Opioid-related mortality appears to be increasing in Canada. The authors examined the true extent of the problem and the impact of the introduction of long-acting oxycodone.

The authors examined trends in the prescribing of opioid analgesics in the province of Ontario from 1991 to 2007. They reviewed all deaths related to opioid use between 1991 and 2004. They linked 3,271 of these deaths to administrative data to examine the patients’ use of health care services before death. Using time-series analysis, the investigators determined whether the addition of long-acting oxycodone to the provincial drug formulary in January 2000 was associated with an increase in opioid-related mortality.

From 1991 to 2007, annual prescriptions for opioids in creased from 458 to 591 per 1,000 individuals. Opioidrelated deaths doubled, from 13.7 per million in 1991 to 27.2 per million in 2004. Prescriptions of oxycodone increased by 850% between 1991 and 2007. The addition of long-acting oxycodone to the drug formulary was associated with a 5-fold increase in oxycodone-related mortality (p < 0.01) and a 41% increase in overall opioid-related mortality (p = 0.02). The manner of death was deemed unintentional by the coroner in 54.2% and undetermined in 21.9% of cases. Use of health care services in the month before death was common: for example, of the 3,066 patients for whom data on physician visits were available, 66.4% had visited a physician in the month before death; of the 1,095 patients for whom individual-level prescribing data were available, 56.1% had filled a prescription for an opioid in the month before death.

Opioid-related deaths in Ontario have increased markedly since 1991. A significant portion of the increase was associated with the addition of long-acting oxycodone to the provincial drug formulary. Most of the deaths were deemed unintentional. The frequency of visits to a physician and prescriptions for opioids in the month before death suggests a missed opportunity for prevention.