Assessing the impact of the slow-release oral morphine drug shortages in Ontario, Canada: A population-based time series analysis.

BACKGROUND: Slow-release oral morphine (SROM) is used to manage pain, and as opioid agonist treatment (OAT). Between 2017 and 2021 in Canada, several drug shortages occurred for Kadian© (SROM-24). The purpose of this study was to evaluate the impact of these shortages on people's ability to remain on this medication. METHODS: We conducted a retrospective population-based time series analysis of SROM-24 dispensed between January 1, 2014, and December 31, 2021, in Ontario, Canada. Using interventional autoregressive integrated moving average models (ARIMA) models, we evaluated the association between SROM-24 drug shortages and treatment discontinuation. Analyses were also stratified by the SROM-24 indication (pain or OAT). RESULTS: We identified 22,479 SROM-24 recipients, of which one-third (33.9%) were aged 65 or above and just over half (51.9%) were female. In our primary analysis of monthly SROM-24 discontinuation, we observed a significant sustained monthly increase following the shortages in November 2019 (+0.29%/month; 95% CI: 0.16%, 0.43%; p < .001) with significant sudden, temporary changes following the shortages in March 2020 (+2.00%; 95% CI: 0.95%, 3.05%; p < .001), July 2021 (+3.53%; 95% CI: 2.20%, 4.86%; p < .001), and August 2021 (+4.98%; 95% CI: 3.49%, 6.47%; p < .001). Similar results were observed in our stratified analyses, with sustained high rates of discontinuation among people accessing SROM-24 as OAT. CONCLUSIONS: The SROM-24 shortages resulted in significant treatment disruptions across all recipients. These findings have important implications for those with few treatment alternatives, including people using SROM-24 as OAT who are at risk of adverse outcomes following treatment disruptions.