Straight Talk | Prevention Guidelines: The Good, the Bad, and the Ugly

By Steve Nissen

Editor’s Note

The new ACC/AHA Prevention Guidelines released in November at the American Heart Association 2013 Scientific Sessions in Dallas caused something of a stir in the wider cardiology community. In particular, the Blood Cholesterol guidelines and an updated risk calculator for assessing atherosclerotic cardiovascular risk in adults were widely discussed in both scientific circles and in the lay press. CSWN has culled excerpts from the perspective of several different cardiologists to reflect the diversity of opinions on this issue. Click the links to hear voices from the debate, and read Steve Nissen’s full commentary below.

Harlan Krumholz, MD: What to Know About the New Lipid Guidelines

Nathan Wong, PhD: New Guidelines Focus on Treating the Whole Patient, Not Just a Number

Seth Martin, MD: How About a Worldwide Effort to Collaborate on Developing Guidelines?

Erin Michos, MD: The New 2013 Risk Prediction Calculator: More Flawed Than the Old Calculator?

The release of the new ACC/AHA Prevention Guidelines in November 2013 has generated more controversy than any clinical practice recommendations in recent memory.1 The implications of these guideline on society are profound, affecting tens of millions of Americans—which likely explains the intense public and scientific scrutiny. A critical analysis of the guidelines reveals several areas of broad consensus (the “good”), some concerns over the development process and release (the “bad”), and more serious criticism of the approach used to select primary prevention patients for treatment (the “ugly”).

First, the good: Many of the recommendations are non-controversial. The focus on the exclusive use of statins (and not other agents) to treat patients at high risk is sensible, courageous, and evidence-based. Also scientifically sound are the recommendations to treat all patients with an LDL-cholesterol (LDL-C) >190mg/dL and the advice to administer statins to all type II diabetics and patients with existing cardiovascular disease.

Next, the bad: The guideline writers decided to completely eliminate target levels for LDL-C. Even the most vocal critics understand the scientific rationale for such a recommendation, but the approach represents a tectonic shift in public policy. For two decades, we have advised physicians to “treat to target” and patients to “know your numbers.” Now, with no prior warning, the guidelines abruptly recommend abandoning titration of therapy to reach specific LDL-C goals. There are essentially two categories of patients: those for whom moderate statin treatment is recommended (30-50% LDL lowering) and those for whom intensive lowering is recommended (>50% lowering).

The guidelines authors correctly note that clinical trials studied specific dosages of statins, not precise LDL-C targets. However, there is also clinical trial evidence suggesting that patients achieving lower LDL-C levels experienced better outcomes. Furthermore, strong genetic evidence links lifetime levels of LDL-C to the risk of morbid-mortal cardiovascular events. From a practical perspective, many clinicians employ LDL targets as a means to motivate patients and improve compliance. Accordingly, the abandonment of LDL targets represented the triumph of scientific purism over practicality. Right or wrong, we cannot expect primary care physicians (and patients) to abruptly abandon an approach used for more than 20 years. Physicians will not stop checking LDL levels and will continue to adjust medications in patients with persistently high values.

The process used to develop and release the guidelines also represents a source of concern. The National Institutes of Health (NIH), which has traditionally developed lipid guidelines, initiated the current effort 5 years ago, apparently underfunded because of the chronic budget battles in Congress. Then, with the document essentially complete, the NIH withdrew from the project—for reasons that have not been adequately explained—and transferred oversight to the ACC and AHA. The guidelines evolved with an excessive degree of secrecy and no opportunity for open public discussion.

Alternatively, the Preventive Services Task Force routinely pre-releases guidelines for a public comment period. New prevention guidelines affecting tens of millions of Americans should have undergone such a period of review and open comment, perhaps with public hearings to allow all sides to express their perspectives. That is how you build confidence and consensus.

Finally, the ugly: For adults without diabetes or heart disease, the guidelines use a new “risk calculator” and recommend statin treatment for individuals with a calculated 10-year risk greater than 7.5%. That represents a huge expansion of patients for whom treatment is advised. However, the new calculator was not previously published and immediately drew intense criticism claiming that that the calculator greatly overestimates risk.2 Testing the new calculator was an eye-opening experience for many practitioners, including me. Three sample patients are shown in FIGURE 1.

Figure 1
Patient Description Calculated Risk
A 47-year-old nonsmoking, nondiabetic African-American man with no family history of CHD, a total cholesterol of 160 mg/dL, LDL 88 mg/dL, HDL 44 mg/dL, systolic BP of 130 mmHg on 25 mg hydrochlorothiazide 7.6%
A 58-year-old nonsmoking, nondiabetic white man with no family history of CHD, total cholesterol of 164 mg/dL, LDL 92 mg/dL, HDL 42 mg/dL, systolic BP of 136 mmHg on no medications 7.5%
A 44-year-old nonsmoking, nondiabetic white man with strong family history of MI, total cholesterol of 250 mg/dL, LDL 182 mg/dL, HDL 28 mg/dL, systolic BP of 120 mmHg on no medications 5.0%

For the first two patients, it seems unlikely that cardiovascular practitioners would recommend a statin. For the third patient, it seems unimaginable to defer treatment in the presence of an LDL-C of 182mg/dL, an HDL of 28mg/dL, and a strong family history.

Where do we go from here? It makes the most sense to suspend implementation of the new prevention guidelines to allow a period of open discussion about the advantages and disadvantages of the proposed approach. The new risk calculator should be published in a peer-reviewed journal so that independent physician-scientists can evaluate its accuracy. A pause now will increase the likelihood of broad public acceptance of the prevention guidelines. A slowdown now will pay substantial dividends in the future.


References

1. Stone NJ, Robinson J, Lichtenstein AH, et al. J Am Coll Cardiol. 2013 November 7. [Epub ahead of print]
2. Ridker PM, Cook NR. Lancet. 2013;382:1762-5.

Clinical Topics: Dyslipidemia, Prevention, Lipid Metabolism, Nonstatins

Keywords: Heart Diseases, Risk, Public Policy, Cholesterol, LDL, Diabetes Mellitus, Primary Prevention, Consensus


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