A comprehensive study conducted across Ontario, Canada, has identified a widespread issue where commonly prescribed medications, such as statins and iron supplements, can trigger a chain of subsequent prescriptions in older adults. Researchers found that side effects from an initial drug are often misinterpreted as new health conditions, leading to further, potentially unnecessary, treatments.
The findings, published in the medical journal BMJ, suggest that these sequences of prescriptions represent a significant, yet frequently overlooked, source of drug-related harm across the general population. Beyond the potential for patient harm, these prescribing patterns also contribute to avoidable costs within healthcare systems.
The research was spearheaded by Dr Paula Rochon, who serves as the Director of Research at the Weston and O'Born Center for Mature Women's Health at Sinai Health in Toronto. Dr Rochon, also a professor of medicine at the University of Toronto and holder of the Barry J. Goldlist Chair in Aging and Health at Sinai Health, emphasised the importance of addressing this issue.
When a Side Effect Leads to Another Prescription
This phenomenon is formally termed a ‘potentially inappropriate prescribing cascade’ (PIPC). It describes a scenario where a side effect induced by one medication is misdiagnosed as a distinct health problem, prompting the prescription of another drug that may not have been necessary.
One illustrative example highlighted by the researchers involves non-steroidal anti-inflammatory drugs (NSAIDs), which are frequently prescribed for pain management. NSAIDs are known to increase blood pressure. If this rise in blood pressure is then treated as a new case of hypertension, the patient may be given an additional medication to lower blood pressure, rather than re-evaluating the original pain treatment.
Older adults are particularly vulnerable to these cascades. This is largely due to their increased likelihood of suffering from multiple health conditions, which often necessitates taking several medications concurrently. When numerous drugs are involved, it becomes considerably more challenging for both healthcare professionals and patients to discern whether a new symptom is a genuine new condition or merely a side effect of an existing prescription.
"These sequences of events are common but often missed in clinical practice," stated Dr Rochon. She underscored the critical need for vigilance: "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."
Researchers Identify 24 Common Prescribing Cascades
The extensive project brought together an interdisciplinary international team of experts in medication prescribing and geriatric medicine, with collaborators joining from the United States, Belgium, Italy, Israel, and Ireland. The Sinai Health team included Drs Vasily Giannakeas, Nathan Stall, and Christina Reppas-Rindlisbacher, alongside research staff Wei Wu and Joyce Li.
In preceding work, the research group had leveraged the collective expertise of 12 international panellists, all specialists in internal medicine, geriatric medicine, and clinical pharmacology. This initial phase led to the development of a comprehensive list encompassing 65 distinct PIPCs.
For the subsequent in-depth analysis, this established list of PIPCs was cross-referenced with population-level prescription data obtained from ICES, Ontario’s health data institute. The ICES team, including Lavina Matai and Zhiyin Li, assisted in this crucial stage. Each potential cascade was rigorously evaluated using three specific metrics: the frequency with which the initial medication was prescribed, the regularity with which a second medication followed it, and the statistical strength of the connection between the two prescriptions.
This meticulous process enabled the researchers to pinpoint 24 potentially inappropriate prescribing cascades that were not only commonly observed across the population but also carried a significant potential for causing harm to patients.
For Dr Rochon, these findings highlight a critical communication gap that frequently emerges as patients accumulate various medications over time. "Our concern is that so often these conversations between the healthcare prescriber and the patient are being missed, so people don't recognise the sequences of events and that they are connected to one another," she explained.
Addressing this complex problem requires a more holistic approach than simply reviewing a current list of a patient's medications. Physicians need to delve deeper, considering the specific date each drug was introduced, the precise reason for its prescription, and crucially, whether a more recently added medication was prescribed to alleviate a symptom that could, in fact, have been caused by an earlier treatment.
The implications of these findings may be particularly pertinent for mature women. Throughout their lives, women statistically tend to experience a greater number of chronic conditions than men, consequently receiving more drug therapies and experiencing a higher incidence of adverse drug events.
Taking multiple medications inherently increases the likelihood that a side effect might be misinterpreted as a separate, distinct diagnosis. This misinterpretation can lead to the addition of another drug to the treatment regimen, rather than correctly tracing the symptom back to the original medication responsible for its onset.
Addressing the Problem with Technology and Pharmacist Involvement
The researchers propose that technology could offer a viable pathway to mitigate these potentially harmful prescribing patterns. Automated clinical decision support systems, for instance, could be specifically designed to recognise a possible prescribing cascade as it begins to develop.
Such intelligent systems could be programmed to alert clinicians when a new medication appears to be prescribed for a symptom that is a known side effect of an existing drug. This would provide healthcare providers with a crucial opportunity to pause and reconsider the patient's treatment plan, potentially preventing the addition of an unnecessary prescription.
This vital information could be seamlessly integrated into various forms of automated tools, thereby empowering clinicians with timely alerts regarding potentially inappropriate prescribing cascades directly at the point of care.
Beyond technological solutions, the researchers also identify a significant opportunity to better utilise the expertise of pharmacists as integral members of the healthcare team. By more directly involving pharmacists in prescribing decisions, working in close collaboration with physicians, it could help to uncover medication patterns that might otherwise go unnoticed.
The specialist knowledge of pharmacists could prove invaluable in identifying potentially inappropriate prescribing cascades that warrant further, careful evaluation, ultimately enhancing patient safety and optimising treatment outcomes.
Materials for this report were provided by the Lunenfeld-Tanenbaum Research Institute.
