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Factors associated with early opioid dispensing compared with NSAID and muscle relaxant dispensing after a work-related low back injury
  1. Nancy Carnide1,
  2. Sheilah Hogg-Johnson1,2,3,
  3. Pierre Côté2,3,4,5,
  4. Mieke Koehoorn1,6,
  5. Andrea D Furlan1,7,8
  1. 1 Institute for Work and Health, Toronto, Ontario, Canada
  2. 2 Research & Innovation, Canadian Memorial Chiropractic College, Toronto, Ontario, Canada
  3. 3 Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
  4. 4 Faculty of Health Sciences, Ontario Tech University, Oshawa, Ontario, Canada
  5. 5 Centre for Disability Prevention and Rehabilitation, Ontario Tech University, Oshawa, Ontario, Canada
  6. 6 School of Population and Public Health, The University of British Columbia, Vancouver, British Columbia, Canada
  7. 7 KITE, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada
  8. 8 Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
  1. Correspondence to Dr Nancy Carnide, Institute for Work and Health, Toronto, ON M5G 2E9, Canada; ncarnide{at}


Objectives The objective of this historical cohort study was to determine the claimant and prescriber factors associated with receiving opioids at first postinjury dispense compared with non-steroidal anti-inflammatory drugs (NSAIDs) and skeletal muscle relaxants (SMRs) in a sample of workers’ compensation claimants with low back pain (LBP) claims between 1998 and 2009 in British Columbia, Canada.

Methods Administrative workers’ compensation, prescription and healthcare data were linked. The association between claimant factors (sociodemographics, occupation, diagnosis, comorbidities, pre-injury prescriptions and healthcare) and prescriber factors (sex, birth year, specialty) with drug class(es) at first dispense (opioids vs NSAIDs/SMRs) was examined with multilevel multinomial logistic regression.

Results Increasing days supplied with opioids in the previous year was associated with increased odds of receiving opioids only (1–14 days OR 1.62, 95% CI 1.51 to 1.75; ≥15 days OR 5.12, 95% CI 4.65 to 5.64) and opioids with NSAIDs/SMRs (1–14 days OR 1.49, 95% CI 1.39 to 1.60; ≥15 days OR 2.82, 95% CI 2.56 to 3.12). Other significant claimant factors included: pre-injury dispenses for NSAIDs, SMRs, antidepressants, anticonvulsants and sedative-hypnotics/anxiolytics; International Statistical Classification of Diseases and Related Health Problems, 9th Revision diagnosis; various pre-existing comorbidities; prior physician visits and hospitalisations; and year of injury, age, sex, health authority and occupation. Prescribers accounted for 25%–36% of the variability in the drug class(es) received, but prescriber sex, specialty and birth year did not explain observed between-prescriber variation.

Conclusions During this period in the opioid crisis, early postinjury dispensing was multifactorial, with several claimant factors associated with receiving opioids at first prescription. Prescriber variation in drug class choice appears particularly important, but was not explained by basic prescriber characteristics.

  • clinical medicine
  • occupational health practice
  • back disorders

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  • Contributors All authors contributed to study concept and design, as well as acquisition of funding. NC and SH-J were responsible for the data acquisition process. NC led all data analyses and drafted the manuscript. All authors contributed to the interpretation of the results and critically reviewed and revised the manuscript for important intellectual content. All authors approved this final version. NC had full access to the study data and takes responsibility for the integrity of the data and accuracy of the analyses.

  • Funding This research was supported with funding from WorkSafeBC through the Research at Work programme (fund number RS2011-OG12) and from the Canadian Institutes of Health Research (CIHR) Open Operating Grant programme (fund number 115032). NC was supported by a CIHR Vanier Canada Graduate Scholarship during the course of this work. The research was undertaken, in part, thanks to funding from the CIHR Canada Research Chairs programme to Pierre Côté (Canada Research Chair in Disability Prevention and Rehabilitation) and Mieke Koehoorn (Canada Research Chair in Gender, Work and Health) and the CIHR New Investigator Award programme to AF. MK receives infrastructure funding from WorkSafeBC (the provincial workers’ compensation system in British Columbia, Canada) via a formal research agreement between the University of British Columbia and WorkSafeBC. The Institute for Work & Health receives infrastructure support from Ontario’s Ministry of Labour, Training and Skills Development.

  • Disclaimer All inferences, opinions and conclusions drawn in this report are those of the authors, and do not reflect the opinions or policies of the Data Steward(s) or the Province of Ontario.

  • Competing interests AF developed the Opioid Manager, a point-of-care tool that distils information from the Canadian Guideline for Safe and Effective Use of Opioids for Chronic Non-Cancer Pain. This app, available on iTunes for US$9.99, is owned by the University Health Network and all revenues are used to invest in the continued maintenance of the app itself.

  • Patient consent for publication Not required.

  • Ethics approval This study was approved by the University of Toronto Health Sciences Research Ethics Board (protocol reference number 26885).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data may be obtained from a third party and are not publicly available. These data are held by Population Data BC. Datasets are available to researchers through a data access request to Population Data BC, with appropriate approvals by the relevant data stewards. Due to privacy agreements, data used in this study cannot be shared by the researchers.