Background Chronic non-cancer pain (CNCP) is common among frequent emergency department (ED) users, although factors underlying this association are unclear. This study estimated the association between sustained opioid use and frequent ED use among patients with CNCP.
Methods Retrospective cohort study using a Canadian provincial health insurer database (Régie d’Assurance Maladie du Québec). The database included adults with both ≥1 chronic condition and ≥ 1 ED visit in 2012 or 2013. Inclusion in the study further required a CNCP diagnosis, public drug insurance coverage and 1-year survival after the first ED visit in 2012 or 2013 (index visit). Multivariable logistic regression was used to derive ORs of frequent ED use (≥5 visits in the year following the index visit) subsequent to sustained opioid use (≥60 days opioids prescription within 90 days preceding the index visit), adjusting for important covariables.
Results From 576 688 patients in the database, 58 237 were included in the study. Of these, 4109 (7.1%) had received a sustained opioid prescription and 4735 (8.1%) were frequent ED users in the follow-up year. Sustained opioid use was not associated with frequent ED use in the multivariable model (OR: 1.06, 95% CI 0.94 to 1.19). Novel associated covariables were benzodiazepine prescription (OR: 1.21, 95% CI 1.12 to 1.30) and polypharmacy (OR: 1.23, 95% CI 1.13 to 1.34).
Conclusions Due to confounding by social and medical vulnerability, patients with CNCP with sustained opioid use appear to have a higher propensity for frequent ED use in unadjusted models. However, sustained opioid use was not associated with frequent ED use in these patients after adjustment.
- pain management
- primary health care
Data availability statement
Data may be obtained from a third party and are not publicly available. Data may be obtained from the Régie d’Assurance Maladie du Québec (RAMQ).
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Handling editor Gene Yong-Kwang Ong
Contributors FRH, AV, AL, YC, JC, AD and CH contributed substantially to the study conception, analysis and data interpretation. All authors have revised the attached article critically, approved of the version submitted for publication and agreed to be accountable for all aspects of the work. CH acts as guarantor for this study.
Funding This study was supported by the Fonds de recherche du Québec—Santé (FRQS) and the Département de médecine familiale et de médecine d’urgence de l’Université de Sherbrooke. For this research, François Racine-Hemmings was supported by scholarships from the Département de médecine familiale et de médecine d’urgence de l’Université de Sherbrooke and the Quebec SUPPORT Unit (Support for People and Patient-Oriented Research and Trials), an initiative funded by the Canadian Institutes of Health Research (CIHR) and the Ministère de la santé et des services sociaux du Québec and Fonds de recherche du Québec—Santé. Catherine Hudon was supported by a CIHR Embedded Clinician Researcher Salary Award. Alain Vanasse received grants for unrelated research from AstraZeneca Canada Inc. Anaïs Lacasse holds a Junior 2 research scholar from the FRQS in partnership with the Quebec SUPPORT Unit.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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