Background In the past decade, many countries have seen a significant increase in their drug-related mortality rates. In the United States (US), drug-related deaths now outnumber deaths from any other injury cause. To better understand international differences, this study compared drug-related deaths in the US, England/Wales, Scotland and Australia, examining trends, demographic characteristics and differences in the drugs involved.

Methods Drug-related deaths were identified using public access data and reports from each country’s statistical office. Cases were selected based on ICD–10 underlying cause codes of F11–16, F18–F19 (Drug abuse), X40–X44 (Accidental poisoning), X60–X64 (Intentional self-poisoning), X85 (Assault by drugs) and Y10–14 (Drug poisoning of undetermined intent).

Results In 2013, the rate of drug-related deaths in the US (146 per million population) was 1.5 times the rate in Scotland, twice the rate in Australia and more than 3 times the rate in England/Wales. In all countries, rates were higher for males than for females, with the greatest gender difference seen in Scotland. For underlying cause, in all countries, the majority of the deaths were accidental, however in England/Wales a higher percent were intentional (33%), in Australia a higher percent had a mental/behavioural cause (15%) and in Scotland a higher percent were categorised as undetermined intent (17%). In all countries, opioids including morphine, heroin and methadone were implicated in a high percent of the deaths, although drug-specific comparisons were limited due to variation by country in the completeness of the information on specific drugs.

Conclusions While similar patterns in drug-related deaths were identified, differences were also seen. The extent to which these differences are true or due to variation in death investigation, reporting and coding is unclear. Further work is needed to enhance the international comparability of mortality data on drug-related deaths.