I-Track - Enhanced Surveillance of HIV, Hepatitis C and associated risk behaviours among people who inject drugs in Canada: Phase 2 Report

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Table of contents

• Executive Summary
  • Introduction
  • I-Track Primary Objectives (Phase 2)
  • Overview of I-Track Methods
  • Report Objective
  • Data Analysis
  • Summary of I-Track Phase 2 Results
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Executive Summary

Introduction

The Public Health Agency of Canada (PHAC) is responsible for coordinating the federal response to HIV/AIDS, as described in the Federal Initiative to Address HIV/AIDS in Canada (FI). One of the key components of the FI is knowledge development, which includes the establishment of sentinel surveillance programs for vulnerable populations. Since 2002, PHAC’s Centre for Communicable Diseases and Infection Control (CCDIC) has developed and implemented the I-Track surveillance system in collaboration with local and provincial health departments and community-based organizations.

I-Track Primary Objectives (Phase 2)

I-Track is an enhanced surveillance system that monitors HIV and hepatitis C as well as the associated risk behaviours among people who inject drugs in Canada by combining behavioural and biological surveillance. I-Track’s primary objectives aim to describe:

• the prevalence of HIV and hepatitis C;
• drug use, injecting, and sexual behaviours;
• HIV and hepatitis C testing behaviour;
• care and treatment history of HIV and hepatitis C;
• core knowledge of HIV-related risk behaviours, modes of transmission, and risk-reduction strategies; and
• trends in prevalence and core behavioural measures over time.

Overview of I-Track Methods

The I-Track system involves implementing periodic cross-sectional surveys among people who inject drugs in sentinel sites across Canada. Information on demographic characteristics, drug use, injecting and sexual risk behaviours, and HIV and hepatitis C testing and treatment history are collected through interviewer-administered, face-to-face paper questionnaires followed by the collection of a biological sample (dried blood specimen or oral fluid exudate) that is tested for HIV and hepatitis C antibodies. Sentinel sites have the option of adding site-specific questions to address particular issues or program features in the target population. Participants are recruited through venue-based convenience sampling. Participation, which is voluntary, is completely anonymous and requires informed consent.

Report Objective

This report presents descriptive findings from I-Track Phase 2 surveys that were conducted between June 1, 2005, and November 28, 2008, at participating sentinel sites in Canada. The results are intended to inform HIV prevention and control efforts, public health policy development and program evaluation. They also provide a baseline for formulating questions for more complex analyses.

Data Analysis

A total of 3076 eligible participants with complete data were available for the analyses in this report. The data are shown in tabular format to allow for comparisons across sentinel sites and with the national I-Track sample as a whole. Unless otherwise stated, the results are based on the survey participants’ report of their behaviours in the 6 months prior to their interview. Analyses were stratified by sex where numbers were large enough to facilitate meaningful interpretation. Statistical procedures were neither used to compare findings across sentinel sites nor applied to any of the data in this report.

Summary of I-Track Phase 2 Results

Participant overview and socio-demographic characteristics

• Of the I-Track Phase 2 participants, 67.8% were male, average age was 37.5 years, and 53.9% had not completed high school.
• Participants were of diverse ethnic backgrounds with 57.8% identifying as Canadian or American and 26.3% as Aboriginal.
• Over one-quarter had lived in at least one city other than where the interview took place during the 6 months prior to the interview (26.1%), indicating that this population was somewhat mobile.
• More than half reported living in unstable housing (for example, on the street) sometime during the 6 months prior to the interview (60.8%).

Drug use and injecting behaviours

• Drugs commonly injected included cocaine (81.7%), non-prescribed morphine (40.4%), oxycodone (39.0%), heroin (28.1%), and hydromorphone (26.5%).
• Cocaine was the drug most often injected in both the 6 months (53.1%) and the 1 month prior to the interview (48.0%).
• Use of opioid analgesics (such as non-prescribed morphine, heroin, hydromorphone, oxycodone) by both injection and non-injecting routes was commonly reported.
• Just over half of participants reported injecting drugs most often in their own apartment or house (52.4%); however, nearly one-quarter reported injecting drugs in public places (23.3%).
• A notable proportion of participants reported injecting with previously used needles and/or syringes (21.9%) and/or other injection equipment (33.9%).

Sexual behaviours

• The I-Track Phase 2 participants reported high-risk sexual behaviours, such as multiple sexual partners, inconsistent condom use, and sex trade work.
• The proportion of participants who reported using a condom the last time they had sex was 38.7%, which was higher than the 2008 global rate reported by UNAIDS (22%).
• In general, condom use during penetrative sex was more frequent than during oral sex. Condom use was less frequently practiced with regular and casual sex partners than with client or paid sex partners.

HIV and Hepatitis C seroprevalence and testing

• HIV seroprevalence among I-Track participants was high. Of those participants who provided a biological sample of sufficient quantity for testing, 13.2% tested positive for HIV, from 2.5% in Kingston to 19.9% in the SurvUDI network.

• HIV seroprevalence was 11.4% among female participants, from 1.3% in Kingston to 22.2% in Prince George. Of male participants, HIV seroprevalence was 14.1%, from 3.3% in Kingston to 21.6% in the SurvUDI network.
• Of those who tested positive for HIV, 20.3% were unaware of their HIV-positive status.
• Lifetime exposure to hepatitis C infection was also high (69.1%), from 51.4% in Thunder Bay to 76.7% in Prince George. Similar proportions were observed among both female and male participants.
• The proportion of participants seropositive for both HIV and hepatitis C was 11.6%. More than half of the survey participants were seropositive for hepatitis C only (57.5%); a small proportion were seropositive for HIV only (1.7%); and nearly one-third tested negative for both viruses (29.2%).
• A large proportion of the participants had ever tested for either HIV or hepatitis C (92.0% and 90.8%, respectively), and more than one-half had been tested in the year prior to the survey interview (67.9% and 56.8%, respectively).

Care and treatment history of HIV and Hepatitis C

• A large proportion of the participants who reported being HIV-positive were under the care of a doctor (89.4%) and were currently taking medications prescribed for their HIV infection (79.8%).
• Lower proportions for these measures were noted for participants who reported being hepatitis C-positive (51.0% and 36.8%, respectively).

Strengths and limitations

I-Track data are collected by cross-sectional surveys, and while it is not possible to examine causality directly, these surveillance data offer a valuable source of information critical to treatment and prevention services and programs at local, provincial, and national levels.

I-Track uses non-random, convenience sampling methods to overcome some of the inherent difficulties in accessing this hard-to-reach population. Given this, the surveillance findings may not be representative of all people who inject drugs in Canada.

With the exception of the laboratory results, this report’s findings are based on self-reported data, which are subject to social desirability bias. Therefore, under-reporting of some risk behaviours may have occurred.

Standardized surveillance system core objectives, core questions, inclusion criteria, sampling, and recruitment strategies were consistently implemented, allowing for comparison across sentinel sites and over multiple survey implementation phases. However, the findings in this report should be interpreted with caution as the regional variations observed may not be reflected in national-level data and any differences in the cross-phase comparisons may be also due to temporal or regional variations. Further, no statistical procedures were used to compare findings across sentinel sites and no adjustments were made for variations in sentinel site sample sizes.

Conclusions

The results shown in this report provide an important reference point for monitoring trends in demographic characteristics, drug use, injecting and sexual risk behaviours, testing patterns, and prevalence of HIV and hepatitis C infection among people who inject drugs in Canada.

The results from the participating sentinel sites confirmed that the prevalence of HIV and hepatitis C infection remains high among people who inject drugs. Many people who inject drugs reported injecting practices that reduce risk as well as safe sex strategies; however, reported levels of injecting and sexual risk behaviours suggest that people who inject drugs continue to represent an important risk group for HIV acquisition and transmission in Canada’s HIV epidemic.

The I-Track surveillance system is the result of successful collaboration between federal, provincial, and local governments as well as other local organizations. Refinement is ongoing; with the collaboration of a National Working Group and following the surveillance system objectives, changes to the national core question content and aspects of the system design have been incorporated into future phases. Phase 3 was conducted between April 2010 and August 2012 in 11 sentinel sites. It successfully implemented a revised questionnaire using an electronic data collection tool. The questionnaire included new core questions related to history of incarceration, opioid maintenance treatment, income and employment, and access to health care. Plans for a Phase 3 national report are underway.

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