Editor's Note: Commentary based on Johansen ME, Green LA, Sen A, Kircher S, Richardson CR.Cardiovascular risk and statin use in the United States. Ann Fam Med. 2014 May-Jun;12(3):215-23..

Background

With the 2013 ACC/AHA cholesterol guidelines, the decision to initiate patients on statin therapy has shifted away from emphasizing lipid goals to place more emphasis than previously on patients' absolute cardiovascular risks. Johansen et al. hypothesized that the previous emphasis on hyperlipidemia for the initiation of statin therapy may have led to undertreatment with statins in high risk patients without hyperlipidema.¹ Thus, they examined the relationships between statin use in patients with known coronary artery disease or diabetes mellitus, diagnosis of hyperlipidemia, and high absolute cardiovascular risk.

Methods

Using nationally representative, self-reported, cross-sectional data from the 2010 Medical Expenditure Panel Survey (MEPS), the authors studied more than 16,000 individuals aged 30 to 79 years. Statin users were defined as individuals who reported filling two or more statin prescriptions from a pharmacy in 2010 (self-reported and confirmed with pharmacy data). Multiple logistic regression models for statin use as the dependent variable, with cardiovascular risk factors and sociodemographic factors as independent variables were created.

Results

After adjusting for cardiovascular risk and sociodemographic factors, the authors found that patients with self-reported coronary artery disease or diabetes mellitus were ~4-times more likely to receive statin therapy if they had concurrent hyperlipidemia. Extrapolating their results to the U.S. population, the authors estimated that 9.0 million people with diabetes older than 40 years and 5.6 million people with coronary artery disease were not receiving statins.

Conclusion

A potential benefit of the 2013 ACC/AHA guidelines is the increased emphasis on importance of global 10 year and lifetime cardiovascular risk assessment as the cornerstone of preventive care. This may offer an opportunity to avoid statin under-treatment in patients with high absolute risk but without overtly high lipids.

Commentary/Perspective

The 2013 ACC/AHA risk estimator has significant advantages over the risk score based only on the Framingham Heart Study, most notably inclusion of stroke as atherosclerotic outcome and distinct equations for previously underrepresented populations. Yet, the risk estimator is still based on the same traditional risk factors as before: age, total and HDL-cholesterol, smoking, diabetes mellitus, and systolic blood pressure / hypertension. However, in a recent study by Silverman MG et al., nearly one-third of high risk patients with three or more cardiovascular risk factors had a coronary calcium score of zero, which has a very strong negative predictive value for future cardiovascular events.² Likewise, it has been questioned whether all patients with diabetes mellitus are at equally high risk and derive benefit from aggressive secondary prevention measures.³ In this respect, the benefits and harms from risk factor modification have been shown to vary widely across the US diabetes population depending on a patient's underlying CVD risk, suggesting a personalized approach could maximize a patient's net benefit from treatment.³ Future studies will need to compare methods to assess risk based on inference from large populations to more individualized risk assessment strategies with direct measurement of subclinical atherosclerosis from novel risk markers such as coronary calcium score in individual patients.

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References

1. Johansen ME, Green LA, Sen A, Kircher S, Richardson CR. Cardiovascular risk and statin use in the United States. Ann Fam Med 2014;12:215-223.
2. Silverman MG, Blaha MJ, Krumholz HM, Budoff MJ, Blankstein R, Sibley CT, Agatston A, Blumenthal RS, Nasir K. Impact of coronary artery calcium on coronary heart disease events in individuals at the extremes of traditional risk factor burden: the Multi-Ethnic Study of Atherosclerosis. Eur Heart J 2013; [Epub ahead of print]. doi: 10.1093/eurheartj/eht508.
3. Timbie JW, Hayward RA, Vijan S. Variation in the net benefit of aggressive cardiovascular risk factor control across the US population of patients with diabetes mellitus. Arch Intern Med 2010;170:1037-1044.

Keywords: Cardiovascular Diseases, Cholesterol, Coronary Artery Disease, Diabetes Mellitus, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Hyperlipidemias, Risk Factors

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