Abstract

Background

Statins are prescribed to treat dyslipidemia (abnormal amount of lipids such as cholesterol and/or fat in the blood) and reduce cardiovascular disease (CVD) risk. This study describes the CVD risk profile of Canadians aged 20 to 79, compares current treatment patterns with guideline recommendations, and investigates the population health impact of statin treatment.

Data and methods

The baseline CVD risk of the Canadian population aged 20 to 79 was estimated by applying population-weighted risk factor data from the 2007 to 2011 Canadian Health Measures Survey (CHMS) to the Framingham Risk Score. Estimates of statin effectiveness from the literature were applied to baseline risk to assess the number of CVD events avoided owing to actual (CHMS-reported) and recommended (2012 Canadian Cardiovascular Society guidelines) statin treatment.

Results

An estimated 2.8 million Canadian adults (about 1 in 10) were treated with statin drugs. The mean 10-year CVD risk of those treated was 27%. Assuming optimal adherence, it was estimated that statin treatment avoided around 18,900 CVD events annually and yielded a number-needed-to-treat (average number of patients treated to prevent one additional CVD event) of 15 over 10 years. In comparison, 6.5 million Canadian adults (about  1 in 4) were recommended for treatment under the 2012 guidelines. The mean 10-year CVD risk of those recommended for treatment was 24%, which translates into a number-needed-to-treat of 17 over 10 years, or approximately 38,600 CVD events avoided annually. The largest gaps in treatment and potential CVD events avoided were among people at high and intermediate risk for CVD.

Interpretation

Canadians’ CVD risk could be lessened with enhanced targeting of statin treatment to individuals at high and intermediate risk. Such a strategy would likely require additional investments.

Keywords

Cardiovascular disease, clinical guidelines, risk assessment, risk reduction

Findings

Statins—drugs used to lower cholesterol—have been shown to improve survival and reduce the risk of cardiovascular disease (CVD) events among individuals across the spectrum of CVD risk. As a result, statins are one of the most frequently prescribed classes of drugs in Canada, and constitute the leading drug cost in all provincial drug programs, with direct drug costs totalling almost $2 billion annually. The prescribing of statins has not been without controversy. New guidelines on CVD risk assessment and statin treatment from the American College of Cardiology and American Heart Association and from the National Institute for Clinical Evaluation in the United Kingdom have brought the issue into the headlines. [Full Text]

Authors

Deirdre A. Hennessy (deirdre.hennessy@canada.ca) is with the Health Analysis Division at Statistics Canada. Peter Tanuseputro and Richard Perez are with the Ottawa Hospital Research Institute and the Bruyere Research Institute. Meltem Tuna is with the Ottawa Hospital Research Institute and the Institute for Clinical Evaluative Sciences. Carol Bennett is with the Ottawa Hospital Research Institute. Margot Shields is with the Public Health Agency of Canada. Dennis T. Ko and Jack Tu are with the Institute for Clinical Evaluative Sciences and the Schulich Heart Centre at the Sunnybrook Health Sciences Centre. Douglas G. Manuel is with the Health Analysis Division at Statistics Canada, the Ottawa Hospital Research Institute, the Bruyere Research Institute, and the Institute for Clinical Evaluative Sciences.

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What is already known on this subject?

  • Statins—drugs that lower cholesterol—have been shown to improve survival and reduce the risk of cardiovascular disease (CVD) events.
  • Statins are one of the most frequently prescribed classes of drugs in Canada, and constitute the leading drug cost in all provincial drug programs.
  • Little evidence is available to assess the population health impact of the use of statins.

What does this study add?

  • With data from the 2007 to 2011 Canadian Health Measures Survey, this study describes the CVD risk profile of Canadians aged 20 to 79, compares current treatment patterns with guideline recommendations, and examines the population health impact of statin treatment.
  • An estimated 2.8 million Canadian adults (about 1 in 10) were treated with statin drugs.
  • Assuming optimal adherence, statin treatment was estimated to have avoided around 18,900 CVD events annually, with a number-needed-to-treat (average number of patients treated to prevent one additional CVD event) of 15 over 10 years.
  • A treatment gap emerged for people at intermediate and high risk of CVD, which, if addressed, could avert an estimated 19,500 CVD events each year.

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