Research paperDirectly observed therapy programmes for anti-retroviral treatment amongst injection drug users in Vancouver: Access, adherence and outcomes
Introduction
Dramatic reductions in HIV associated morbidity and mortality can be attributed to the effectiveness of highly active anti-retroviral therapy (HAART) (Hogg et al., 1999, Porter et al., 2003). However, this success has not been replicated amongst injection drug users (IDUs) and other marginalised groups due to reduced uptake and lower rates of adherence to treatment (Palepu et al., 2003; Shannon, Bright, Duddy, & Tyndall, 2005; Strathdee, Palepu, et al., 1998; Wood et al., 2003). Ongoing injection drug use, especially cocaine injection, has been shown to be strongly associated with reduced adherence to anti-retrovirals (ARVs) (Arnsten et al., 2002, Vlahov et al., 2005, Wood et al., 2004). Although many HIV positive IDUs have good therapeutic outcomes on ARVs and a number of existing programmes have contributed to improvements in health status, success at a population level remains elusive (Carrieri et al., 2003; Cohen, Wu, & Farley, 2004; Strathdee, van Ameijden, et al., 1998; Vlahov et al., 2005). Concurrent treatment for addictions, such as methadone maintenance therapy, has been shown to play an important role in increasing ARV adherence but this is not available in all settings and treatment for opiate addiction only captures a proportion of IDUs (Lucas, Flexner, & Moore, 2002; Palepu et al., 2006; Sambamoorthi, Warner, Crystal, & Walkup, 2000). In addition, there are some reports that IDUs may have reduced immunologic outcomes to ARVs despite complete viral suppression (Dronda et al., 2004).
In the Province of British Columbia, where ARVs are supplied free of charge, it was shown that between 1995 and 2001, 33% of deaths due to HIV/AIDS occurred in those who had never received ARVs (Wood et al., 2003). Uptake and adherence to therapy amongst marginalised groups is impeded by a range of structural, social and psychological factors and therefore a comprehensive approach to treatment is needed to optimise therapeutic outcomes (Howard et al., 2002, Knowlton et al., 2006, Moss et al., 2004, Wohl et al., 2006; Wood, Kerr, et al., 2006). HIV programmes that employ directly observed treatment (DOT) for ARVs have been developed and found to be a useful model to increase adherence to HIV medications (Bangsberg, Mundy, & Tulsky, 2001; Conway et al., 2004, McCance-Katz et al., 2002). This approach is also very conducive to monitoring co-morbidities, toxicities, and outcomes and the long-term engagement of the clients may also promote entry into addiction treatment (Altice et al., 2004).
An explosive HIV epidemic amongst IDUs occurred in the Downtown Eastside (DTES) of Vancouver during the 1990s and the prevalence of HIV amongst IDUs in this community is over 25% (Strathdee et al., 1997, Tyndall et al., 2003). It is estimated that there are over 5000 injection drug users in the 10 square city blocks that make up the DTES and there have been over 6000 different individuals who have used the local supervised injection facility that was opened in September 2003 (Spittal et al., 2002, Tyndall et al., 2005). The disparities in health care utilisation and HIV infections in this community are especially apparent amongst women and people of Aboriginal ethnicity (Craib et al., 2003, Spittal et al., 2002). It is known that large numbers of marginalised women are not accessing services of any kind and the uptake of ARV therapy is limited in this community and elsewhere (Shannon et al., 2005, Solomon et al., 1998).
In response to the increasing numbers of individuals requiring ARV therapy and the challenges of access and adherence, support programmes geared towards people with addictions have been developed. The aim of this paper is to measure ARV access, adherence and outcomes amongst illicit drug users from two programmes located in the DTES of Vancouver.
Section snippets
HIV/AIDS drug treatment programme
In the province of British Columbia, ARVs are distributed free of charge to all eligible HIV infected individuals through the BC Centre for Excellence in HIV/AIDS Drug Treatment Programme (DTP). The guidelines for this distribution are determined by the Therapeutic Guidelines Committee and are consistent with the recommendations put forward by the International AIDS Society, USA. Plasma viral load testing is collected within the DTP and for the purpose of this study, we used a viral load result
Results
Table 1 shows the characteristics for the 297 clients who received ARVs stratified by the two clinic sites. The mean age at enrollment was 40.5 years, 73% were males, and 44% were of Aboriginal ethnicity. The mean CD4 count at baseline was 248 cells/mm3, with 142 (47%) starting therapy with a CD4 count below 200 cells/mm3. The plasma viral load at the beginning of therapy was over 100,000 copies/ml in 73 (25%). Hepatitis C co-infection was present in 85% of participants based on a positive
Discussion
The two ARV support programmes evaluated in this study demonstrate the relatively high rates of adherence and viral load suppression that can be achieved through comprehensive supportive programmes. It also illustrates the frequency of treatment interruptions and the extremely high mortality rates observed in programme participants. Those who started ARVs with CD4 counts below 200 cells/mm3 had higher mortality rates.
Through detailed daily records of ARV dispensing and observed ingestion we were
Acknowledgements
The authors wish to thank Shelly Dean, the clinic staff and the participants at the MAT Programme and Doreen Littlejohn, the clinic staff and participants at the Positive Outlook Programme. Dr. Tyndall is supported by the Michael Smith Foundation for Health Research. Dr. Kerr is supported by the Michael Smith Foundation for Health Research and the Canadian Institutes for Health Research.
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