Factors associated with willingness to take extended release naltrexone among injection drug users.

BACKGROUND: Although opioid-agonist therapy with methadone or buprenorphine/naloxone is currently the mainstay of medical treatment for opioid use disorder, these medications often are not well accepted or tolerated by patients. Recently, extended release naltrexone (XR-NTX), an opioid antagonist, has been advanced as an alternative treatment. The willingness of opioid-addicted patients to take XR-NTX has not been well described. METHODS: Opioid-using persons enrolled in a community-recruited cohort in Vancouver, Canada, were asked whether or not they would be willing to take XR-NTX. Logistic regression was used to independently identify factors associated with willingness to take the medication. RESULTS: Among the 657 participants surveyed between June 1, 2013, and November 30, 2013, 342 (52.1%) were willing to take XR-NTX. One factor positively associated with willingness was daily heroin injection (adjusted odds ratio [AOR] = 1.53; 95% confidence interval [CI] = 1.02-2.31), whereas Caucasian ethnicity was negatively associated (AOR = 0.59; 95% CI = 0.43-0.82). Satisfaction with agonist therapy (13.4%) and unwillingness to stop opioids being used for pain (26.9%) were the most common reasons for being unwilling to take XR-NTX. CONCLUSIONS: A high level of willingness to take XR-NTX was observed in this setting. Interestingly, daily injection heroin use was positively associated with willingness, whereas Caucasian participants were less willing to take XR-NTX. Although explanations for unwillingness were described in this study, further research is needed to investigate real-world acceptability of XR-NTX as an additional option for the treatment of opioid use disorder.

Factors associated with willingness to participate in a pharmacologic addiction treatment clinical trial among people who use drugs.

BACKGROUND AND OBJECTIVES: Although new medications are needed to address the harms of drug addiction, rates of willingness to participate in addiction treatment trials among people who use drugs (PWUD), have not been well characterized. METHODS: One thousand twenty PWUD enrolled in two community-recruited cohorts in Vancouver, Canada, were asked whether they would be willing to participate in a pharmacologic addiction treatment trial. Logistic regression was used to identify factors independently associated with a willingness to participate. RESULTS: Among the 1,020 PWUD surveyed between June 1, 2013 and November 30, 2013, 58.3% indicated a willingness to participate. In multivariate analysis, factors independently associated with a willingness to participate in a pharmacologic addiction treatment trial included: daily heroin injection (Adjusted Odds Ratio [AOR] = 1.75; 95% Confidence Interval [CI]: 1.13 - 2.72); daily crack smoking (AOR = 1.81; 95% CI: 1.23 - 2.66); sex work involvement (AOR = 2.22; 95% CI: 1.21 - 4.06); HIV seropositivity (AOR = 1.49; 95% CI: 1.15 - 1.94); and methadone maintenance therapy participation (AOR = 1.77; 95% CI: 1.37-2.30). DISCUSSION AND CONCLUSIONS: High rates of willingness to participate in a pharmacologic addiction treatment trial were observed in this setting. Importantly, high-risk drug and sexual activities were positively associated with a willingness to participate, which may suggest a desire for new treatment interventions among PWUD engaged in high-risk behavior. SCIENTIFIC SIGNIFICANCE: These results highlight the viability of studies seeking to enroll representative samples of PWUD engaged in high-risk drug use.

Health and social harms associated with crystal methamphetamine use among street-involved youth in a Canadian setting.

BACKGROUND AND OBJECTIVES: Despite recent increases in crystal methamphetamine use among high-risk populations such as street-involved youth, few prospective studies have examined the health and social outcomes associated with active crystal methamphetamine use. METHODS: We enrolled 1,019 street-involved youth in Vancouver, Canada, in a prospective cohort known as the at-risk youth study (ARYS). Participants were assessed semi-annually and a generalized estimating equation (GEE) logistic regression was used to identify factors independently associated with active crystal methamphetamine use. RESULTS: Among 1,019 participants recruited into ARYS between 2005 and 2012 the median follow up duration was 17 months, 320 (31.4%) participants were female and 454 (44.6%) had previously used crystal methamphetamine at baseline. In adjusted GEE analyses, active crystal methamphetamine use was independently associated with Caucasian ethnicity (adjusted odds ratio [AOR] = 1.37; 95% confidence interval [CI]: 1.04-1.81), homelessness (AOR = 1.34; 95% CI: 1.15-1.56), injection drug use (AOR = 3.40; 95% CI: 2.76-4.19), non-fatal overdose (AOR = 1.46; 95%CI: 1.07-2.00), being a victim of violence (AOR = 1.19; 95% CI: 1.02-1.38), involvement in sex work (AOR = 1.39; 95% CI: 1.03-1.86), and drug dealing (AOR = 1.60; 95% CI: 1.35-1.90). DISCUSSION AND CONCLUSIONS: Prevalence of crystal methamphetamine use was high in this setting and active use was independently associated with a range of serious health and social harms. SCIENTIFIC SIGNIFICANCE: Evidence-based strategies to prevent and treat crystal methamphetamine use are urgently needed.

Crystal methamphetamine initiation among street-involved youth.

BACKGROUND: Although many settings have recently documented a substantial increase in the use of methamphetamine-type stimulants, recent reviews have underscored the dearth of prospective studies that have examined risk factors associated with the initiation of crystal methamphetamine use. OBJECTIVES: Our objectives were to examine rates and risk factors for the initiation of crystal methamphetamine use in a cohort of street-involved youth. METHODS: Street-involved youth in Vancouver, Canada, were enrolled in a prospective cohort known as the At-Risk Youth Study (ARYS). A total of 205 crystal methamphetamine-naïve participants were assessed semi-annually and Cox regression analyses were used to identify factors independently associated with the initiation of crystal methamphetamine use. RESULTS: Among 205 youth prospectively followed from 2005 to 2012, the incidence density of crystal methamphetamine initiation was 12.2 per 100 person years. In Cox regression analyses, initiation of crystal methamphetamine use was independently associated with previous crack cocaine use (adjusted relative hazard [ARH] = 2.24 [95% CI: 1.20-4.20]) and recent drug dealing (ARH = 1.98 [95% CI: 1.05-3.71]). Those initiating methamphetamine were also more likely to report a recent nonfatal overdose (ARH = 3.63 [95% CI: 1.65-7.98]) and to be male (ARH = 2.12 [95% CI: 1.06-4.25]). CONCLUSIONS: We identified high rates of crystal methamphetamine initiation among this population. Males those involved in the drug trade, and those who used crack cocaine were more likely to initiate crystal methamphetamine use. Evidence-based strategies to prevent and treat crystal methamphetamine use are urgently needed.

Methadone maintenance therapy promotes initiation of antiretroviral therapy among injection drug users.

AIMS: Despite proven benefits of antiretroviral therapy (ART), many human immunodeficiency virus (HIV)-infected injection drug users (IDU) do not access treatment even in settings with free health care. We examined whether methadone maintenance therapy (MMT) increased initiation and adherence to ART among an IDU population with free health care. DESIGN: We examined prospectively a cohort of opioid-using antiretroviral-naive HIV-infected IDU and investigated factors associated with initiation of antiretroviral therapy as well as subsequent adherence. Factors associated independently with time to first initiation of antiretroviral therapy were modelled using Cox proportional hazards regression. FINDINGS: Between May 1996 and April 2008, 231 antiretroviral-naive HIV-infected opioid-using IDU were enrolled, among whom 152 (65.8%) initiated ART, for an incidence density of 30.5 [95% confidence interval (CI): 25.9-35.6] per 100 person-years. After adjustment for time-updated clinical characteristics and other potential confounders, use of MMT was associated independently with more rapid uptake of antiretroviral therapy [relative hazard = 1.62 (95% CI: 1.15-2.28); P = 0.006]. Those prescribed methadone also had higher rates of ART adherence after first antiretroviral initiation [odds ratio = 1.49 (95% CI: 1.07-2.08); P = 0.019]. CONCLUSION: These results demonstrate that MMT contributes to more rapid initiation and subsequent adherence to ART among opioid-using HIV-infected IDU. Addressing international barriers to the use and availability of methadone may increase dramatically uptake of HIV treatment among this population.

Where's the pump? Associating sporadic enteric disease with drinking water using a geographic information system, in British Columbia, Canada, 1996-2005.

We investigated whether risk of sporadic enteric disease differs by drinking water source and type using surveillance data and a geographic information system. We performed a cross-sectional analysis, at the individual level, that compared reported cases of enteric disease with drinking water source (surface or ground water) and type (municipal or private). We mapped 814 cases of campylobacteriosis, cryptosporidiosis, giardiasis, salmonellosis and verotoxigenic Escherichia coli infection, in a region of British Columbia, Canada, from 1996 to 2005, and determined the water source and type for each case's residence. Over the 10-year period, the risk of disease was 5.2 times higher for individuals living on land parcels serviced by private wells and 2.3 times higher for individuals living on land parcels serviced by the municipal surface/ground water mixed system, than the municipal ground water system. Rates of sporadic enteric disease potentially differ by drinking water source and type. Geographic information system technology and surveillance data are accessible to local public health authorities and used together are an efficient and affordable way to assess the role of drinking water in sporadic enteric disease.