Opioid agonist therapy and mortality among First Nations and other residents with concurrent alcohol use disorder in British Columbia, Canada: A population-based cohort study.

BACKGROUND: Despite the prevalence of alcohol use among people with opioid use disorder (PWOUD) engaged in opioid agonist therapy (OAT), clinical care guidance for concurrent alcohol use disorder (AUD) and OUD is scarce. We assessed the prevalence and risk of mortality for concurrent AUD among PWOUD who accessed OAT in British Columbia (BC). METHODS: Data were obtained from six linked population-level health administrative datasets to identify PWOUD from January 1996 to March 2020. All-cause age and sex standardized mortality ratios (SMR) were calculated to determine the mortality risk by OAT status (on vs. discontinued), stratified by First Nations and other residents with concurrent AUD and OUD. Adjusted risk ratios compared the relative risk of mortality by AUD status (AUD detected vs. not) among First Nations and other residents. RESULTS: We identified 62,110 PWOUD who received OAT, including 6305 (10.2%) First Nations. OAT substantially lowered the SMR among First Nations (SMR=6.6, 95% CI: 5.4-8.1) and other residents (SMR=6.6; 95% CI: 6.2-7.0) with concurrent AUD and OUD, compared to those who discontinued (SMR=22.7, 95% CI: 20.4-25.1, SMR=17.5, 95% CI: 16.8-18.2 respectively). The risk of mortality was 1.9 (95% CI: 1.6-2.2) times higher for First Nations and 2.0 (95% CI: 1.8-2.2) times higher for other residents with concurrent OUD and AUD compared to those without an indication of AUD. CONCLUSIONS: The protective effect of OAT remained despite the presence of a concurrent AUD among both First Nations and other residents with OUD. Findings have implications for clinical care management of concurrent disorders.

Association between toxic drug events and encephalopathy in British Columbia, Canada: a cross-sectional analysis.

BACKGROUND: Encephalopathy can occur from a non-fatal toxic drug event (overdose) which results in a partial or complete loss of oxygen to the brain, or due to long-term substance use issues. It can be categorized as a non-traumatic acquired brain injury or toxic encephalopathy. In the context of the drug toxicity crisis in British Columbia (BC), Canada, measuring the co-occurrence of encephalopathy and drug toxicity is challenging due to lack of standardized screening. We aimed to estimate the prevalence of encephalopathy among people who experienced a toxic drug event and examine the association between toxic drug events and encephalopathy. METHODS: Using a 20% random sample of BC residents from administrative health data, we conducted a cross-sectional analysis. Toxic drug events were identified using the BC Provincial Overdose Cohort definition and encephalopathy was identified using ICD codes from hospitalization, emergency department, and primary care records between January 1st 2015 and December 31st 2019. Unadjusted and adjusted log-binomial regression models were employed to estimate the risk of encephalopathy among people who had a toxic drug event compared to people who did not experience a toxic drug event. RESULTS: Among people with encephalopathy, 14.6% (n = 54) had one or more drug toxicity events between 2015 and 2019. After adjusting for sex, age, and mental illness, people who experienced drug toxicity were 15.3 times (95% CI = 11.3, 20.7) more likely to have encephalopathy compared to people who did not experience a drug toxicity event. People who were 40 years and older, male, and had a mental illness were at increased risk of encephalopathy. CONCLUSIONS: There is a need for collaboration between community members, health care providers, and key stakeholders to develop a standardized approach to define, screen, and detect neurocognitive injury related to drug toxicity.

Take-home drug checking as a novel harm reduction strategy in British Columbia, Canada.

BACKGROUND: Drug checking is a harm reduction strategy used to identify components of illicitly obtained drugs, including adulterants, to prevent overdose. This study evaluated the distribution of take-home fentanyl test strips to people who use drugs (PWUD) in British Columbia, Canada. The primary aim was to assess if the detection of fentanyl in opioid samples was concordant between a take-home model and testing by trained drug checking staff. METHODS: Take-home fentanyl test strips were distributed at ten sites providing drug checking services from April to July 2019. The fentanyl positivity of the aggregate take-home and on-site drug checking groups were compared by class of substance tested. An administered survey assessed acceptability and behaviour change. RESULTS: 1680 take-home results were obtained from 218 unique participants; 68% of samples (n=1142) were identified as opioids and 23% (n=382) were stimulant samples. During this period, 852 samples were tested using on-site drug checking. The fentanyl positivity of opioid samples was 90.0% for take-home samples and 89.1% for on-site samples (Difference 0.8% (95% CI -2.3% to 3.9%)). These results were not affected by previous experience with test strips. Fentanyl positivity of stimulants in the take-home group was higher than on-site (24.7% vs. 3.2%), but the study was underpowered to conduct statistical analysis on this sub-group. When fentanyl was detected, 27% of individuals reported behaviour change that was considered safer/positive. Greater than 95% of participants stated they would use fentanyl test strips again. CONCLUSIONS: Take-home fentanyl test strips used by PWUD on opioid samples can provide similar results to formal drug checking services and are a viable addition to existing overdose prevention strategies. Use of this strategy for detection of fentanyl in stimulant samples requires further evaluation. This intervention was well accepted and in some participants was associated with positive behaviour change.

Risk of overdose-related death for people with a history of incarceration.

BACKGROUND AND AIMS: Reported associations between previous incarceration and the risk of overdose-related death are substantially heterogeneous, and previous studies are limited by an inability to control for confounding factors in risk assessment. This study investigated the associations of overdose-related death with previous incarceration and the number or cumulative duration of previous incarcerations, and individual or neighborhood characteristics that may potentially modify the associations. DESIGN AND SETTING: A cohort study using a 20% random sample of residents in British Columbia, Canada. PARTICIPANTS: A total of 765 690 people aged 23 years or older at baseline as of 1 January 2015. Mean age was 50 years; 49% were males. MEASUREMENTS: Previous incarcerations that occurred during the 5-year exposure period (January 2010 to December 2014) were identified using provincial incarceration records. Overdose-related deaths that occurred during the 3-year follow-up period (January 2015 to December 2017) were identified using linked administrative health data. Baseline individual and neighborhood characteristics were retrieved from the provincial health insurance data. FINDINGS: In the cohort, 5743 people had an incarceration history during the exposure period, and 634 people died from drug overdose during the follow-up period. The mortality rate was 897 and 22 per 100 000 person-years for people who did and did not have an incarceration history, respectively. After adjusting for baseline individual and neighborhood characteristics (without any interaction term), people who had an incarceration history were 4.04 times (95% confidence interval 3.23-5.06) more likely to die from drug overdose compared with people without an incarceration history. The association was stronger for females, people without diagnoses of substance use disorder and people without dispensation of opioids for pain or benzodiazepines (P < 0.001 for each interaction term). There was no discernible linear trend between the number or cumulative duration of previous incarcerations and the risk of overdose-related death. CONCLUSIONS: Previous incarceration appears to be a major risk factor for overdose-related death.