Contributions of prescribed and non-prescribed opioids to opioid-related deaths: a population-based cohort study in Ontario, Canada

Importance — There is an urgent need for timely data on the relative contributions of prescribed, diverted and illicit opioids to opioid-related deaths.

Objective — To describe the contributions of prescribed and non-prescribed opioids to opioid-related deaths.

Design — Population-based cohort study

Setting — Ontario, Canada, from January 1, 2013 to December 31, 2016.

Participants — All Ontarians who died of an opioid-related cause.

Exposure — We defined active opioid prescriptions as those with a duration overlapping the date of death, and recent opioid prescriptions as those dispensed in the 30 and 180 days preceding death. We used post-mortem toxicology results from the Drug and Drug/Alcohol Related Death database to characterize deaths on the basis of presence of prescribed and non-prescribed (i.e. diverted or illicit) opioids, overall and stratified by year and age.

Results — We studied 2,833 opioid-related deaths. An active opioid prescription on the date of death was relatively common, but declined slightly throughout the study period (38.2% in 2013 and 32.5% in 2016; p-value for trend=0.03). Older individuals and women were relatively more likely to have an active opioid prescription at time of death. In 2016, 46.4% of those aged 45 to 64 had an active opioid prescription compared with only 11.6% among those aged 24 or younger (p-value for trend <.001). Similarly, 45.6% of women had an active opioid prescription at time of death compared to 26.4% of men (p<.001). Among people with active opioid prescriptions at time of death, 37.8% also had evidence of a non-prescribed opioid on postmortem toxicology. By 2016, the most commonly identified non-prescribed opioid post-mortem was fentanyl (40.4% of cases). Among those without an active opioid prescription at time of death, fentanyl was detected in 20% of deaths in 2013, increasing to 47.5% by 2016 (p<0.001).

Conclusions and Relevance — Prescribed, diverted and illicit opioids all play an important role in opioid-related deaths. Although more than half of all opioid-related deaths still involved prescription drugs (either dispensed or diverted) in 2016, the increased rate of deaths involving fentanyl between 2015 and 2016 is concerning and suggests the need for a multi-factorial approach to this issue that considers both the prescribed and illicit opioid environment.