In the present study, we found that HIV testing was common among Thai IDU, with 76.2% reporting that they had been tested in the past six months. Having been enrolled in voluntary drug treatment and being enrolled in the tenofovir trial was positively associated with having been tested for HIV, while having been to the MSHRC was marginally associated. Among those who had not been tested for HIV in the past six months, approximately 56% had recently engaged in some form of HIV risk behaviour. We also found that almost three-quarters of the sample (74.2%) expressed willingness to get tested for HIV at the drug-user-run MSHRC. In a multivariate analysis, having been to MSHRC was independently and positively associated with willingness to get tested at MSHRC. Enrolment in voluntary drug treatment was also associated with willingness to get tested at the MSHRC, although this relationship interacted with gender, with women in treatment being the more willing to get tested at the MSHRC.
We found that just over three-quarters (76.2%) of our sample of IDU had previously been tested for HIV in the past six months. Our findings are consistent with previous studies demonstrating fairly high levels of HIV testing in other middle-income settings contending with high rates of HIV infection among IDU, including Andhra Pradesh, India (89%) [22
] and St. Petersburg, Russia (76%) [23
]. However, our findings are inconsistent with previous studies that show low uptake of HIV testing among IDU in Asia [13
]. That said, it is unclear whether the high rate of testing observed here is partially a reflection of the existence of the tenofovir trial, as 55% of participants had enrolled in this study. Although HIV testing appears to be quite common among IDU in Bangkok, there were still a number of active drug-using participants who had not been tested in the past six months. Among the participants who were not tested for HIV, the majority perceived themselves to be HIV-negative even though they had engaged in at least one HIV risk behaviour in the past six months. This raises concern that some IDU in Thailand may be unaware of their HIV risk, indicating a need for intensified and targeted outreach, education and testing efforts to reach these individuals [9
]. Interestingly, our findings reveal that the type of illicit drugs injected (heroin, midazolam, and methamphetamine) was not associated with either of our outcome variables, suggesting that our findings are uniform across individuals who use different types of drugs.
UNODC recommends community-based, voluntary drug treatment programs across South East Asia as a substitute for incarceration and compulsory drug detention centres for IDU [25
]. Voluntary drug treatment programs, in particular opiate substitution therapy (OST), have been previously associated with a reduction in risky behaviour and HIV infection among IDU in various settings [26
]. Adding to the benefits of voluntary treatment, we found that participants who were enrolled in voluntary treatment were significantly more likely to get tested for HIV compared to those who were not enrolled in voluntary treatment. Our findings support the recommendation of the United States Centres for Disease Control and Prevention (US CDC) to integrate HIV testing services as part of voluntary drug treatment [29
]. However, concerns have been raised about the nature of current HIV testing in voluntary drug treatment centres in Thailand, as it has been reported that in some of these centres, HIV testing is mandatory and a condition of receiving services [11
]. Given that our study did not differentiate between mandatory and voluntary HIV testing in voluntary treatment programs, future research should seek to untangle this complex relationship. Nevertheless, in these settings, replacing the system of mandatory testing with voluntary HIV testing in these treatment programs may prove to be effective in increasing the proportion of IDU in Thailand who get tested, thereby allowing for early diagnosis, enhanced access to antiretroviral therapy (ART) treatment, and targeted education and interventions to control the spread of HIV [6
In addition to being enrolled in voluntary drug treatment, being enrolled in the tenofovir trial was also positively associated with HIV testing among IDU. The tenofovir trial in Thailand, sponsored by the US CDC, was launched in 2005 in an attempt to examine the safety and efficacy of this antiretroviral drug. Currently, tenofovir (alone) is being provided to approximately 2,400 HIV-negative IDU and 17 drug treatment clinics across Bangkok [30
]. Results of the US CDC-sponsored pre-exposure prophylaxis trial in Thailand are to be revealed in early 2012 [31
]. The increased odds of HIV testing among IDU in the tenofovir trial could be attributed to the fact that all participants in the trial receive free rapid HIV testing on an ongoing basis. Although our findings show a positive association between being enrolled in the tenofovir trial and HIV testing, concerns have been expressed over the fact that the trial sites in Thailand failed to provide sterile syringes and needles to IDU participants [32
]. Efforts to engage and consult with IDU community groups at an earlier stage of the trial design process may have helped alleviate these concerns and should be considered for future HIV prevention trials as a means of ensuring appropriate access to HIV prevention technologies among trial participants.
Internationally, peer outreach and peer-run initiatives have been shown to be successful in extending the reach and effectiveness of conventional public health programs, including those focused on preventing and treating HIV/AIDS among IDU [14
]. Since the launch of Thailand's 2003 "War on Drugs" campaign, the government has continued to rely on repressive approaches to drugs, including arbitrary arrests, blacklisting, drug planting by police, extrajudicial executions and other human rights violations of people involved with drugs [11
]. In this context, severe stigma and discrimination persist against Thai IDU, prompting many to avoid public health programs [37
]. Additionally, problems related to stigmatizing attitudes of health care providers focused on IDU have been reported among Thai health professionals, including nursing students, which in turn likely adversely affects the willingness of IDU to access health care [38
]. Given these problems, the noted effectiveness of various peer-based methods for IDU, and the high willingness to access HIV testing at the MSHRC, peer-based HIV testing interventions for IDU may have high potential for success in this setting. In the present study, having been to the MSHRC previously was significantly and positively associated with willingness to get HIV testing at the centre. In an earlier study conducted on the MSHRC, results showed that the main reason IDU did not access the centre was the lack of knowledge of its existence [16
]. Therefore, future efforts should focus on increasing awareness of and improving access to the MSHRC and other drop-in centres like it. Since the focus of this paper was on willingness to get HIV testing at the MSHRC without specifying whether the testing was peer-delivered, future research efforts should seek to determine whether IDU would be willing to be tested by a peer either in the context of a drug-user-run harm reduction program or in other conventional health care settings.
Enrolment in voluntary drug treatment was also associated with willingness to get HIV testing at the MSHRC. As mentioned above, there was an interaction effect involving enrolment in voluntary treatment and gender, and willingness to get tested at the MSHRC. Among participants who were not enrolled in voluntary treatment, males were significantly more willing than females to get tested at the MSHRC, although this association did not reach conventional significance. Among female IDU, those engaged in treatment were significantly more willing to get tested at the MSHRC compared to those out of treatment. In light of these findings, future research should seek to unpack the gender dynamics surrounding addiction treatment enrolment and HIV testing behaviour within this setting.
This study has several limitations. First, because of the cross-sectional nature of the study, there is an inability to determine a temporal relationship between exposure and outcome, and therefore causation cannot be inferred. Second, the data collected were self-reported and may be subject to reporting biases. Socially desirable reporting as well as recall bias may affect reports of both risk behaviour and testing behaviour. Third, since the study sample was small and not randomly selected, the study may not be representative of Thai IDU. As well, our findings may not be generalizable to other populations of IDU. Lastly, because of the small sample size, there were wide intervals around some of the estimates reported.