New research provides much-needed data on in-hospital antibiotic use

Understanding variation in physician prescribing patterns and patient outcomes is key to addressing unnecessary antimicrobial use

New pharmacist-led research, published by the Canadian Medical Association Journal in August, is providing important information about antimicrobial prescribing in hospitals and helping health care professionals develop targeted approaches to reducing unnecessary antimicrobial use in hospital settings.

“We all agree that we want to optimize antimicrobial prescribing, and we haven’t had the information available to know how best to do it,” says Mark McIntyre, lead author of the study and assistant professor (status) at the Leslie Dan Faculty of Pharmacy. “This study is just one piece of the puzzle, providing information on in-hospital prescribing, that can help us figure out how to do use antimicrobials better.”

Antimicrobial resistance is a significant and accelerating challenge facing health care today and in the coming years. Some research estimates that by 2050 more people will die of antimicrobial resistance than of cancer. Antimicrobial stewardship is an approach that supports health care providers to use the right amount of antimicrobials for a given patient – no more, no less.

But determining the “right amount” has been challenging. There hasn’t been much information available on physicians’ prescribing practices and how prescribing is related to patients’ characteristics or outcomes.

“Every health care provider wants to do what is best for their patients,” says McIntyre, who is also the program lead in antimicrobial stewardship at Sinai Health. “But the fact is that we don’t know where the ‘Goldilocks zone’ is when it comes to figuring out high prescribing or low prescribing. What is the right amount of prescribing?”

McIntyre and a team of physicians and academics wanted to gain a better understanding of how antimicrobial prescribing patterns vary among physicians, whether this variance is due to differences in their patients, and if it changes patient outcomes.

The team had access to a large data set -- 10 years of prescribing data from four Toronto hospitals, which included 124 physicians and 124,000 patient admissions – which allowed them to see the big picture of how many antimicrobials physicians prescribed in hospital settings and look for trends in patients based on whether physicians were considered high or low prescribers.

Analysis showed that the highest prescribing physicians prescribed 30 per cent more antimicrobials than the lowest prescribing physicians. But importantly, they found that there were no significant differences in patient characteristics or outcomes regardless of whether physicians were high or low prescribers – a finding that supports the position that, when it comes to antimicrobials, more is not always better.

Results will be used to develop targeted antimicrobial stewardship strategies for physicians

“This study shows that higher prescribing, through either more antibiotics or broader spectrum antibiotics, does not seem to improve patient care. And we know that higher prescribing is associated with a higher risk of side effects and emergence of antimicrobial resistance,” says senior author Dr. Fahad Razak, a general internist at St. Michael’s Hospital and associate professor at U of T’s Temerty Faculty of Medicine and Institute of Health Policy, Management and Evaluation.

Dr. Razak, who leads a research program that analyzes large data sets to improve patient care, says that the study provides valuable information on in-hospital prescribing that can be used to change clinical practice.

“There is very little systematic information on how physicians prescribe antibiotics on hospital medical wards. This study is the best description to date and lays the groundwork for a future randomized trial that will determine if we can safely reduce prescribing by providing physicians with this information and comparing that against peers,” he says. “If successful, we have the potential to change clinical practice, using less unnecessary antibiotics while still providing high quality care.”

McIntyre says that one way to change practice is to develop more targeted antimicrobial stewardship initiatives with messages that resonate with physicians who prescribe antimicrobials at different levels. Physicians who are in the lowest-prescribing group can also champion initiatives to reduce antimicrobial use among physicians who prescribe them more.

“Before this study, we didn’t even know how much physicians varied in their prescribing practices, and now we know,” says McIntyre. “Seeing that we don’t have worse outcomes in patients for physicians who prescribe lower puts us in a good position to do the next bit of work to help bring more physicians down in their antimicrobial prescribing.”

McIntyre emphasizes that this research, and antimicrobial stewardship more generally, is focused on addressing this complex, multifaceted problem and can only be done by working collaboratively with the entire health care team. And pharmacists, as drug experts and trusted members of the team, have an important role in advising prescribers on antimicrobial use.

“Interprofessional collaboration is crucial to help us to get the work done,” he says. “Pharmacists are valuable and trusted members of the interprofessional care team, and enhancing antimicrobial stewardship can be another focus of the work that we already do.”