TORONTO, May 16, 2018 -- Nearly a quarter (23.9 per cent) of initial opioid prescriptions in Ontario had a daily dose of more than 50 milligram morphine equivalents (MME), exceeding the suggested dose threshold for opioid prescriptions outlined in North American clinical guidelines, according to a new study from the Institute for Clinical Evaluative Sciences (ICES) and St. Michael's Hospital.
"The U.S. and Canadian clinical guidelines for prescribing opioids for chronic non-cancer pain suggest that doctors should avoid initiating opioids at daily doses above 50 MME. Our study found that nearly one-quarter of Ontarians taking an opioid for the first time received a daily dose exceeding this threshold, and for certain indications such as knee, hip and shoulder surgeries and Caesarean sections, the dose was even higher," says Dr. Tara Gomes, lead author of the study and a scientist at ICES.
The study, published today in the journal Pain, examined initial opioid prescriptions for more than 650,000 Ontarians from April 2015 to March 2016 and linked each to health administrative data from Ontario's publicly funded health care system.
"Due to concerns about the overprescription of opioids, there is an ongoing need to determine how to resource alternative non-pharmaceutical pain management strategies . In order to do this, we wanted to get a clear picture of the clinical indications associated with opioid initiation and the characteristics of those initial prescriptions," adds Gomes, who is also a scientist at the Li Ka Shing Knowledge Institute of St. Michael's Hospital.
Prescriptions for opioids have increased sharply in the last decade, making Canada the second highest per-capita user of opioids in the world. Furthermore, 1 in 8 Ontarians was dispensed an opioid in 2016, and Ontario has seen a four-fold increase in overdose deaths in the last 25 years, according to earlier research by Gomes.
The researchers grouped the reasons for starting opioids into six clusters: dental pain (23.2 per cent of prescriptions), postsurgical pain (17.4 per cent), musculoskeletal pain (12.0 per cent), trauma-related pain (11.2 per cent), cancer or palliative care (6.5 per cent), and other types of pain (17.7 per cent). Overall, 78,481 (12.0 per cent) of individuals could not be linked to any of the six indications).
The study showed that the dose and duration of initial opioid prescriptions varied considerably by indication. Dental pain accounted for nearly one in four new opioid prescriptions, but these were generally of short duration and low dose. In contrast, one in six new opioid prescriptions were for postsurgical pain, and these patients generally started on higher daily doses (over 40 per cent of them were prescribed more than 50 MME, and for hip and knee surgery at least 25 per cent were prescribed 90 MME or more).
"We know that patients' first opioid prescriptions are critically important. Across all clinical indications, a high percentage of people received daily doses of more than 50MME and prescription lengths exceeding seven days, a combination which has been associated with opioid-related adverse events and long-term opioid use. Given this, we need to think about alternative pain management options. This data can help us understand the types of services - like physiotherapy and cognitive behavioural therapy - that might be appropriate to help avoid our reliance on opioids for some indications," says Gomes.
Note: To clarify, the results in this paper represent a time just prior to the release of the U.S. (2016) and Canadian (2017) guidelines for opioids for chronic non-cancer pain. Therefore, these findings provide important information regarding opioid initiation practices just prior to the release of new dose recommendations. Given the degree to which opioid initiation at doses above 50MME occurred at this time, it is hoped that these new guidelines will promote more appropriate prescribing. Future research will attempt to understand how these patterns shift as the guidelines are disseminated.
"Clinical indications associated with opioid initiation for pain management in Ontario, Canada: A population-based cohort study," was published in the current issue of PAIN.
Author block: Sachin V. Pasricha, Mina Tadrous, Wayne Khuu, David N. Juurlink, Muhammad M. Mamdani, J. Michael Paterson and Tara Gomes.
The Institute for Clinical Evaluative Sciences (ICES) is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of health care issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting health care needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.
About St. Michael's Hospital
St. Michael's Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future health care professionals in more than 29 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the Hospital's recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael's Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.
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