Starting opioid agonist treatment after hospitalization for toxicity halves risk of repeat event

TORONTO - A new study led by researchers at the University of Toronto's Leslie Dan Faculty of Pharmacy and Unity Health Toronto shows that almost one quarter of hospital-treated opioid toxicities experienced a repeat event within six months, but early initiation of opioid agonist therapy (OAT) can cut that risk almost in half.

The research, published this week in BMJ Public Health, demonstrates the importance of connecting people who experience an opioid toxicity with community resources and treatment while they are in hospital.

“When people who use drugs are in hospital, it may be one of their few touchpoints with the health care system, and it’s an important opportunity to talk about their options,” says Shaleesa Ledlie, senior research associate at Unity Health and lead author of the study. “Not everyone who experiences a toxicity may want to engage with treatment, but for those who do, it's a great opportunity to initiate OAT and connect them with resources.”

The research was part of Ledlie’s PhD research at the Leslie Dan Faculty of Pharmacy, conducted under the supervision of Tara Gomes, associate professor (status) at the Leslie Dan Faculty of Pharmacy, epidemiologist at Unity Health, and principal investigator at the Ontario Drug Policy Research Network.

Canada is experiencing a significant unregulated drug toxicity crisis: In 2024, more than 5,500 hospitalizations and 7,100 deaths across Canada were attributed to opioid toxicities. Previous research has shown people who experience a toxicity are at high risk of a repeat event and other poor health care outcomes within a year of the initial event.

To examine OAT initiation after a hospitalization for opioid toxicity, Ledlie used population data of Ontario residents who were hospitalized for an opioid toxicity and data on OAT dispensing in Ontario community pharmacies from the Narcotics Monitoring System from 2014 to 2021. Using this anonymized data, she could examine how many people start OAT within 30 days of a toxicity event and how many of those who initiate OAT experience a repeat toxicity.

Using this large data set, Ledlie and the research team identified approximately 20,000 opioid toxicities that fit their study criteria, with some people experiencing multiple toxicities within the study period. Nearly a quarter of these experienced a repeat toxicity event within six months.

Only about 12 per cent of people who experienced a toxicity started OAT within 30 days of hospital discharge. But it was highly effective: OAT reduced the occurrence of repeat toxicity by about half, and the risk went down the longer the individual stayed on treatment.

“People who experience an opioid toxicity are at high risk of poor health outcomes and repeat events. Though many people at risk of opioid-related harms receive hospital care, too often those encounters are missed opportunities to connect them to treatment,” says Gomes. “Our findings show that when hospitals link patients to opioid agonist therapy during or soon after their stay, outcomes improve, underscoring the importance of integrated care within Ontario’s health system.”

Results highlight need for physician education and strong community connections

Importantly, the research was conducted with input from the Lived Experience Advisory Group, made up of people with lived experience with opioid toxicity, who contributed an important perspective on the research study design and interpretation of results.

Jes Besharah is one of the study’s co-authors and a member of the Lived Experience Advisory Group. She co-founded the Brockville Overdose Outreach Team, a grassroots organization that connects with the local community and people who use substances to provide naloxone kits and education around reversing opioid toxicities.

Besharah says she hopes that the research results will help educate physicians on the importance of making connections with community resources and providing patient-centred care for people who experience a toxicity.

“Every death from an opioid toxicity is preventable, and hospitals can play a much bigger role in addressing the situation. There’s so much stigma around opioid use, and historically in a lot of hospitals, people who are admitted for a toxicity haven’t been treated very well,” says Besharah, who currently works in the Concurrent Disorders Stabilization Unit at Brockville General Hospital, which provides support for people with mental health and substance use disorders.

“In my experience, connection is what allows people to make changes in their life. It’s not just about treatment – a lot of clinics now have caseworkers and social workers available, as well as access to harm reduction supplies. And even knowing that physicians and hospital staff care enough to recommend these resources can be huge for that patient.”

Ledlie agrees that the study highlights the need to provide more addictions medicine training and resources in hospital to support physicians and patients with treatment initiation, and she hopes the results will help inform policies that strengthen the connections between hospital and community resources.

“If people aren’t offered OAT in hospital and they don’t have a primary care provider, it can be difficult to make that connection in the community and start treatment,” says Ledlie.

“Addictions medicine services within hospitals can help connect people to treatment or harm reduction services, and training for physicians, especially in the emergency department, can prepare them for these conversations. This work highlights the importance of having resources in hospital to improve quality of care for this population.”

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