Sentinel surveillance of suspected opioid-related poisonings and injuries: trends and context derived from the electronic Canadian Hospitals Injury Reporting and Prevention Program, March 2011 to June 2017.

INTRODUCTION: The opioid epidemic is currently a major public health problem in Canada. As such, knowledge of upstream risk factors associated with opioid use is needed to inform injury prevention, health promotion and harm reduction efforts.

METHODS: We analyzed data extracted from 11 pediatric and 6 general hospital emergency departments (EDs) as part of the electronic Canadian Hospitals Injury Reporting and Prevention Program (eCHIRPP) from March 2011 to June 2017. We identified suspected opioid-related injuries using search strings and manually verified them. We computed age-adjusted and sex-stratified proportionate injury ratios (PIRs) and 95% confidence intervals (CIs) to compare opioid-related injuries to all injuries in eCHIRPP. Negative binomial regression was used to determine trends over time. We conducted qualitative analyses of narratives to identify common themes across life stages.

RESULTS: Between March 2011 and June 2017, 583 suspected opioid-related poisoning/ injury cases were identified from eCHIRPP. Most of the cases were females (55%). Many of the injuries occurred in patients' own homes (51%). Forty-five percent of the injuries were intentional self-harm. Among children (aged 1-9 years), most injuries were caused by inadvertent consumption of opioids left unattended. Among youth (aged 10-19 years) and adults (aged 20-49 years), opioid use was associated with underlying mental illness. Overall, the average annual percent change (AAPC) in the rate of injuries (per 100 000 eCHIRPP cases) has been increasing since 2012 (AAPC = 11.9%, p < .05). The increase is particularly evident for males (AAPC = 16.3%, p < .05). Compared to other injuries, people with suspected opioid-related injuries were more likely to be admitted to hospital (PIR = 5.3, 95% CI: 4.6-6.2).

CONCLUSION: The upstream determinants of opioid-related injuries are complex and likely vary by subpopulations. Therefore, continued monitoring of risk factors is important in providing the evidence necessary to prevent future overdoses and deaths.