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OTTAWA, April 12, 2004 -- One in eight hospitalized patients experience some form of adverse event or complication resulting from medical treatments, suggests a new study by a group of doctors at The Ottawa Hospital. In some cases, these adverse events may be preventable. This is the first Canadian effort to document the frequency and type of adverse events happening in hospital. It appears in the April 13th edition of the Canadian Medical Association Journal.

"This study reminds us that there are inherent risks in medical care," said Dr. Jack Kitts, President and CEO of The Ottawa Hospital, "but some of those risks are preventable."

"For The Ottawa Hospital, supporting this type of research, and sharing our experience with others across Canada, is critical as the healthcare system begins to understand the scope of this patient safety issue," added Dr. Kitts.

According to the study, an adverse event is defined as a poor outcome resulting from a treatment or other medical intervention. These can vary in severity from mild discomfort all the way to disability or death. Some adverse events are common and predictable, such as nausea and vomiting following chemotherapy. In other cases, adverse events occur as a result of preventable errors, such as giving a patient the wrong medication or misdiagnosing a medical problem.

This new study reviewed the health records of 502 patients admitted to The Ottawa Hospital over a one-year period. Of those, 64 patients had an adverse event documented in their health record, or 1 in every 8 patients. "Our study shows that adverse events are relatively common, and that most are due to medical care that is appropriate and correctly given," said the study's lead author, Dr. Alan Forster. Dr. Forster is an Internal Medicine Specialist at The Ottawa Hospital, an Associate Scientist at the Ottawa Hospital Research Institute and an Associate Professor of Medicine at the University of Ottawa.

The study also documented that some patients experienced adverse events that should not have occurred. "In almost 5 % of the cases we studied, we noted that the adverse event could have been prevented," said Dr. Forster. The leading causes of preventable adverse events were medication errors or hospital-acquired infections. "There is strong evidence that preventable events are not the result of 'bad hospitals' or 'bad care providers'," said Forster. "Rather, the research suggests that these are more likely due to the way the healthcare system is organized, particularly because of gaps in coordination between the different providers of patient care."

While some adverse events happened in hospital, almost two thirds of those observed in the study occurred before hospital admission while patients were being cared for in the community. "This suggests that hospitals are not solely responsible for improving patient safety on their own," said Dr. Forster. "We have to work together with community providers, such as family doctors, walk-in clinics, nursing homes, and others to really be successful in reducing preventable errors."

"As a result of an early look at Dr. Forster's and his team's findings, we have already taken steps to reduce adverse events at The Ottawa Hospital, particularly preventable ones," said Wendy Nicklin, Vice-President responsible for patient safety and a founding Board member of the Canadian Patient Safety Institute. "We have put in place new protocols to improve the dispensing of medications that carry significant risks," she said, "we have also significantly improved infection control practices across the hospital."

"Supporting Dr. Forster and his research team is part of The Ottawa Hospital's comprehensive strategy to expand our knowledge about how to improve patient safety and, by sharing what we learn, to make this issue a top priority for all healthcare providers locally and nationally," Ms. Nicklin added.

This study by Dr. Forster and his research team was made possible by a research grant from The Ottawa Hospital and the Ottawa Internists Research Group.


Media Contact: Sharon Way, Public Affairs and Media Relations, 613-737-8899 ext. 74507,



  • This is the second publication on adverse events for Dr. Forster and his team in 2004. In the February 2nd edition of CMAJ, they reported on the incidence of adverse events that occur once patients are discharged from hospital. The findings suggested that better integration of the healthcare system could help reduce the rate of adverse events post-hospital discharge.

  • This new study reviewed the medical records of patients after they were hospitalized to determine if and when an adverse event occurred. The study is a precursor to a cross-Canada study led by Professors Norton and Baker targeted for publication later this spring.

  • The results of this study are very similar to research performed in other countries. That is, the frequency, preventability and type of adverse events are similar at this hospital compared to research performed internationally.

  • One important difference, however, is that more patients in this study experienced their adverse event before they were admitted to hospital. The reasons for this difference is unknown but the researchers speculate that it may be due to the inclusiveness of Canada's healthcare system (more patients receive treatments, therefore more patients have complications), the adequacy of our primary care system (less efficient monitoring of patients in the community), or study methodology (the study hospital is a teaching hospital and may therefore patients who are admitted may have more serious and complex health conditions than patients admitted elsewhere).

  • The study also found that the risk of an adverse event was significantly associated with age (i.e. the older the patient, the greater the risk).

  • The Ottawa Hospital has already learned from an early look at the study's findings. Protocols for medications known to have high risks have been reviewed and standardized across the hospital. Multiple checks are required for some medications before they can be administered. Infection control practices have been improved across the hospital. A new electronic clinical information system ensures that up-to-date, real-time patient information is readily available in all patient care areas across the hospital.

  • Supporting and sharing this type of research is part of The Ottawa Hospital's leadership role in patient safety. By studying how and why adverse events occur, including those that are preventable, and by sharing this experience with health care providers across Canada, The Ottawa Hospital is helping to more closely target efforts to improve patient safety throughout the health care system.

About The Ottawa Hospital

The Ottawa Hospital is a multi-campus academic health sciences centre. With over 1000 beds, 10,000 staff plus 1200 physicians, and an annual operating budget of over $600 million, it is one of the largest healthcare organizations in Canada.

In collaboration with the Ottawa Hospital Research Institute and the University of Ottawa, the Hospital is dedicated to excellence in patient care, to the education of future healthcare professionals, and to research resulting in innovative ways to prevent, diagnose and treat injuries and illness.

The Ottawa Hospital partners with various organizations to provide comprehensive, high quality, patient-focused healthcare services, in English and French, to over 1.5 million residents of eastern and northeastern Ontario.

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