Abstract
Objective
To explore the prescribing of potentially inappropriate drug therapy in Ontario, Canada where there is a restrictive drug formulary relative to the US where there is no single drug formulary.
Methods
A retrospective, cohort study using an administrative database (Ontario, Canada) compared with published survey results (US). All 1 088 680 community-dwelling adults ≥66 years of age in Ontario, Canada compared with published survey results from 2455 community-dwelling older adults in the US in 1996.
Patterns of potentially inappropriate drug prescribing were compared between countries using a list of 33 potentially inappropriate drug therapies. These therapies were classified by an expert panel into three categories: (i) those to always avoid; (ii) those which are rarely appropriate; and (iii) those with only some indications to prescribe.
Results
Among the 33 potentially inappropriate drug therapies, 15 (45%) prescribed in the US were not available through Ontario’s drug formulary. Potentially inappropriate drug therapies available through the Ontario Drug Benefit Plan (ODB) and also in the US were frequently prescribed in both Ontario and the US. Differences in prescribing patterns of individual drug therapies were noted between the two countries. Specifically, in the rarely appropriate category, diazepam, a long half-life benzodiazepine, was much more frequently dispensed in Ontario than in the US (3.18% vs 1.37%). In contrast, dextropropoxyphene, an opioid with a poor adverse event profile was more frequently prescribed in the US than in Ontario (6.21% vs 0.74%).
Conclusion
Almost half of the potentially inappropriate drug therapies that are available in the US are unavailable from Ontario’s drug formulary. Potentially inappropriate drug therapies that were available through the ODB were frequently prescribed in both countries. Alternative approaches that make information immediately accessible to physicians at the time they make prescribing decisions should be considered to improve prescribing practices.
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Acknowledgements
Funding: This work was supported by the Canadian Institutes of Health Research Chronic Disease New Emerging Team program (NET — 54010). The NET program receives joint sponsorship from the Canadian Diabetes Association, the Kidney Foundation of Canada, the Heart and Stroke Foundation of Canada and the Canadian Institutes of Health Research Institutes of Nutrition, Metabolism and Diabetes and Circulatory and Respiratory Health. Dr Paula Rochon was supported by an Investigator Award from the Canadian Institutes of Health Research and received funding from a Premier’s Research Excellence Award from the government of Ontario. Dr Susan Bronskill and Dr Muhammad Mamdani were supported by New Investigator Awards from NET.
Thank you to NET team members (Sudeep Gill, MD, Michael Hillmer, Kenneth Shulman, MD, Walter Woodchis, PhD and Susan Garfinkel, MSc) for their comments on earlier drafts of the manuscript and to Penelope deNobrega, RN, Monica Lee, MSc and Azad Mashari for their assistance in manuscript preparation.
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Rochon, P.A., Lane, C.J., Bronskill, S.E. et al. Potentially Inappropriate Prescribing in Canada Relative to the US. Drugs Aging 21, 939–947 (2004). https://doi.org/10.2165/00002512-200421140-00004
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DOI: https://doi.org/10.2165/00002512-200421140-00004