A study from Ontario, Canada, has found that prescribed, diverted and illicit opioids all play an important role in the recent increase in opioid-related deaths.

The investigators conducted a population-based cohort study, examining data on 2,833 residents of Ontario who died of opioid-related causes between January 2013 and December 2016. Active opioid prescribing was defined as having at least one day’s supply of a drug overlapping the date of death, and recent opioid prescriptions as those dispensed 30 days, 180 days, one year, two years, and three years before the date of death. The study also reviewed benzodiazepine and specific aspects of fentanyl prescribing. Post mortem toxicology results were obtained for all deaths.

The mean age at death was 43 years, and 67% of those who died were male. Nearly 9% had been admitted for non-fatal opioid overdose in the year before death, 26% had a diagnosis of alcohol misuse disorder and 42% had visited an emergency department for the management of a mental health problem in the preceding three years.

In 2013, 38% of those dying of opioid-related causes had an active opioid prescription on their date of death. Although the absolute number of deaths involving an active prescription increased by 15% between 2013 and 2016 (from 241 to 278 deaths), the proportion of all deaths with an active opioid prescription fell to 32.5% in 2016. However, in 2016, 80% of those attending an emergency department for an ‘opioid toxicity event’ had received a prescription opioid in the past three years. Among people with active opioid prescribing at the time of death, 38% also had evidence of non-prescribed opioid use on post mortem toxicology.

Although its prevalence declined during the study period, active benzodiazepine prescriptions remained common, and in 2016 28% of people who died of an opioid-related cause had an active benzodiazepine prescription at the time of their death, while 16% had active prescriptions for both benzodiazepines and opioids.

Overall, people over 45 years and women were more likely to have active opioid prescribing at the time of death. Of those people with no active opioid prescribing, 47% of deaths involved fentanyl in 2016, a sharp increase from 20% in 2013.

The rise in opioid-related morbidity and mortality in North America over recent years has been described as an overdose crisis.1 It has been argued that one contributing factor to this rise has been the rapid increase in opioid prescribing for chronic non-cancer pain. Although opioid prescribing rates may have fallen in Canada in recent years, as many as one in eight residents of Ontario were prescribed opioid analgesia during 2016.²

The researchers comment: ‘The absolute number of people with an active opioid prescription who died of an overdose increased by 15% over our study period. This reinforces the need for responses to the opioid crisis that address all avenues through which people can access these drugs, including prescriptions, diverted drugs, and illicitly manufactured products.’

Dr Jez Thompson