Background
This study aimed to understand the combined effect of two opioid policies (mandatory prescription drug monitoring and restrictions on subsidised opioid prescribing, introduced between April and June 2020) on the rates of emergency department (ED) presentations and hospital admissions attributed to opioid and non-opioid related harms, in Victoria, Australia. We hypothesized that policies would reduce opioid harms, while resulting in unintended effects including increased non-opioid harm and increased presentations related to mental ill-health.
Method
General practice health records obtained with approval from three Primary Health Networks in Victoria collected via the POpulation Level Analysis and Reporting (POLAR) platform were linked with person-level data from three large hospital networks in Victoria, Australia. We identified a cohort of people prescribed opioids between April 2018 to March 2022 (n = 179,091). Propensity score matching was used to match each patient in the opioid group with one unique control. Interrupted time series analysis was used to examine changes in trends in the rates of ED presentations and hospital admissions due to a range of harms, including substance use (opioid and non-opioid) and mental ill-health following periods of policy change.
Results
Following an implementation window where two key opioid policies, mandatory prescription drug monitoring and restrictions on subsidised opioid prescribing, were introduced (between April and June 2020), opioid-related ED presentations and hospital admissions reduced, relative to trends observed prior to their implementation. A significant step change in the rates of non-opioid related ED presentations was seen among people prescribed opioids, compared to the control group (β = 11.1, 95%CI 1.7-20.5). We did not find an effect of these opioid policies on outcomes relating to mental health or self-harm.
Conclusion
When compared to a control group matched on age, gender, co-morbidity and socioeconomic status, we found ongoing reduced opioid-related ED presentations, combined with a short-term increase in ED presentations related to other substance use with no effects on ED presentations or hospital admissions related to mental ill-health following opioid policy implementation.