The Revised Cholesterol Guidelines

October 10, 2017

What about those patients who fall into the "gray zone"?

Numbers aren’t the end-all. That distills one of the key recommendations from the Blood Cholesterol Expert Panel of the American College of Cardiology (ACC) and the American Heart Association (AHA), when the ACC/AHA guidelines on the use of statins to lower the risk of atherosclerotic cardiovascular disease (ASCVD) in adults were published in 2013.1 The paradigm of using treatment targets of low-density lipoprotein cholesterol (LDL-C) had shifted with this publication. The authors recommended that clinicians consider risk groups, such as patients with diabetes mellitus or previous ASCVD.

The guidelines state that 4 groups of patients are most likely to benefit from statins:
• Patients with any form of clinical ASCVD
• Patients with primary LDL-C levels of 190 mg/dL or higher
• Patients with diabetes mellitus, 40 to 75 years of age, with LDL-C levels of 70 to 189 mg/dL
• Patients without diabetes, 40 to 75 years of age, with an estimated 10-year ASCVD risk of 7.5% or higher

I’m not staking out a position on these or other guidelines, but I want to offer a few observations and questions.

A pro and a con
While previous guidelines, such as the Adult Treatment Panel III (ATP III), advised treating patients to target levels of LDL-C, clinical trials of statins have not compared these ranges. Thus, the recommendations in the revised guidelines to treat based on cardiovascular risk are better supported by the evidence.

What about those patients for whom the advice to start a statin is less clear-cut: for example, a patient whose 10-year ASCVD risk may be slightly above 7.5%? This region is what Rodney Hayward, MD, terms a “gray zone-a range in which the potential benefits and harms of a statin make the ‘right decision’ predominantly a matter of individual patient circumstances and preferences.”2Knowledge deficits abound
Have physicians been agreeing with or implementing these guidelines in their practices? One study found that many physicians (52% of attendings and 57% of those in training) had not even read the revised guidelines-whether the entire document or the executive summary.3 These percentages were from a survey of endocrinologists, cardiologists, and family practice and internal medicine residents and attendings in 21 sites across the US.

Have these guidelines had an impact in the clinic? Have physicians changed their prescribing patterns? Tran and colleagues4 found that 1 year after these guidelines were released, there was no change in statin treatment rates in 2 groups of high-risk patients from a large health insurance organization. For those with ASCVD, the rate was 48% before the guidelines vs 47.3% after (standardized difference, 1.4%); for those with diabetes mellitus, the rate was 50% before vs 51.5% after (standardized difference, 2.4%).

What could be a way forward? It’s complicated
In addition to how to approach patients in the “gray zone,” other questions remain. The 10-year ASCVD risk calculator itself has not been studied. What about the role of PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors-for which more data will be forthcoming?

Dr Hayward notes:

Those who make guidelines and performance measures need to stop behaving as if primary care physicians need rigid rules for every decision, even those that are close calls. They need to recognize that for virtually every decision in life, there is a gray range in which the right decision is purely one of personal preference, a range in which they should defer to the primary care physicians who actually know the patient. The ACC/AHA committee . . . should now revise their guideline to specify a range in which the decision to start a statin should be tailored to the individual and not recommended by a central committee.2

What do you think? Where do you stand on these or other guidelines? What would you like to see included in the next iteration?

References:

1. Stone NJ, Robinson JG, Lichtenstein AH, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129(25 suppl 2):S1-S45.

2. Hayward RA. Should family physicians follow the new ACC/AHA cholesterol treatment guideline? Not completely: why it is right to drop LDL-C targets, but wrong to recommend statins at a 7.5% 10-year risk. Am Fam Physician. 2014;90:223-224.

3. Virani SS, Pokharel Y, Steinberg L, et al. Provider understanding of the 2013 ACC/AHA cholesterol guideline. J Clin Lipidol. 2016;10:497-504.

4. Tran JN, Kao TC, Caglar T, et al. Impact of the 2013 cholesterol guideline on patterns of lipid-lowering treatment in patients with atherosclerotic cardiovascular disease or diabetes after 1 year. J Manag Care Spec Pharm. 2016;22:901-908.