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

BMJ 2018; 362 doi: (Published 29 August 2018) Cite this as: BMJ 2018;362:k3207

Linked editorial

Opioid deaths in Ontario, Canada

  1. Tara Gomes, scientist1,
  2. Wayne Khuu, senior analyst2,
  3. Diana Martins, research program manager1,
  4. Mina Tadrous, research associate1,
  5. Muhammad M Mamdani, director3,
  6. J Michael Paterson, scientist2,
  7. David N Juurlink, scientist4
  1. 1Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, ON, Canada
  2. 2Institute for Clinical Evaluative Sciences, Toronto, ON, Canada
  3. 3Li Ka Shing Centre for Healthcare Analytics Research and Training at St. Michael’s Hospital, Toronto, ON, Canada
  4. 4The Sunnybrook Research Institute, Toronto, ON, Canada
  1. Correspondence to: T Gomes GomesT{at} @Tara_Gomes on Twitter)
  • Accepted 9 July 2018


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

Design Population based cohort study.

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

Participants All Ontarians who died of an opioid related cause.

Exposure Active opioid prescriptions, defined as those with a duration overlapping the date of death, and recent opioid prescriptions, defined as those dispensed in the 30 and 180 days preceding death. Postmortem toxicology results from the Drug and Drug/Alcohol Related Death database were used to characterise deaths on the basis of presence of prescribed and non-prescribed (that is, diverted or illicit) opioids, overall and stratified by year and age.

Results 2833 opioid related deaths occurred. An active opioid prescription on the date of death was relatively common but declined slightly throughout the study period (38.2% (241/631) in 2013 and 32.5% (278/855) in 2016; P for trend=0.03). Older people and women were relatively more likely to have an active opioid prescription at time of death. In 2016, 46% (169/364) of people aged 45-64 had an active opioid prescription compared with only 12% (8/69) among those aged 24 or younger (P for trend<0.001). Similarly, 46% (124/272) of women had an active opioid prescription at time of death compared with 26.4% (154/583) of men (P<0.001). Among people with active opioid prescriptions at time of death, 37.8% (375/993) also had evidence of a non-prescribed opioid on postmortem toxicology. By 2016, the non-prescribed opioid most commonly identified after death was fentanyl (41%; 47 of 115 cases). Among people without an active opioid prescription at time of death, fentanyl was detected in 20% (78/390) of deaths in 2013, increasing to 47.5% (274/577) by 2016 (P<0.001).

Conclusions 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 multifactorial approach to this problem that considers both the prescribed and illicit opioid environments.


  • Contributors: TG, WK, DM, MT, MMM, JMP, and DNJ were involved in the conception and design of the study. TG and WK acquired the data. TG, WK, DM, MT, MMM, JMP, and DNJ analysed and interpreted the data. TG drafted the article. WK, DM, MT, MMM, JMP, and DNJ revised the article critically for important intellectual content. TG, WK, DM, MT, MMM, JMP, and DNJ gave final approval of the version to be published. All authors had access to the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. TG attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted. She is the guarantor.

  • Funding: This study was supported by a grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC; grant #06673) and the Canadian Institutes for Health Research (grant #153070). It was also supported by the Institute for Clinical Evaluative Sciences (ICES), a non-profit research institute sponsored by the Ontario MOHLTC. The opinions, results, and conclusions reported in this paper are those of the authors and are independent from the funding sources. No endorsement by ICES or the Ontario MOHLTC is intended or should be inferred.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available on request from the corresponding author) and declare: TG received grant funding from the Ontario Ministry of Health and Long-Term Care to support this work; MMM has received personal fees from Celgene, NovoNordisk, and Allergan outside the submitted work; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The study protocol was approved by the research ethics board of Sunnybrook Health Sciences Centre, Toronto, Ontario.

  • Data sharing: The dataset from this study is held securely in coded form at the Institute for Clinical Evaluative Sciences (ICES). Although data sharing agreements prohibit ICES from making the dataset publicly available, access may be granted to those who meet pre-specified criteria for confidential access, available at

  • Transparency statement: The lead author (the manuscript’s guarantor) affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

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