The Canadian Medical Association Journal (CMAJ) on Monday released a large study led by McMaster University that found the risk of fatal and non-fatal opioid overdose after prescription increased up to sixfold in cases involving predictors such as a high dose of medication, depression, or pancreatitis.
“The conversation really needs to be around opioid stewardship and responsible opioid prescribing because we can’t and we shouldn’t get rid of opioids,” explained Jennifer Jackson, a registered nurse and an assistant professor at the University of Calgary.
“We need them to treat people who are suffering. However, we also have to look at what other options we have and whether it’s the best choice,” she added.
“Chronic back pain is not a good use of opioids, but we also can’t throw the baby out with the bathwater… if you have surgery or if you have cancer, you need opioids. And so they are a tool, but we have to use that tool correctly,” she said.
Around 7.6 million people in Canada live with chronic pain, according to a 2021 report by the Canadian Pain Task Force.
Pain management for chronic pain relies heavily on prescription opioid treatment, such as codeine, fentanyl, morphine and oxycodone, and has contributed to the development of the opioid crisis in Canada. This is because the longer-term side effects of using opioids may include increased tolerance, substance use disorder or dependence, and overdose, according to Health Canada.
In order to identify factors associated with fatal and nonfatal overdose from prescription opioids, the researchers looked at data between 2007 and 2022 from 24 million patients in Canada, the United States and the United Kingdom. These patients had been prescribed opioids for non-cancer and cancer-related chronic pain.
“This study reported 103 predictors, but we found 10 predictors particularly important because they showed a very large association where it increased the risk of opioid overdose by two to six times compared to those patients who didn’t have factors like these,” said Li Wang, co-author and assistant professor in anesthesia within McMaster’s Faculty of Health Sciences in Hamilton, Ont.
“We call them serious harms,” she added.
The 10 predictors that were strongly associated with opioid overdose, according to the study, include:
- High-dose opioids
- Use of multiple pharmacies
- Multiple opioid prescribers
- Fentanyl prescription
- Current substance use disorder
- Bipolar disorder
- Other mental illness
- History of opioid overdose
“These are very important risk factors,” Wang said. “We hope in the future we can figure out more harm reduction strategies to prevent or migrate these types of risk and prevent future fatal or non-fatal overdose. That’s the goal.”
Highest-risk factors of opioid overdose
Referring to the study as “credible,” Jackson said the findings “add to what we already know about chronic opioid use.”
One of the most significant risk factors for opioid addiction or overdose, as identified by the researchers and Jackson, is the practice of obtaining opioids from multiple pharmacies or multiple prescribers.
“We call them doctor shopping or pharmacy shopping,” Wang said. “The patients tend to go to multiple pharmacies or prescribers to get the opioids.”
The study found that patients who seek out multiple prescribers or pharmacies for opioids were almost five times more likely to overdose.
“These are pretty significant red flags that someone is developing unhealthy behaviour around opioid use. And rather than say, ‘We’re going to try and cut them off from different providers’, there needs to be a discussion if we’re starting to see some escalating behaviour. How can we offer support if that person wants it with their consent?” Jackson said.
The researchers and Jackson see this as a “warning sign” that requires engagement rather than “cut-offs.”
This is because if a person is addicted to opioids, “you cannot physiologically just stop taking” them, Jackson said. “Withdrawal is life-threatening, it can be fatal if your body’s biochemistry has changed, it is not a choice anymore.”
Another notable risk factor, as explained by Wang, was the use of “high-dose opioids.”
The Canadian guidelines for opioids in cases of chronic non-cancer pain highly recommend a prescribed dose of less than 90 milligrams.
If a patient receives a prescription exceeding 90 milligrams, the study revealed a 2.6 times greater risk of experiencing an overdose.
A prior study conducted by the Canadian Institute of Health Information (CIHI) in 2019 corroborated these findings, emphasizing the heightened risks linked to high opioid doses. The research found that patients prescribed a daily opioid dose exceeding 90 milligrams faced a heightened risk of drug-related fatalities compared to those on lower-prescribed doses.
The study’s most prominent risk factor for overdose was an association with a history of prior overdoses, making individuals nearly six times more likely to experience another one.
Wang said she hopes these 10 predictors will help create collaborative decision-making between doctors and their patients when it comes to prescribing opioids for chronic pain. The goal is to assess the potential harm in relation to the possible benefits of the treatment.
“Our research findings can try to help doctors and patients with chronic pain management,” she said. “To support the decision-making process about whether the (patient) should use opioids for chronic management or other factors should be paid attention to.”