The cost of potentially inappropriate medications for older adults in Canada: A comparative cross-sectional study.

Background: Potentially inappropriate medications (PIMs) are medications whereby the harms may outweigh the benefits for a given individual. Although overprescribed to older adults, their direct costs on the healthcare system are poorly described.

Methods: This was a cross-sectional study of the cost of PIMs for Canadians aged 65 and older, using adapted criteria from the American Geriatrics Society. We examined prescription claims information from the National Prescription Drug Utilization Information System in 2021 and compared these with 2013. The overall levels of inflation-adjusted total annual expenditure on PIMs, average cost per quarterly exposure, and average quarterly exposures to PIMs were calculated in CAD$.

Results: Exposure to most categories of PIMs decreased, aside from gabapentinoids, proton pump inhibitors, and antipsychotics, all of which increased. Canadians spent $1 billion on PIMs in 2021, a 33.6% reduction compared with 2013 ($1.5 billion). In 2021, the largest annual expenditures were on proton pump inhibitors ($211 million) and gabapentinoids ($126 million). The quarterly amount spent on PIMs per person exposed decreased from $95 to $57. In terms of mean cost per person, opioids and antipsychotics were highest ($138 and $118 per exposure). Some cost savings may have occurred secondary to an observed decline of 16.4% in the quarterly rate of exposure to PIMs (from 7301 per 10,000 in 2013 to 6106 per 10,000 in 2021).

Conclusions: While expenditures on PIMs have declined in Canada, the overall cost remains high. Prescribing of some seriously harmful classes of PIMs has increased and so directed, scalable interventions are needed.