Factors associated with methadone treatment among injection drug users in Bangkok, Thailand

The impact of methamphetamine/amphetamine use on receipt and outcomes of medications for opioid use disorder: a systematic review

Background

Methamphetamine/amphetamine use has sharply increased among people with opioid use disorder (OUD). It is therefore important to understand whether and how use of these substances may impact receipt of, and outcomes associated with, medications for OUD (MOUD). This systematic review identified studies that examined associations between methamphetamine/amphetamine use or use disorder and 3 classes of outcomes: (1) receipt of MOUD, (2) retention in MOUD, and (3) opioid abstinence during MOUD.

Methods

We searched 3 databases (PubMed/MEDLINE, PsycINFO, CINAHL Complete) from 1/1/2000 to 7/28/2020 using key words and subject headings, and hand-searched reference lists of included articles. English-language studies of people with documented OUD/opioid use that reported a quantitative association between methamphetamine/amphetamine use or use disorder and an outcome of interest were included. Study data were extracted using a standardized template, and risk of bias was assessed for each study. Screening, inclusion, data extraction and bias assessment were conducted independently by 2 authors. Study characteristics and findings were summarized for each class of outcomes.

Results

Thirty-nine studies met inclusion criteria. Studies generally found that methamphetamine/amphetamine use or use disorder was negatively associated with receiving methadone and buprenorphine; 2 studies suggested positive associations with receiving naltrexone. Studies generally found negative associations with retention; most studies finding no association had small samples, and these studies tended to examine shorter retention timeframes and describe provision of adjunctive services to address substance use. Studies generally found negative associations with opioid abstinence during treatment among patients receiving methadone or sustained-release naltrexone implants, though observed associations may have been confounded by other polysubstance use. Most studies examining opioid abstinence during other types of MOUD treatment had small samples.

Conclusions

Overall, existing research suggests people who use methamphetamine/amphetamines may have lower receipt of MOUD, retention in MOUD, and opioid abstinence during MOUD. Future research should examine how specific policies and treatment models impact MOUD outcomes for these patients, and seek to understand the perspectives of MOUD providers and people who use both opioids and methamphetamine/amphetamines. Efforts to improve MOUD care and overdose prevention strategies are needed for this population.

Motivations to initiate injectable hydromorphone and diacetylmorphine treatment: A qualitative study of patient experiences in Vancouver, Canada

BACKGROUND

Within the context of the ongoing overdose crisis and limitations of conventional opioid treatments, the scale-up of injectable hydromorphone (HDM) and diacetylmorphine (DAM) as evidenced-based treatments is currently underway in some settings in Canada. Past research has underscored the importance of treatment initiation in shaping onward treatment trajectories, however structural factors that influence participants' motivations to access injectable HDM or DAM have not been fully characterized. This study examines peoples' motivations for accessing HDM/DAM treatment and situates these within the social and structural context that shapes treatment delivery by employing the concept of structural vulnerability.

METHODS

Fifty-two individuals enrolled in injectable HDM/DAM programs were recruited from four community-based clinical programs in Vancouver, Canada to participate in qualitative semi-structured interviews. Approximately 50 h of ethnographic fieldwork was also completed in one clinical setting, and one-on-one with participants public spaces. Interview transcripts and ethnographic fieldnotes were analyzed through a structural vulnerability lens with a focus on treatment initiation.

RESULTS

Participants' previous experiences and perceptions of other drug treatments (e.g. methadone) foregrounded their initiation of injectable HDM/DAM. Social and structural factors (e.g. fentanyl-adulterated drug supply, poverty, drug criminalization) influenced participants' motivations to address immediate physical risks and their initial perception of this treatment's ability to align with their opioid use experiences. Similar social and structural factors that drive immediate physical risks, were also evidenced in participants' motivations to make changes in their daily lives and to address broader opioid use goals.

CONCLUSION

Participants descriptions of their motivations to initiate HDM/DAM highlight how structural vulnerabilities shaped participants' experiences initiating injectable HDM/DAM.

Risky injection practices and HCV awareness in Chiang Mai Province, Thailand: a respondent-driven sampling study of people who inject drugs

Background

People who inject drugs (PWID) are the most exposed to hepatitis C virus (HCV). In Thailand, drug use is highly criminalized, and harm reduction services are scarce. This study estimates risky injection practices and assesses the proportion of HCV awareness and screening in the PWID population in Northern Thailand.

Methods

We used respondent-driven sampling (RDS) to recruit PWID in Chiang Mai Province. Social and behavioural data were collected through face-to-face interviews at an addiction treatment facility. Weighted population estimates were calculated to limit biases related to the non-random sampling method. Univariate and multivariate analyses were performed to study factors associated with HCV awareness and screening.

Results

One hundred seventy-one PWID were recruited between April 2016 and January 2017. Median age was 33 (Interquartile range: 26–40) years, 12.2% were women, and 49.4% belonged to a minority ethnic group. Among participants, 76.8% injected heroin, 20.7% methadone, and 20.7% methamphetamine. We estimate that 22.1% [95% CI: 15.7–28.6] of the population had shared needles in the last 6 months and that 32.0% [95% CI: 23.6–40.4] had shared injection material. Only 26.6% [95% CI: 17.6–35.6] had heard of HCV. Factors independently associated with knowledge of HCV included belonging to a harm reduction organization (adjusted odds ratio (aOR) = 5.5 [95% CI: 2.0–15.3]) and voluntary participation in a drug rehabilitation programme (aOR = 4.3 [95% CI: 1.3–13.9]), while Lahu ethnicity was negatively associated (aOR = 0.3 [95% CI: 0.1–0.9]). We estimate that 5% of the PWID population were screened for HCV; the only factor independently associated with being screened was membership of a harm reduction organization (aOR = 5.7 [95% CI: 1.6–19.9]).

Conclusion

Our study reveals that the PWID population is poorly informed and rarely screened for HCV, despite widespread risky injection practices. A public health approach aimed at reducing the incidence of HCV should target the PWID population and combine harm reduction measures with information and destigmatization campaigns. Civil society organizations working with PWID are a major asset for the success of such an approach, based on their current positive interventions promoting awareness of and screening for HCV.

Regional differences between people who inject drugs in an HIV prevention trial integrating treatment and prevention (HPTN 074): a baseline analysis

INTRODUCTION

People who inject drugs (PWID) experience high HIV incidence and face significant barriers to engagement in HIV care and substance use treatment. Strategies for HIV treatment as prevention and substance use treatment present unique challenges in PWID that may vary regionally. Understanding differences in the risk structure for HIV transmission and disease progression among PWID is essential in developing and effectively targeting intervention strategies of HIV treatment as prevention.

METHODS

We present a baseline analysis of HIV Prevention Trials Network (HPTN) 074, a two-arm, randomized controlled trial among PWID in Indonesia (n = 258), Ukraine (n = 457) and Vietnam (n = 439). HPTN 074 was designed to determine the feasibility, barriers and uptake of an integrated intervention combining health systems navigation and psychosocial counselling for the early engagement of antiretroviral therapy (ART) and substance use treatment for PWID living with HIV. Discordant PWID networks were enrolled, consisting of an HIV-positive index and their HIV-negative network injection partner(s). Among the enrolled cohort of 1154 participants (502 index participants and 652 network partners), we examine regional differences in the baseline risk structure, including sociodemographics, HIV and substance use treatment history, and injection and sexual risk behaviours.

RESULTS

The majority of participants were male (87%), with 82% of the enrolled females coming from Ukraine. The overall mean age was 34 (IQR: 30, 38). Most commonly injected substances included illegally manufactured methadone in Ukraine (84.2%), and heroin in Indonesia (81.8%) and Vietnam (99.5%). Injection network sizes varied by region: median number of people with whom participants self-reported injecting drugs was 3 (IQR: 2, 5) in Indonesia, 5 (IQR: 3, 10) in Ukraine and 3 (IQR: 2, 4) in Vietnam. Hazardous alcohol use, assessed using the Alcohol Use Disorders Identification Test - Alcohol Consumption Questions (AUDIT-C), was prominent in Ukraine (54.7%) and Vietnam (26.4%). Reported sexual risk behaviours in the past month, including having two or more sex partners and giving/receiving money or drugs in exchange for sex, were uncommon among all participants and regions.

CONCLUSIONS

While regional differences in risk structure exist, PWID particularly in Ukraine need immediate attention for risk reduction strategies. Substantial regional differences in risk structure will require flexible, tailored treatment as prevention interventions for distinct PWID populations.

Barriers to retention in methadone maintenance therapy among people who inject drugs in Bangkok, Thailand: a mixed-methods study

BACKGROUND

Methadone maintenance therapy (MMT) is a mainstay for treating opioid use disorder and preventing and managing HIV among people who inject drugs (PWID). While previous research suggested low dosing of methadone and high rates of discontinuation of MMT among PWID in Thailand, little is known about patients' lived experiences with MMT in this setting. Therefore, we conducted a mixed-methods study to examine barriers to retention in MMT among PWID in Bangkok, Thailand, with particular attention to methadone dosing.

METHODS

Bivariate statistics were used to analyze quantitative survey data collected from methadone-treated PWID between July and October 2011. Qualitative data collected through semi-structured interviews with 16 methadone-treated PWID between July 2011 and June 2012 were analyzed thematically, with a focus on individual-level, social-structural, and environmental barriers to accessing MMT.

RESULTS

Among 158 survey participants, a median dosage of methadone was 30 mg/day (interquartile range 20-50). Of these, 15.8% reported having acquired street methadone due to low prescribed dosages of methadone and 19.0% reported recent syringe sharing. Qualitative interview data indicated some methadone provider-related barriers, including discouraging patients from using methadone due to it being a Western medicine, difficulty negotiating higher doses of methadone, and abrupt dose reductions without patient consultation (involving the provision of non-medicated "syrup" in some cases). Social-structural and environmental barriers to optimal MMT access included intense police surveillance of methadone clinics; and frequent incarceration of PWID and a lack of access to methadone in prisons.

CONCLUSIONS

Among our sample of methadone-treated PWID, methadone dosages were suboptimal according to the international guidelines. Poor adherence to international guidelines for opioid agonist therapies, aggressive law enforcement, and a lack of methadone in prisons need to be addressed to optimize MMT and reduce harms associated with untreated opioid use disorder in Thailand.

Effectiveness of the behavior change intervention to improve harm reduction self-efficacy among people who inject drugs in Thailand

BACKGROUND

People who inject drugs (PWID) in Thailand reported unsafe injection practices resulting in injection-related health consequences. Harm reduction self-efficacy plays an important role and could be improved to reduce harm associated with injecting drugs. Evidence-based interventions targeting PWID are needed. This study sought to evaluate the effectiveness of the behavior change intervention within the PWID population.

METHODS

The behavior change intervention, Triple-S, was designed to improve harm reduction self-efficacy among PWID. This quasi-experimental study was a pre- and post-comparison with a control group design. Participants were PWID, aged 18-45 years, and located in Bangkok. Changes in harm reduction self-efficacy of the intervention group were compared with the control group using paired and independent t-test.

RESULTS

Most of PWID were male (84%), had a secondary school and lower education (71%), were single, and had a mean age of 41 years. They had been injecting drugs for an average of 20 years, and the median of drug injections per week was ten times in the past month. Pre- and post-intervention effects were measured and results showed that the intervention group reported improvement in harm reduction self-efficacy in negative emotional conditions (P=0.048).

CONCLUSION

Our findings suggest that Triple-S intervention can significantly improve harm reduction self-efficacy in negative emotional conditions. The results may suggest the importance of behavior change intervention, especially when integrated with services provided by drop-in centers. The intervention can be further developed to cover other harm reduction behaviors and improve harm reduction self-efficacy.

Determinants of willingness to enroll in opioid agonist treatment among opioid dependent people who inject drugs in Ukraine

BACKGROUND

Coverage with opioid agonist treatments (OAT) that include methadone and buprenorphine is low (N=8400, 2.7%) for the 310,000 people who inject drugs (PWID) in Ukraine. In the context of widespread negative attitudes toward OAT in the region, patient-level interventions targeting the barriers and willingness to initiate OAT are urgently needed.

METHODS

A sample of 1179 PWID with opioid use disorder not currently on OAT from five regions in Ukraine was assessed using multivariable logistic regression for independent factors related to willingness to initiate OAT, stratified by their past OAT experience.

RESULTS

Overall, 421 (36%) PWID were willing to initiate OAT. Significant adjusted odds ratios (aOR) for covariates associated with the willingness to initiate OAT common for both groups included: higher injection frequency (previously on OAT: aOR=2.7; never on OAT: aOR=1.8), social and family support (previously on OAT: aOR=2.0; never on OAT: aOR=2.0), and positive attitude towards OAT (previously on OAT: aOR=1.3; never on OAT: aOR=1.4). Among participants previously on OAT, significant correlates also included: HIV-negative status (aOR=2.6) and depression (aOR=2.7). Among participants never on OAT, however, living in Kyiv (aOR=4.8) or Lviv (aOR=2.7), previous imprisonment (aOR=1.5), registration at a Narcology service (aOR=1.5) and recent overdose (aOR=2.6) were significantly correlated with willingness to initiate OAT.

CONCLUSIONS

These findings emphasize the need for developing interventions aimed to eliminate existing negative preconceptions regarding OAT among PWID with opioid use disorder in Ukraine, which should be tailored to meet the needs of specific characteristics of PWID in geographically distinct setting based upon injection frequency, prior incarceration, and psychiatric and HIV status.

Dose-response relationship between methadone dose and adherence to antiretroviral therapy among HIV-positive people who use illicit opioids

BACKGROUND AND AIMS

For HIV-positive individuals who use illicit opioids, engagement in methadone maintenance therapy (MMT) can contribute to improved HIV treatment outcomes. However, to our knowledge, the role of methadone dosing in adherence to antiretroviral therapy (ART) has not yet been investigated. We sought to examine the relationship between methadone dose and ART adherence among a cohort of people who use illicit opioids.

DESIGN AND SETTING

We used data from the AIDS Care Cohort to Evaluate Access to Survival Services (ACCESS) study, an ongoing prospective observational cohort of HIV-positive people who use illicit drugs in Vancouver, Canada, linked confidentially to comprehensive HIV treatment data in a setting of universal no-cost medical care, including medications. We evaluated the longitudinal relationship between methadone dose and the likelihood of ≥ 95% adherence to ART among ART-exposed participants during periods of engagement in MMT.

PARTICIPANTS

Two hundred and ninety-seven ART-exposed individuals on MMT were recruited between December 2005 and May 2013 and followed for a median of 42.1 months.

MEASUREMENTS

We measured methadone dose at ≥ 100 versus < 100 mg/day and the likelihood of ≥ 95% adherence to ART.

FINDINGS

In adjusted generalized estimating equation (GEE) analyses, MMT dose ≥ 100 mg/day was associated independently with optimal adherence to ART [adjusted odds ratio (AOR) = 1.38; 95% confidence interval (CI) = 1.08-1.77). In a subanalysis, we observed a dose-response relationship between increasing MMT dose and ART adherence (AOR = 1.06 per 20 mg/day increase, 95% CI = 1.00-1.12).

CONCLUSION

Among HIV-positive individuals in methadone maintenance therapy, those receiving higher doses of methadone (≥ 100 mg/day) are more likely to achieve ≥ 95% adherence to antiretroviral therapy than those receiving lower doses.

Perceived barriers to utilise methadone maintenance therapy among male injection drug users in rural areas of southern Thailand

INTRODUCTION AND AIMS

Methadone maintenance therapy (MMT) has been proven to be effective and cost-effective in treating dependence on opioids. However, concerns remain that geographical, financial and other hidden barriers may hinder access to MMT, especially in rural areas where health services are limited. The objective of this study was to determine factors associated with utilisation of MMT by injection drug users (IDUs) living in Songkhla province.

DESIGN AND METHODS

A cross-sectional study among 159 IDUs in Songkhla province of southern Thailand was conducted. Participants were recruited using a snowball technique. Data were collected from July 2013 to January 2014 via face-to-face interviews.

RESULTS

Around one-forth (24.5%) of participants had difficulties travelling to MMT clinics because of the long distance, long travelling time and lack of a private vehicle. Twenty-four percent faced difficulties with the clinic's opening hours and 28% faced difficulties paying for the cost of travel. IDUs who utilised the MMT perceived risks of injection drug use differently compared with those who did not. Younger or Muslim IDUs were less likely to attend MMT. IDUs who perceived that MMT was effective were more likely to utilise MMT.

DISCUSSION AND CONCLUSIONS

Physical accessibility, affordability and acceptability play an essential role in MMT utilisation. Developing alternatives that reduce the travelling time, costs for IDUs and more convenient operation hours to suit their lifestyles may increase the utilisation of MMT. Intensive consultation before starting MMT is highly recommended.

The impact of methadone maintenance therapy on hepatitis C incidence among illicit drug users

AIMS

To determine the relationship between methadone maintenance therapy (MMT) and hepatitis C (HCV) seroconversion among illicit drug users.

DESIGN

A generalized estimating equation model assuming a binomial distribution and a logit-link function was used to examine for a possible protective effect of MMT use on HCV incidence.

SETTING

Data from three prospective cohort studies of illicit drug users in Vancouver, Canada between 1996 and 2012.

PARTICIPANTS

A total of 1004 HCV antibody-negative illicit drug users stratified by exposure to MMT.

MEASUREMENTS

Baseline and semi-annual HCV antibody testing and standardized interviewer-administered questionnaire soliciting self-reported data relating to drug use patterns, risk behaviors, detailed socio-demographic data and status of active participation in an MMT program.

FINDINGS

One hundred and eighty-four HCV seroconversions were observed for an HCV incidence density of 6.32 [95% confidence interval (CI) = 5.44-7.31] per 100 person-years. After adjusting for potential confounders, MMT exposure was protective against HCV seroconversion [adjusted odds ratio (AOR) = 0.47; 95% CI = 0.29-0.76]. In subanalyses, a dose-response protective effect of increasing MMT exposure on HCV incidence (AOR = 0.87; 95% CI = 0.78-0.97) per increasing 6-month period exposed to MMT was observed.

CONCLUSION

Participation in methadone maintenance treatment appears to be highly protective against hepatitis C incidence among illicit drug users. There appears to be a dose-response protective effect of increasing methadone exposure on hepatitis C incidence.

Compulsory drug detention and injection drug use cessation and relapse in Bangkok, Thailand

INTRODUCTION AND AIMS

Strategies to promote the reduction and cessation of injection drug use are central to human immunodeficiency virus prevention and treatment efforts globally. Though drug use cessation is a major focus of drug policy in Thailand, little is known about factors associated with injection cessation and relapse in this setting.

DESIGN AND METHODS

A cross-sectional study was conducted between July and October 2011 of a community-recruited sample of people who inject drugs in Bangkok, Thailand. Using multivariate logistic regression, we examined the prevalence and correlates of injection drug use cessation with subsequent relapse.

RESULTS

Among 422 participants, 209 (49.5%) reported a period of injection drug use cessation of at least one year. In multivariate analyses, incarceration (adjusted odds ratio [AOR] 13.07), voluntary drug treatment (AOR 2.75), midazolam injection (AOR 2.48) and number of years since first injection (AOR 1.07) were positively associated with injection cessation of duration greater than a year (all P < 0.05). Exposure to compulsory drug detention was positively associated (AOR 2.61) and methadone treatment was negatively associated (AOR 0.38) with short-term cessation only. Injection drug use cessation was most often due to incarceration (74%), and relapse was associated with release from prison (66%).

DISCUSSION AND CONCLUSION

Half of the study participants had previously stopped injecting drugs for more than a year, and this was strongly associated with incarceration. Compulsory drug detention was associated with short-term cessation and relapse. A range of evidence-based strategies should be made available to facilitate sustained cessation of injection drug use in Thailand.

A call for evidence-based medical treatment of opioid dependence in the United States and Canada

Despite decades of experience treating heroin or prescription opioid dependence with methadone or buprenorphine--two forms of opioid substitution therapy--gaps remain between current practices and evidence-based standards in both Canada and the United States. This is largely because of regulatory constraints and pervasive suboptimal clinical practices. Fewer than 10 percent of all people dependent on opioids in the United States are receiving substitution treatment, although the proportion may increase with expanded health insurance coverage as a result of the Affordable Care Act. In light of the accumulated evidence, we recommend eliminating restrictions on office-based methadone prescribing in the United States; reducing financial barriers to treatment, such as varying levels of copayment in Canada and the United States; reducing reliance on less effective and potentially unsafe opioid detoxification; and evaluating and creating mechanisms to integrate emerging treatments. Taking these steps can greatly reduce the harms of opioid dependence by maximizing the individual and public health benefits of treatment.

Factors associated with one year retention to methadone maintenance treatment program among patients with heroin dependence in China

Objective

The aim of this study was to evaluate the risk factors associated with dropout from Methadone Maintenance Treatment (MMT) clinics within a 1 year follow-up cohort study in China.

Methods

A data analysis is to explore the adherence of MMT during one year from three hundred and twenty patients with heroin dependence at five clinics (3 in Shanghai, 2 in Kunming) in China. All participants were from the part of China-United States cooperation project entitled “Research about improving the compliance and efficacy of methadone maintenance treatment in China”. Our data analysis includes the patients’ attendance in the 6 months clinical study and the data in another 6 months afterward. The data of patients at baseline were collected with the Addiction Severity Index (ASI) which is a semi-structured questionnaire covering socio-demographic characteristics and drug use history. The one year attendance after recruitment at the clinics and daily dose were abstracted from the MMT clinic register system. The Cox proportional hazards model were used to explore the risk factor of dropout, defined as seven consecutive days without methadone.

Results

By the end of 1 year of treatment 86 patients still remained in MMT without dropout (87% in Shanghai and 13% patients in Kunming). Over the entire 1-year period the median days of remaining in the program were 84 days (in Shanghai and Kunming were 317 days and 22 days).The factors associated with retention included age (HR = 0.98, 95%C.I.:0.96-0.99, P = 0.0062) and ASI alcohol scores (HR = 5.72, 95%C.I.:1.49-21.92, P = 0.0109) at baseline.

Conclusion

One year retention of newly recruited patients with heroin dependence was related to age and ASI alcohol scores at baseline. The adherence is poorer for the patients who are young and having more serious alcohol problems.

Moving toward personalized medicine in the methadone maintenance treatment program: a pilot study on the evaluation of treatment responses in Taiwan

This pilot study simultaneously evaluated the effects of various factors, including genetic variations of CYP2B6, CYP2C19, and ABCB1, demographic characteristics, disease states, methadone-drug interactions (MDIs), and poly-substance use, on the treatment responses among non-HIV patients in the methadone maintenance treatment program (MMTP) in Taiwan. A total of 178 patients were recruited from two major hospitals that provided MMTP services in southern Taiwan, and information regarding concomitant medications and diseases was acquired from the National Health Insurance (NHI) program. The results demonstrated that the methadone maintenance dose, CYP2B6 785G allele, and ABCB1 2677T allele have positive effects on the methadone plasma concentration. In contrast, patients with HCV coinfection, alcohol problems, and psychiatric diseases may have a negative response to treatment. Thus, a comprehensive evaluation of treatment responses in the MMTP should include not only genetic polymorphisms in methadone metabolism and transporter proteins, but also concomitant diseases, MDIs, and poly-substance use. The results also suggest that personalized medicine may be indispensable for a better outcome of the MMTP.

Drug-related harm among people who inject drugs in Thailand: summary findings from the Mitsampan Community Research Project

Background

For decades, Thailand has experienced high rates of illicit drug use and related harms. In response, the Thai government has relied on drug law enforcement to address this problem. Despite these efforts, high rates of drug use persist, and Thailand has been contending with an enduring epidemic of human immunodeficiency virus (HIV) among people who inject drugs (IDU).

Methods

In response to concerns regarding drug-related harm in Thailand and a lack of research focused on the experiences and needs of Thai IDU, the Mitsampan Community Research Project was launched in 2008. The project involved administering surveys capturing a range of behavioral and other data to community-recruited IDU in Bangkok in 2008 and 2009.

Results

In total, 468 IDU in Bangkok were enrolled in the project. Results revealed high rates of midazolam injection, non-fatal overdose and incarceration. Syringe sharing remained widespread among this population, driven primarily by problems with access to syringes and methamphetamine injection. As well, reports of police abuse were common and found to be associated with high-risk behavior. Problems with access to evidence-based drug treatment and HIV prevention programs were also documented. Although compulsory drug detention centers are widely used in Thailand, data suggested that these centers have little impact on drug use behaviors among IDU in Bangkok.

Conclusions

The findings from this project highlight many ongoing health and social problems related to illicit drug use and drug policies in Bangkok. They also suggest that the emphasis on criminal justice approaches has resulted in human rights violations at the hands of police, and harms associated with compulsory drug detention and incarceration. Collectively, the findings indicate the urgent need for the implementation of evidence-based policies and programs in this setting.

High rates of midazolam injection and associated harms in Bangkok, Thailand

AIMS

To identify the prevalence and correlates of midazolam injection among injecting drug users in Thailand.

DESIGN

Serial cross-sectional mixed-methods study.

SETTING

Bangkok, Thailand.

PARTICIPANTS

  A total of 435 adults who had injected drug(s) in the past 6 months were recruited through peer outreach and word of mouth in Bangkok in 2011.

MEASUREMENTS

Multivariable logistic regression was used to analyze self-reported data collected through an interviewer-administered survey in July-October 2011 (n = 435). Additionally, qualitative data were collected in June-July 2009 (n = 10) and analyzed to explore the health problems attributable to midazolam injection.

FINDINGS

Among 435 survey participants, the prevalence of daily midazolam injection in the past 6 months was 37.0% (95% confidence interval: 32-42). While 75.8% of the daily midazolam injectors identified heroin as their drug of choice, 91.8% of these individuals reported substituting heroin with midazolam when heroin was unavailable. In multivariable analyses, daily midazolam injection was associated with femoral vein injection [adjusted odds ratio (AOR) = 4.48], polydrug use (AOR = 4.94), daily heroin injection (AOR = 3.25), binge use (AOR = 1.75) and perceived increase in policing pressure (AOR = 1.95) (all P < 0.05). Qualitative accounts indicated severe health problems associated with midazolam injection, including nerve and vascular injuries.

CONCLUSION

Midazolam misuse is increasing among injecting drug users in Bangkok and appears to be used primarily as a substitute for heroin. Midazolam injection was associated independently with various risk factors for injection-related complications. Given the many deleterious effects of midazolam injection, novel interventions for midazolam injectors are needed urgently.