A new Ontario-wide study reveals that common medications, from statins to iron supplements, can set off an unintentional cascade of prescriptions that leave many older adults taking drugs to treat side effects of other drugs.
The research, published in BMJ , revealed that certain drug combinations are a common but unrecognized contributor to drug-related harm at the population level and add unnecessary costs to the health-care system.
A potentially inappropriate prescribing cascade, as the phenomenon is known, happens when a medication's side effect is mistaken for a new health problem, leading to another prescription that may not have been needed in the first place.
One common example flagged in the study involves non-steroidal anti-inflammatory drugs. Commonly prescribed for pain, these drugs are associated with a rise in blood pressure, which can lead to a new prescription for high blood pressure instead of a second look at the original pain medication. Older adults are especially vulnerable to this pattern because they're more likely to experience multiple conditions requiring multiple medications.
"These sequences of events are common but often missed in clinical practice," says Paula Rochon, a senior clinician scientist at Sinai Health and professor in the department of medicine in the University of Toronto's Temerty Faculty of Medicine who serves as the director of research at the Weston and O'Born Centre for Mature Women's Health at Sinai Health.
"Knowing what medications you are taking, when they were started and for what indication is important in order to identify possible prescribing cascades that may be problematic."
The study brought together an interdisciplinary, international team of collaborators and leaders in drug prescribing and geriatric medicine research from the United States, Belgium, Italy, Israel and Ireland, along with Sinai Health researchers and U of T faculty members Vasily Giannakeas (Dalla Lana School of Public Health) and Nathan Stall (Temerty Medicine), geriatrician Christina Reppas-Rindlisbacher and research staff Wei Wu and Joyce Li.
The research team previously created a list of 65 potentially inappropriate prescribing cascades, drawing on the expertise of a dozen international panellists specializing in internal medicine, geriatric medicine and clinical pharmacology.
Using this list and population-level prescription data from ICES , Ontario's health data institute, the researchers examined each potentially inappropriate prescribing cascade against three factors: how common the initial drug was in the population, how often it was followed by the second drug and how strong the link was between the two. That analysis allowed the team to pinpoint the 24 potentially inappropriate prescribing cascades most commonly seen in the population with a potential to cause harm.
Seeing the pattern behind every prescription
For Rochon, the findings highlight a problem that begins quietly - one prescription at a time. "Our concern is that so often these conversations between the health-care prescriber and the patient are being missed, so people don't recognize the sequences of events and that they are connected to one another," she says.
Addressing the issue requires physicians to think about medication history at every visit - not just what drugs a patient is currently taking, but why each drug was prescribed in the first place and whether subsequent ones were actually needed.
The work carries a particular weight for mature women, as they tend to live with more chronic conditions than men, leading to more drug therapies and more adverse drug events.
The team's findings could help inform next steps.
The first involves technology. Automated clinical decision support tools could flag a prescribing cascade in real time, making clinicians aware of potentially inappropriate prescribing cascades at the point of care.
The second strategy involves more directly integrating pharmacists in a patient's care team. By including them alongside physicians during the prescribing process, pharmacists can use their expertise to help flag potentially inappropriate prescribing cascades for further evaluation.
This research was funded by the Canadian Institutes of Health Research and supported by ICES.
