Deaths from opioid use in Ontario, Canada, have doubled since 1991 and the addition of long-acting oxycodone to the drug formulary was associated with a 5-fold increase in oxycodone-related deaths, found a new study in CMAJ (Canadian Medical Association Journal). Most of these additional deaths were accidental.
Opioids are among the most commonly prescribed medications in Canada and are often used for patients with chronic non-malignant pain. Other studies have argued that prescribing is not a major contributor to the adverse health effects of opioid abuse, yet this study suggests that increased rates of opioid prescriptions are a significant factor in accidental opioid-related deaths.
The study looked at prescribing data from 1991 to 2007 from IMS Health Canada, which collects information from almost two-thirds of Canadian pharmacies, and deaths attributed to opioid use from records of the Office of the Chief Coroner of Ontario between 1991 and 2004. It also linked the coroner's data to health care databases to track patients' medical visits.
Prescriptions for opioid pain medications increased by 29%, with codeine the most frequently prescribed, although the number of prescriptions for that drug declined during the study period. Oxycodone prescriptions rose more than 850%, much more rapidly than any other opioid, and accounted for 32% of the almost 7.2 million prescriptions for opioids dispensed in 2006.
Between 1991 and 2004, 7099 deaths with complete records were attributed to alcohol and/or drugs. In 3406 of these deaths -- 61.9% -- opioids were implicated as cause of death. The median age of death was 40 years and 67% were men. Suicide was a factor in 23.6% of deaths.
"The rise in opioid-related deaths was due in large part to inadvertent toxicity," write Dr. Irfan Dhalla, of the University of Toronto and coauthors. "There was no significant increase in the number of deaths from suicide involving opioids over the study period."
After linking the coroner's data to health care databases, the researchers included 3066 deaths. Many (66.4%) of these patients had seen a physician at least once in the 4 weeks preceding their death, with diagnosis of mental health problems and pain-related complaints the most common reasons for medical attention.
"The societal burden of opioid-related mortality and morbidity in Canada is substantial," write the authors. "In our study, the annual incidence of opioid-related deaths in 2004 (27.2 million) falls between the incidence of death from HIV infection (12 per million) and sepsis (40 per million)."
They conclude that the frequency of visits to physicians and opioid prescriptions in the month before death suggest a missed opportunity for prevention.
In a related commentary, Dr. Benedikt Fischer of Simon Fraser University and coauthor write "the pre-eminent risk in most deaths was from the use of multiple drugs involving prescription opioids and other substances that are widely and legally dispensed. As prescription drugs are involved in more overdose deaths than either heroin or cocaine in North America, the profile of the people who are dying may be changing from marginalized people to more "middle class."
The authors argue that governments must lead in developing a preventative strategy for this different demographic and refocus the federal drug policy that currently targets marginalized people.
- Irfan A. Dhalla, Muhammad M. Mamdani, Marco L.A. Sivilotti, Alex Kopp, Omar Qureshi, David N. Juurlink. Prescribing of opioid analgesics and related mortality before and after the introduction of long-acting oxycodone. Canadian Medical Association Journal, 2009; 181 (12): 891 DOI: 10.1503/cmaj.090784
- Benedikt Fischer, Jürgen Rehm. Deaths related to the use of prescription opioids. Canadian Medical Association Journal, 2009; DOI: 10.1503/cmaj.091791
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