(002) Assessing The Impact of the Slow-Release Oral Morphine Drug Shortages in Ontario: a Population-Based Time Series Analysis

Publication Number: 666

Background: Slow-release oral morphine (SROM) is used to manage pain, and increasingly as a novel form of opioid agonist treatment (OAT). Between 2017 and 2021, several drug shortages occurred for the 24-hour formulation of Kadian© (SROM-24) due to manufacturing issues and increased demand. Currently, little is known about the impact of these shortages on access to this medication.

Objectives: To evaluate the impact of the SROM-24 drug shortages on people accessing this medication, including whether there were treatment disruptions.

Methods: We conducted a retrospective population-based time series analysis of people dispensed SROM-24 between January 1, 2014, and December 31, 2021, in Ontario, Canada. All Ontario residents aged ≥18 who were dispensed SROM-24 over the study period were included in the study cohort. Those without a valid Ontario health card number were excluded to allow for data linkage. We used administrative health data housed at ICES, with all dispensed SROM-24 prescriptions identified through the Narcotics Monitoring System. We used interventional autoregressive integrated moving average (ARIMA) models with ramp and pulse functions to evaluate the impact of the SROM-24 drug shortages on our primary measure of monthly treatment discontinuation. All analyses were stratified by people using SROM-24 as OAT and to manage pain.

Results: Over the study period we identified 22,479 SROM-24 recipients (mean age: 56.4 years; 51.9% female). Among these individuals, 33.7% resided in neighbourhoods in the lowest quintile of income and 84.9% in urban areas. In our analysis, monthly overall SROM-24 discontinuation remained relatively stable until the initial shortages in November 2019 which led to a significant ramp increase in treatment discontinuation (+0.3% per month, 95% confidence interval [CI]: 0.2%, 0.4%, p <.001). This was followed by significant pulse increases in discontinuation following the shortages in March 2020 (+2.0%, 95% CI: 1.0%, 3.1%, p <.001), July 2021 (+3.5%, 95% CI: 2.2%, 4.9%, p <.001) and August 2021 (+5.0%, 95% CI: 3.5%, 6.5%, p <.001). Similar results were observed in our stratified analyses, although more sustained high rates of discontinuation were found among people accessing SROM-24 for OAT.

Conclusions: We found that the numerous SROM-24 drug shortages had a significant impact on treatment discontinuation among all recipients. These findings have important implications for those who have fewer alternative treatment options, such as those using SROM-24 as OAT who are at an increased risk of adverse clinical outcomes following abrupt treatment disruptions.