Monday, August 18, 2014

ACC/AHA cholesterol guideline: summary and perspectives

- Kenny Lin, MD, MPH

As previewed in a previous blog post, the August 15th issue of AFP features a concise summary of the American College of Cardiology / American Heart Association updated cholesterol treatment guideline. Key points include an expansion of the role of statins in the primary prevention of atherosclerotic cardiovascular disease (ASCVD); elimination of specific low-density lipoprotein cholesterol (LDL-C) target levels; and a new tool for assessing of 10-year and lifetime risk for ASCVD. An accompanying POEM notes that full implementation of the new guideline would increase the number of U.S. adults eligible to take statins by nearly 13 million, with the percentage of adults 60 to 75 years of age for whom statins are recommended rising from 47.8% to 77.3%.

Two editorials in the same issue further explore the implications of the new guideline. Writing for the members of the guideline panel, Dr. Patrick McBride and colleagues emphasize that the recommendations are largely based on high-quality evidence from randomized controlled trials that measured patient-oriented outcomes. They argue that "these changes should simplify the approach to clinical practice by reducing titration of medication, the addition of other medications, and the frequency of follow-up laboratory testing." In a second editorial, Dr. Rodney Hayward concurs with the panel's decision to abandon LDL-C targets, but disagrees with setting a universal 10-year ASCVD risk threshold of 7.5% for treatment with a statin:

My biggest criticism of the new guideline is that it does not acknowledge a specific 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. It may be reasonable to set 7.5% as a starting point for discussion (e.g., for every 33 patients treated for 10 years, roughly one heart attack will be prevented [i.e., number needed to treat = 33]). But these risks and benefits are estimates with a nontrivial margin of error. The guideline does note that shared decision making should be used, but it provides no clear direction on when statins should be recommended rather than just discussed.

A similar debate is taking place in the United Kingdom, where its National Institute for Health and Care Excellence (NICE) recently recommended offering a statin to all persons with a 10-year cardiovascular event risk of 10% or more. An editorial in BMJ observed that doctors need better shared decision making tools to help patients understand the tradeoffs involved in taking medications that have potentially large population health benefits but are unlikely to prevent a bad outcome in an individual patient:

Doctors are unlikely to start giving patients clear numerical information simply because they are told to do so. They might do so if NICE can recommend information tools with the same force as when it recommends drugs, and if it becomes as easy to give contextual numerical advice as it is to print a prescription. ... We will need better data, from bigger trials, and better risk communication than for conventional medical treatment. ... Without such innovation in the use of medical data, we can say only that statins are—broadly speaking—likely to do more good than harm. That is not good enough.

Have you already integrated the ACC/AHA cholesterol guideline into your practice? If so, how do you decide whether to "recommend" versus "discuss" statins with patients? If not, what reservations or workflow issues have prevented you from transitioning to the new guideline?

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