Objective To compare the risk of mortality among people with opioid use disorder on and off opioid agonist treatment (OAT) in a setting with a high prevalence of illicitly manufactured fentanyl and other potent synthetic opioids in the illicit drug supply. Design Population based retrospective cohort study. Setting Individual level linkage of five health administrative datasets capturing drug dispensations, hospital admissions, physician billing records, ambulatory care reports, and deaths in British Columbia, Canada. Participants 55 347 people with opioid use disorder who received OAT between 1 January 1996 and 30 September 2018. Main outcome measures All cause and cause specific crude mortality rates (per 1000 person years) to determine absolute risk of mortality and all cause age and sex standardised mortality ratios to determine relative risk of mortality compared with the general population. Mortality risk was calculated according to treatment status (on OAT, off OAT), time since starting and stopping treatment (1, 2, 3-4, 5-12, >12 weeks), and medication type (methadone, buprenorphine/naloxone). Adjusted risk ratios compared the relative risk of mortality on and off OAT over time as fentanyl became more prevalent in the illicit drug supply. Results 7030 (12.7%) of 55 347 OAT recipients died during follow-up. The all cause standardised mortality ratio was substantially lower on OAT (4.6, 95% confidence interval 4.4 to 4.8) than off OAT (9.7, 9.5 to 10.0). In a period of increasing prevalence of fentanyl, the relative risk of mortality off OAT was 2.1 (95% confidence interval 1.8 to 2.4) times higher than on OAT before the introduction of fentanyl, increasing to 3.4 (2.8 to 4.3) at the end of the study period (65% increase in relative risk). Conclusions Retention on OAT is associated with substantial reductions in the risk of mortality for people with opioid use disorder. The protective effect of OAT on mortality increased as fentanyl and other synthetic opioids became common in the illicit drug supply, whereas the risk of mortality remained high off OAT. As fentanyl becomes more widespread globally, these findings highlight the importance of interventions that improve retention on opioid agonist treatment and prevent recipients from stopping treatment.

Rural physicians showed an awareness and concern for alcohol consumption in their community, but they also reported difficulties referring patients for substance use treatment. Additional study is required to understand how to improve the continuity of care provided to persons with alcohol-related issues in rural British Columbia.

Background Being recently released from prison or discharged from hospital, or being dispensed opioids, benzodiazepines, or antipsychotics have been associated with an increased risk of fatal drug overdose. This study aimed to examine the association between these periods and non-fatal drug overdose using a within-person design.Methods In this self-controlled case series, we used data from the provincial health insurance client roster to identify a 20% random sample of residents (aged ≥10 years) in British Columbia, Canada between Jan 1, 2015, and Dec 31, 2017 (n=921 346). Individuals aged younger than 10 years as of Jan 1, 2015, or who did not have their sex recorded in the client roster were excluded. We used linked provincial health and correctional records to identify a cohort of individuals who had a non-fatal overdose resulting in medical care during this time period, and key exposures, including periods of incarceration, admission to hospital, emergency department care, and supply of medications for opioid use disorder (MOUD), opioids for pain (unrelated to MOUD), benzodiazepines, and antipsychotics. Using a self-controlled case series, we examined the association between the time periods during and after each of these exposures and the incidence of non-fatal overdose with case-only, conditional Poisson regression analysis. Sensitivity analyses included recurrent overdoses and pre-exposure risk periods. FindingsWe identified 4149 individuals who had a non-fatal overdose in 2015-17. Compared with unexposed periods (ie, all follow-up time that was not part of a designated risk period for each exposure), the incidence of non-fatal overdose was higher on the day of admission to prison (adjusted incidence rate ratio [aIRR] 2•76 [95% CI 1•51-5•04]), at 1-2 weeks (2•92 [2•37-3•61]), and 3-4 weeks (1•34 [1•01-1•78]) after release from prison, 1-2 weeks after discharge from hospital (1•35 [1•11-1•63]), when being dispensed opioids for pain (after ≥4 weeks) or benzodiazepines (entire use period), and from 3 weeks after discontinuing antipsychotics. The incidence of non-fatal overdose was reduced during use of MOUD (aIRRs ranging from 0•33 [0•26-0•42] to 0•41 [0•25-0•67]) and when in prison (0•12 [0•08-0•19]).Interpretation Expanding access to and increasing support for stable and long-term medication for the management of opioid use disorder, improving continuity of care when transitioning between service systems, and ensuring safe prescribing and medication monitoring processes for medications that reduce respiratory function (eg, benzodiazepines) could decrease the incidence of non-fatal overdose.

Background North American communities are severely impacted by the overdose crisis, particularly in British Columbia (BC), which has the highest toxic drug overdose death rate in Canada. Most fatal overdoses in BC occurred among individuals using alone and in private residences. This study aimed to assess prevalence and reasons for using drugs alone among people accessing harm reduction services in BC. Methods We recruited harm reduction supply distribution site clients from 22 communities across BC. Descriptive statistics and multivariable logistic regression were used to describe factors associated with using alone. Thematic analysis of free-text responses providing reasons for using alone were grouped with survey data and additional themes identified. Results Overall, 75.8% (n = 314) of the study sample (N = 414) reported using drugs alone within the last week. Those that reported using alone did not differ from those that did not by gender, age, urbanicity, or preferred drug use method. Among those that used alone, 73.2% (n = 230) used opioids, 76.8% (n = 241) used crystal meth, 41.4% (n = 130) used crack/cocaine, and 44.6% (n = 140) used alcohol in the past week. Polysubstance use involving stimulants, opioids, and/or benzodiazepines was reported by 68.5% (n = 215) of those that used alone. Additionally, 22.9% (n = 72) of those that used alone had experienced an opioid and/or stimulant overdose in the past 6 months. In a multivariable logistic regression model, having no regular housing and past week crack/cocaine use were associated with using alone (adjusted odds ratio (AOR): 2.27; 95% CI 1.20–4.27 and AOR: 2.10; 95% CI 1.15–3.82, respectively). The most common reason reported for using alone was convenience and comfort of using alone (44.3%). Additional reasons included: stigma/hiding drug use (14.0%); having no one around (11.7%); safety (9.6%); and not wanting to share drugs with others (8.6%). Conclusions Using drugs alone, particularly for convenience and comfort, is ubiquitous among people accessing harm reduction services. Overdose prevention measures that go beyond individual behaviour changes, including providing a safer supply of drugs and eliminating stigma, are paramount to mitigate harms. These interventions are especially necessary as emergence of coronavirus disease may further exacerbate unpredictability of illicit drug content and overdose risk.