Multi-drug involvement in apparent opioid and stimulant toxicity deaths in Canada from 2018 to 2023: Understanding the data

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Methods

Data sources

Record-level data on apparent opioid or stimulant toxicity deaths between 2018 and 2023 were obtained from the Public Health Agency of Canada's opioid- and stimulant-related harms surveillance system for up to ten provinces and territories (P/Ts) (depending on year), which accounts for 45% of apparent opioid toxicity deaths (AOTDs) and 64% of apparent stimulant toxicity deaths (ASTDs) in Canada ^{Reference 1}. Notably, record-level data were not available from British Columbia, Alberta or Manitoba for any year.

Data includes all deaths with completed or ongoing investigations and where manner of death is classified as accident, suicide, or undetermined. Deaths are captured under 2 broad substance classes: opioids and stimulants. Within these classes, the involvement of 3 specific substances (fentanyl, cocaine and methamphetamine) and 4 substance groups (fentanyl analogues, non-fentanyl opioids, other stimulants and other psychoactive substances) are reported. As a result, a single death may include up to 7 substances and substance groups.

In some cases, toxicology testing confirmed the presence of opioids or stimulants but did not specify the substance(s) involved. These cases are presented in the results under indicators labeled 'no granularity'. Deaths with unclear or invalid substance involvement information were excluded from the analysis (4% of deaths). Refer to Table A in the Technical notes for more information on data availability.

Definitions

• An opioid or stimulant toxicity death: A death caused by toxicity or poisoning resulting from substance use, where 1 or more of the substances involved (detected and/or contributed) is an opioid or a stimulant, regardless of how it was obtained (e.g., illegally or through personal prescription). Other psychoactive substances may also be involved.
  • Apparent opioid toxicity death (AOTD): where 1 or more of the substances involved was an opioid.
  • Apparent stimulant toxicity death (ASTD): where 1 or more of the substances involved was a stimulant.
• Other psychoactive substances: A broad category of substances, which may include alcohol, benzodiazepines, gabapentinoids, ketamine, LSD, PCP, psilocin, W-18 and Z-drugs. This definition varies across jurisdictions.
• Multi-drug toxicity: The involvement (detection or contribution) of two or more opioids, stimulants and/or other psychoactive substances or substance groups in a substance-related toxicity death.
• Substance information:
  • Substance class: A broad category of substances with similar pharmacological effects, classified as either opioids or stimulants in this report.
  • Substance group: A collection of substances within a substance class that share similar chemical structures or effects. To note, substances that do not fit into a defined group are categorized under the "other psychoactive substances" group.
  • Substance: A specific drug or compound that belongs to a substance group and is classified under the opioid or stimulant substance class.

Statistical analysis

Descriptive analysis was used to explore all possible combinations of substance groups, where 2 or more of the following were involved in deaths:

• opioids (fentanyl, fentanyl analogues, non-fentanyl opioids)
• stimulants (cocaine, methamphetamine, other stimulants)
• other psychoactive substances.

Groupings were informed by both toxicological patterns in the unregulated drug supply and the frequency with which substances appear in toxicity deaths. Fentanyl and its analogs were analyzed separately given their predominance. Non-fentanyl opioids were grouped together due to lower detection rates and a wider range of potencies. Similarly, cocaine and methamphetamine were separated from other stimulants due to their central role in deaths. Specific substances in each group are outlined in Table C.

Substance and substance group combinations were further explored by year, age, sex, and jurisdiction. The most common substances and combinations (present in at least 5% of deaths in any year) were selected for presentation to illustrate key trends. Percentages were calculated with denominators specific to substances and substance group combinations and therefore may not add up to 100% due to varying denominators. Reports with unknown sex and age were excluded from sex- and age-specific analyses but were included in overall counts. Small counts (<5) were suppressed to protect privacy and prevent reidentification. The data analysis was conducted using SAS Enterprise Guide (EG) version 9.4 and RStudio 2022.12.0.

Technical notes

Data limitations, including reporting, substance, and death classification differences.

Regional reporting

• Approximately 75% of provinces and territories provide record-level data; however, some of these P/Ts were not able to report in this format for the full analysis period (2018 to 2023). Data from provinces and territories that do not provide record-level data, were excluded from the analysis resulting in a non-national representation, as these account for 55% of apparent opioid toxicity death (AOTDs) and 34% of apparent stimulant toxicity deaths (ASTDs), over the 5-year period. Therefore, case counts may appear different from totals published in the national public health Infobase page on Opioid- and Stimulant-related Harms in Canada^{Reference 1}
• Percentages for each substance combination may not sum up to 100% due to differences in denominators used to calculate the proportion of deaths for each substance combination, as not all P/Ts were able to submit data for every combination. Consequently, the percentages should be interpreted as the proportion of deaths involving each specific substance combination relative to the total number of deaths in the participating P/Ts with available data for that particular combination.
• Sensitivity analyses showed that including all P/Ts in denominators or adjusting for substance-specific deaths resulted in minor differences (0.5–5%) in rates and percentages, with consistent overall trends. This confirms that observed patterns across demographics remain consistent, regardless of minor variations in reporting capabilities. In the interest of presenting the most accurate and contextually appropriate data, percentages were calculated over deaths with varying P/T denominators to account for variations in data availability (refer to Table B).
• Provincial and territorial differences exist in the type of data reported. In addition, more recent data are incomplete and subject to change as investigations are completed.

Substance reporting

• Data on individual substances within the "other psychoactive substances" group were not available.
• Details on specific substances detected or attributed to the death may only be available for completed investigations. Some provinces and territories may not be able to make this distinction at the time of reporting. Some toxicology results specifying the substances involved in the deaths were not available at the time of data submission. Thus, some deaths may or may not include opioids or other substances.
• The surveillance data used for this project do not specify the individual substances within the broader substance types (I.e. fentanyl analogues, non-fentanyl opioids, other stimulants, and other psychoactive substances). As such, there may be instances where more than two substances are involved in a death in a single category. The data presented will report on the minimum number of substances involved in the deaths (I.e., includes "at least one" fentanyl analogue, non-fentanyl opioid, other stimulant or psychoactive substance).

Death classification

• Given provincial and territorial differences in death classification methods, the term "involving" includes deaths where the substance was either detected and/or contributed to the death. Substances detected through toxicology testing may or may not have contributed to the death. Attribution of the death to the substance is based on investigation by a coroner or medical examiner.
• This study only captures minimum proportions of multi-drug deaths as it only accounts for opioids and stimulants involved in a death, with or without the involvement of other psychoactive substances. This study does not report on all substance-related acute toxicity deaths (e.g., alcohol), nor where deaths involved a psychoactive substance but opioids or stimulants were not one of the substances contributed to death.

Table A: Data availability by province or territory

Table B: Substance and substance group combination-based denominator inclusions and exclusions across study years

Note(s): All Reporting Provinces = SK, ON, QC, NB, NS, PEI, NL, NT, NU, YT

Table C: Types of collected and reported opioids and stimulants

References

Acknowledgements

We recognize that the data used in this report may represent stories of pain, grief and trauma. This report cannot adequately reflect the burden borne by people in Canada. We acknowledge all those impacted by substance use and those who work to save lives and reduce substance-related harms on individuals and communities.

We also express our gratitude to our partners and collaborators who provided the data on toxicity deaths and insights on the findings. This includes the provincial and territorial offices of chief coroners and chief medical examiners, provincial and territorial public health and health care partners, and persons with lived and living experience. Additionally, we extend our thanks to all reviewers for their valuable contributions to the report and constructive feedback.

Suggested citation

Multi-Drug Involvement in Apparent Opioid and Stimulant Toxicity Deaths in Canada. Public Health Agency of Canada, Health Infobase.