New opioid prescription claims and their clinical indications: results from health administrative data in Quebec, Canada, over 14 years

Objectives: Describe new opioid prescription claims, their clinical indications and annual trends among opioid naïve adults covered by the Quebec's public drug insurance plan (QPDIP) for the fiscal years 2006/2007-2019/2020.

Design and setting: A retrospective observational study was conducted using data collected between 2006/2007 and 2019/2020 within the Quebec Integrated Chronic Disease Surveillance System, a linkage administrative data.

Participants: A cohort of opioid naïve adults and new opioid users was created for each study year (median number=2 263 380 and 168 183, respectively, over study period).

Intervention: No.

Main outcome measure and analyses: A new opioid prescription was defined as the first opioid prescription claimed by an opioid naïve adult during a given fiscal year. The annual incidence proportion for each year was then calculated and standardised for age. A hierarchical algorithm was built to identify the most likely clinical indication for this prescription. Descriptive and trend analyses were performed.

Results: There was a 1.7% decrease of age-standardised annual incidence proportion during the study period, from 7.5% in 2006/2007 to 5.8% in 2019/2020. The decrease was highest after 2016/2017, reaching 5.5% annual percentage change. Median daily dose and days' supply decreased from 27 to 25 morphine milligram equivalent/day and from 5 to 4 days between 2006/2007 and 2019/2020, respectively. Between 2006/2007 and 2019/2020, these prescriptions' most likely clinical indications increased for cancer pain from 34% to 48%, for surgical pain from 31% to 36% and for dental pain from 9% to 11%. Inversely, the musculoskeletal pain decreased from 13% to 2%. There was good consistency between the clinical indications identified by the algorithm and prescriber's specialty or user's characteristics.

Conclusions: New opioid prescription claims (incidence, dose and days' supply) decreased slightly over the last 14 years among QPDIP enrollees, especially after 2016/2017. Non-surgical and non-cancer pain became less common as their clinical indication.