Special article
Synergy between publication and promotion: comparing adoption of new evidence in Canada and the United States

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Abstract

Purpose

Few studies have examined the effect of new evidence from clinical trials on physician practice. We took advantage of differences in promotional activity in Canada and the United States for the Heart Outcomes Prevention and Evaluation (HOPE) study and the Randomized Aldactone Evaluation Study (RALES) to determine if publication of new evidence changes practice, and the extent to which promotion influences adoption of new evidence.

Methods

We used longitudinal dispensing data, collected from 1998 to 2001, to examine changes in prescribing patterns for ramipril and other angiotensin-converting enzyme (ACE) inhibitors before and after the HOPE study. We also obtained estimates for promotional expenditures. We stratified analyses by country, to isolate the effect of promotion, and used interrupted time series methods to adjust for pre-existing prescribing trends. Similar analyses were conducted for spironolactone use before and after RALES.

Results

Publication of the HOPE study results was associated with rapid increases in the use of ramipril. After adjusting for pre-existing prescribing trends, ramipril prescribing increased by 12% per month (P = 0.001) in Canada versus 5% per month (P = 0.001) in the United States after the study results were presented and published. One year later, ramipril accounted for 30% of the ACE inhibitor market in Canada versus 6% in the United States. The year before publication of these results, expenditures for detailing increased by 20% in Canada (to $18 per physician) but decreased by 7% in the United States (to $13 per physician); the year after publication, spending increased to $27 per physician in Canada versus $23 per physician in the United States. In the absence of promotional activity for RALES in either country, publication of results was associated with more modest but similar increases of 2% per month (P = 0.001) in spironolactone use in both countries.

Conclusion

Publication of new evidence is associated with modest changes in practice. Promotional activity appears to increase the adoption of evidence. Rather than relying on the publication of articles and creation of guidelines, those wishing to accelerate the adoption of new evidence may need to undertake more active promotion.

Section snippets

Study selection

In brief, the HOPE study was a Canadian-led multinational trial involving 9297 patients at high risk of cardiovascular events; 26% of the study sites were in Canada (13). High risk was defined as age >55 years with vascular disease (e.g., coronary disease, stroke) or diabetes plus one additional risk factor (e.g., hypertension, dyslipidemia, microalbuminuria). The primary outcome was the composite of myocardial infarction, stroke, or cardiovascular death. The study was stopped early because of

Results

From 1998 through 2001, the total number of ACE inhibitors dispensed increased by 42% in Canada (from 8.1 to 11.5 million prescriptions per year) and by 22% in the United States (from 82.5 to 100.3 million prescriptions per year). Before publication of the HOPE study, prescribing of ramipril increased slowly in Canada, at a rate of 3% per month (Figure 1; P = 0.001); in the United States, the rate of increase was even slower, at 1% per month (P = 0.02).

The prerelease and publication of the HOPE

Discussion

We found that the prerelease and publication of the HOPE study was associated with a substantial increase in prescriptions for ramipril in Canada and the United States. These increases occurred as soon as the evidence became available. The rate of increase in the use of ramipril in Canada was twice that in the United States, and 1 year after the publication of the study ramipril accounted for 30% of all ACE inhibitors prescribed in Canada and 6% in the United States. In comparison, the rate of

Acknowledgements

We would like to thank IMS Health-Canada and IMS Health-America for providing us with unrestricted access to the data required for the analyses. We would also like to thank the IMS analysts in Canada (Dorothy Rhodes) and the United States (Adrienne Stanere) who collated and formatted the data, and in particular, Daria Parsons and Dr. John Sampalis of IMS Health-Canada for facilitating data access and providing comments on earlier versions of the manuscript.

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    Drs. Majumdar and McAlister are Population Health Investigators supported by the Alberta Heritage Foundation for Medical Research, and New Investigators supported by the Canadian Institutes of Health Research. Dr. Soumerai is an Investigator in the HMO Research Network Center for Education and Research in Therapeutics, supported by the U.S. Agency for Healthcare Research and Quality (grant U18H510391) and the Harvard Pilgrim Health Care Foundation.

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