IDU are at a heightened risk for engaging in risky injection episodes. The current study sought to address this, and utilised a multivariate regression modelling approach with a sample of 269 regular IDU in Tasmania to examine the contribution of the above factors to the prediction of the engagement in various injecting risk behaviours. The study details factors which emerged as significant predictors to transmission through needle and syringe contamination, other equipment contamination, contamination from injecting others, exposure from being injected by others, needlestick contamination, as well as overall risk. While the factors which significantly contribute to risk in the various aspects of transmission behaviours vary, the factors of unstable accommodation status, amphetamine use, alcohol use, less occasions of self-injection, higher symptoms of anxiety, and a desire to seek out novel stimulation emerged as the most significant contributors to overall risk. Of these, elevated anxiety symptoms and reduced episodes of self-injection were clearly the most important factors as identified in a multivariate model for overall risk of engaging in blood-borne virus risk behaviours. This finding suggests that while there is value in delivering blood-borne virus transmission intervention efforts to all IDU, particular attention and emphasis should be paid to those IDU exhibiting the above risk factors. Specific strategies for intervention is discussed in the below report.