Cases are people included in the Cohort who had a drug-related overdose since January 1, 2015. This period was the beginning of the rapid rise in illicit drug overdoses and deaths in B.C. 

An overdose event is defined by any of the following: 

• Administration of the opioid antagonist naloxone by paramedics
• A call to the Drug and Poison Information Center about an opioid-related event
• Physician-diagnosed opioid overdose at an emergency department
• Coroner-determined illicit drug toxicity death
• A visit to a hospital, emergency department, or physician with an associated overdose diagnosis code
• Vital Statistics overdose-related death.
  

Overdose events can show up in several datasets. For example, an overdose record may be in ambulance, emergency, and hospital datasets. These events are grouped to prevent over-counting of overdoses.

Controls

Controls are people used as a comparison group for the Cohort. The Control group is selected from a 20% random sample of the B.C. population. Like cases, health and prescribing histories are available for this group. 

A matched control group is also available. Previous Cohort analyses have matched people on birth year, sex, and Local Health Area of residence. 

Potential Uses

Knowledge Updates & Analyses that Support the Overdose Response

• There is a high prevalence of brain injury among people who had an overdose
  
• The risk of severe COVID-19 complications is high among people who had an overdose
  
• There is an increasing proportion of people declining transportation to the hospital by paramedics following an overdose event
  

Research Papers

• Patterns and history of prescription drug use among opioid-related drug overdose
• Risk of overdose‐related death for people with a history of incarceration