This prospective cohort study recruited incarcerated males nearing the end of their sentences who had a self-reported history of regular IDU in the months immediately prior to incarceration. Data collection consisted of in-depth quantitative interviews, blood specimen collection and blood-borne virus testing, and record linkage to health, housing and justice databases. Primary data collection for the study included extensive quantitative interviews conducted at baseline (pre-release) and 3, 12 and 24 months after release, which constitute the primary study data. Blood specimen collection occurred at baseline, 12 months and 24 months. Data linkage is planned at 2, 5 and 10 years post-release to describe long-term service interactions and health, social and criminal justice outcomes. This paper describes the sample on the basis of their responses to baseline interviews which were conducted in prison.
Between September 2014 and June 2016, participants were recruited from three male prisons in the Australian state of Victoria. Operational limitations in the state’s women’s prisons at the time of data collection prevented planned recruitment of female participants. Recruitment prisons were selected to enhance sample heterogeneity by geography (metropolitan, regional) and security level (minimum, medium, maximum security). Recruitment targets at each prison aimed to reflect a proportional representation of the prison population size at each site. The male prisoner population in Victoria in 2016 was estimated at 6,644  and the minimum, medium and maximum security recruitment prisons accommodated an estimated 242, 552 and 1067 prisoners, respectively .
Individuals were eligible to participate if they self-reported injecting drugs at least once a month in the 6 months before incarceration, were being aged 18 years or over,Footnote 1 were a sentenced prisoner (i.e. not on remand), consented to participate in four face-to-face interviews (in-prison baseline and three follow-up interviews in the community), provide blood specimens, be regularly contacted by researchers over the follow-up period and record linkage for 10 years following recruitment.
Baseline interviews were scheduled for within 12 weeks of participants’ expected release dates, which were determined using a combination of recorded end-of-sentence dates and prisoner self-report of anticipated early release on parole, validated by prison staff at the time of recruitment. When release was delayed 12 weeks beyond baseline interviews, short catch-up interviews were conducted to update time-variant pre-release data.
Recruitment and Consent
Recruitment criteria of recent pre-incarceration IDU prevented random sampling using prison administrative records. To recruit participants, researchers engaged directly with prisoners at medical centres during dosing times for opioid substitution therapy (OST), at alcohol and other drugs (AOD) therapeutic group sessions, through prison workplaces and in prison units/cell blocks. Researchers engaged peer representatives and staff involved in program delivery to prisoners with IDU histories to promote the study and presented at ‘town hall meetings’ (regular meetings of prisoners and staff), educational programs and prison workplaces. Study posters were displayed in general access areas of prisons. Those interested in participating who were not engaged directly by researchers completed ‘expression of interest’ forms, which they could submit directly to researchers, clinical or program staff, or place in secure mailboxes in prisons. These forms helped protect confidentiality and provided consent for researchers to contact prisoners and discuss the study in accordance with prison operations and ethics committee protocols. Researchers screened potential participants for eligibility, and once eligibility was established, a baseline interview was scheduled.
During the informed consent process, researchers verbally reinforced key elements of the written participant information and consent forms. The concept and process of record linkage, including participant confidentiality, and types of information sought from data custodians, was discussed with participants. In accordance with government requirements, participants completed a separate form to consent to data linkage to their federal medical records. Pre and post-test discussions occurred with all participants when baseline blood samples were collected, with test results delivery scheduled following release.
Baseline Data Collection
Researchers used electronic tablets to administer quantitative questionnaires, and data were downloaded into an electronic database (Mobile Data Studio Software) . Questionnaires covered six domains: socio-demographics, social support, physical health, mental health, alcohol and other drug use and related behaviours, and pre-release and transitional services and arrangements. Items were adapted from those used in a cohort study of community-recruited PWID  and tested in a pilot study , alongside standardised and validated scales (Table 1). Mean duration of interviews was 45 min (SD = 12 min, range 26–73 min).
A dry blood spot finger-prick blood specimen was collected for hepatitis C antibody testing using commercially available assays. HIV testing was not performed due to the low prevalence of HIV among Victorian prison populations . Hepatitis B testing was not performed due to budget limitations and the cost of dry blood spot assays.
Contact-tracing details were collected on paper-based forms and stored in an electronic database separate to survey data. To facilitate follow-up, researchers collected detailed participant identifying information (full name, date of birth, alias/street name, expected residential address, expected telephone numbers after release) and secondary contact details for friends, relatives, services or specific workers they anticipated contacting after release.
Participants were not reimbursed for baseline interviews in prison in accordance with the Corrections Victoria guidelines.
Follow-up Data Collection
Researchers are conducting follow-up interviews at 3, 12 and 24 months after release from prison (3- and 12-month interviews complete at time of writing) and collecting venous blood samples for hepatitis B and hepatitis C antibody and virus testing (including RNA tests to determine chronic/active infections) at 12 and 24 months. Researchers provide blood test results to participants where possible and offer referral to hepatitis care and treatment providers.
Follow-up questionnaires are adapted from those administered at baseline, removing time-invariant items and adding or adapting items to capture prospectively occurring events and to reflect differences between the community and prison environments. Participants receive AUD40 as a cash payment for each follow-up interview completed in the community.
Researcher contact with participants during follow-up occurs via regular phone, email and social media contact, or via secondary contacts described above. Researchers also receive information on whether a participant who cannot be contacted has been reincarcerated during follow-up. Follow-up protocol permitted interviews to occur in any prison in Victoria in these circumstances. At the time of writing, all three waves of follow-up had greater than 50% participation and more than 80% of participants had completed at least one follow-up interview.
Record linkage will be conducted at 2, 5 and 10 years post-release across the following health and justice databases: Medicare and the Pharmaceutical Benefits Scheme (federally funded healthcare), state-wide mental health, alcohol and other drug treatment, ambulance, hospital emergency department, hospital admissions, housing services, police contact (arrest, charge, victim) and mortality. Participants consented to data linkage on prison program participation, including those related to addressing offending behaviour, drug use and use of prison health services, during the sentence in which they were recruited and future periods of incarceration over 10 years. Record linkage had not commenced at the time of writing.
The Victorian Department of Justice Human Research Ethics Committee and the Alfred Hospital Ethics Committee approved the study. Specific ethical and administrative approvals for record linkage were received from the Australian Government Department of Health, the Australian Institute of Health & Welfare, Victoria Police, and the National Coronial Information System.
In this paper, we present descriptive statistics to characterise the socio-demographics, physical and mental health, incarceration history, pre-incarceration offending, drug dependence treatment history and substance use of participants. These were generated using Stata SE Version 14.1 .