Melbourne Injecting Drug User Cohort Study (MICS)

Expected Date of Completion:
Drug Type:
image - Syringe Updated
Project Main Description

People who inject drugs (PWID) are exposed to blood-borne virus (BBV) infections, injecting-related injuries and risk of overdose, and experience greater levels of both physical and mental impairment compared with the general population.

Additionally, injecting drug use is associated with a range of social and economic harms.

The ability to respond to the significant morbidity and mortality associated with injecting drug use is limited by a lack of understanding of the complex ways in which drug-related harms are produced, and the ways in which interventional efforts can be optimised.

Most Australian and much international research among this population has been cross-sectional; there is a clear need for longitudinal data on injecting drug use, particularly with out-of-treatment drug users.


This study uses a mix of objective and self-report data to:

  1. examine typical trajectories of injecting drug use in Australia and determine risk and protective factors for users in the health, social and psychological domains.
  2. establish a framework for the evaluation of interventions with people who inject drugs (PWID) across a variety of health and social outcomes.
  3. compare the effects of methamphetamine injection with the effects of heroin injection.
Design and Method

This is a prospective cohort study of PWID. In Melbourne, baseline interviews on demographics, drug use history and market access patterns, treatment history, criminal involvement, and current psychological, social and health states were conducted with 688 people who inject drugs over the period November 2008 – November January 2010. Information and consent collected at baseline allows linkage to a variety of objective datasets such as the National Death Index and Ambulance Victoria’s ADIS system. These linkages will provide objective information on harms associated with injecting drug use over time. We are also conducting direct follow-up of the established cohort to determine changes from baseline over time. Follow-up interviews commenced in late 2009 and have been progressing well using modified versions of the baseline questionnaire. The particular focus is upon determining changes in drug preferences (including drivers for these changes), treatment utilisation and experience, periods of abstinence, experience of harm and the identification of risk and protective factors for these outcomes, including service utilisation and drug use patterns. The study is using protocols for locating study participants successfully developed and implemented in other Australian studies of IDU. We will also be able to determine the effects of any interventions or services to which the participants are exposed by comparing those cohort members exposed to the intervention to those who have not been so exposed.


Using a variety of recruitment methods including street outreach and respondent driven sampling (RDS), 688 young heroin and methamphetamine injectors have been recruited into the study.

At baseline, the median age of participants was 27.6 years and two thirds were male.

The majority of participants reported recent heroin injection, and one third reported being enrolled in Opioid Substitution Therapy (OST) at recruitment.

The first series of annual follow-up interviews has been completed with 458 participants (71 percent of eligible participants) retained in the study. The second and third rounds of annual follow-up interviews are underway.

A number of journal articles related to MIX baseline data have been submitted for publication in peer-reviewed journals.


Aitken, C., Kerr, T., Hickman, M., Stoove, M., Higgs, P., & Dietze, P. (2012). A cross-sectional study of emergency department visits by people who inject drugs. Emergency Medical Journal, doi:10.1136/emermed-2012-201170

Project Collaborators: External

Paul Dietze

Campbell Aitken

Mark Stoove

Danielle Horyniak

Peter Higgs

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Date Commenced

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