More Than 153,000 Patients Experienced Harm in Canadian Hospitals Last Year: Study

A patient walks down a hallway in the emergency ward at a hospital in Montreal on Sept. 19, 2024. The Canadian Press/Christinne Muschi

More than 153,000 people experienced harm that was potentially preventable while hospitalized in Canada in 2024–25, according to a recent study.

Of those who were harmed while hospitalized, one out of four experienced multiple harmful events, according to data published by the Canadian Institute for Health Information (CIHI) on Sept. 25.

“Hospitals are generally safe, but sometimes harmful events happen that affect patients,” CIHI said. “Many of these events are preventable.”

The types of unintended harm experienced by Canadians in hospitals include medication-related errors, infections incurred during hospital stay, patient accidents such as falls or burns, as well as conditions that result from medical procedures or devices, the organization said.

The study is based on 2.6 million hospital stays during the last fiscal year across the country, excluding data from Quebec and for some mental health patients. CIHI says the incidents could have potentially been prevented by implementing “evidence-informed practices.”

Based on the number of events that occurred in acute care hospitals last year, the top six harmful events were electrolyte and fluid imbalance, urinary tract infections, delirium, pneumonia, aspiration pneumonitis, and post-procedural infections.

Those who experienced harm stayed in hospital nearly five times longer, at 28 days on average, while those who did not experience harm stayed in hospital for an average of six days, CIHI said.

Additionally, the study found the average cost of hospitalization for patients who experienced an unintended harm event was more than four times the cost of hospitalization for patients without harm. The average cost to hospitalize a patient with harm was $44,641 compared to $9,792 for those without.

Unintended harm events were most common among those over the age of 65, with 68,915 events occurring for those aged 65 to 84, and 28,191 events occurring for those aged 84 and older. Instances of harm acquired in hospital were less common for younger people, with 6,175 individuals under the age of 17 experiencing harm.

The rate of harmful events has remained steady at around six events per 100 hospitalizations since the COVID-19 pandemic began in 2020. From 2014 to 2019, the rate was approximately 5.3 events per 100 hospitalizations.

The study follows a 2016 CIHI report which estimated that patients suffered harm in more than 138,000 different hospitalizations in 2014–15, while one in five of those involved more than one occurrence of harm. This represented approximately one in every 18 hospitalizations experiencing harm, which increased to one in every 17 hospitalizations in the 2025 study.

“It’s estimated that on any given day more than 1,600 hospital beds across the country are occupied by a patient who suffered harm that extended his or her hospital stay,” the 2016 report said. “In addition to what these patients and their families go through, their continued need for treatment also has a cost to the system, in that it keeps other people from getting the help they need.”

A 2025 report in the Healthcare Quarterly journal said the focus on patient safety in hospitals has changed as other priorities such as recovery efforts and workforce burnout have taken the spotlight following the pandemic.

“The focus on patient safety in Canada has been displaced — not because the safety issues have been solved, but because priorities have shifted,” the report says.