A move away from specific cholesterol treatment targets, assessment of both 10-year and lifetime cardiovascular disease risk, and inclusion of stroke in cardiovascular disease risk estimates are among the highlights of updated clinical practice guidelines on reducing cardiovascular risk released Nov. 12 by the American College of Cardiology and American Heart Association.
Written by the blood cholesterol expert panel that was originally the Adult Treatment Panel (ATP) IV, the cholesterol treatment guideline will inevitably receive the most attention, with the shift from recommending treatment of cholesterol to a specific LDL cholesterol target to treatment based on an increased risk for cardiovascular disease and stroke with medications proven to reduce those risks.
"Rather than LDL-C or non–HDL-C targets, this guideline used the intensity of statin therapy as the goal of treatment," identifying four groups of individuals "for whom an extensive body" of evidence from randomized controlled trials demonstrated a reduction in atherosclerotic CVD events "with a good margin of safety from moderate- or high-intensity statin therapy," the panel concluded. While these guidelines are a change from previous guidelines, "clinicians have become accustomed to change when that change is consistent with the current evidence," they added.
The cholesterol treatment guideline provides "a new perspective on LDL and non-HDL treatment goals," with the identification of the four groups of patients for whom moderate- or high-intensity statin treatment is recommended, for primary or secondary prevention, explained Dr. Neil J. Stone, chair of the writing committee. "Despite an extensive review, we were unable to find solid evidence to support continued use of specific LDL-cholesterol or non-HDL treatment targets," he said in a telephone briefing.
The previous guidelines recommended treating to an LDL goal of below 100 mg/dL in people at high cardiovascular risk, but also recommended a goal of 70 mg/dL or lower for patients at very high risk.
The four sets of clinical practice guidelines were initially commissioned by the National Heart, Lung, and Blood Institute (NHLBI) in 2008, and were transitioned to the AHA and ACC earlier this year. On the basis of evidence from the best clinical trials and epidemiologic studies through 2011, the "long-awaited" guidelines focus on assessment of cardiovascular risk, lifestyle modifications to reduce cardiovascular risk, and management of overweight and obesity in adults, in addition to management of blood cholesterol, Dr. John Gordon Harold, ACC president, said during the briefing.
The 2013 guidelines "will provide updated guidance to primary care providers, nurses, pharmacists, and speciality medicine providers on how to best manage care of individuals at risk of cardiovascular diseases," based on evidence available through 2011, said Dr. Harold of the David Geffen School of Medicine at the University of California and Cedars-Sinai Heart Institute, Los Angeles.
In the cholesterol treatment guideline, Dr. Stone said that based on an extensive literature review, the evidence supported the use of the "appropriate intensity" of statin therapy in addition to a heart-healthy lifestyle to reduce risk, with the identification of four "major statin benefit groups" for whom "high intensity" statin treatment (lowering LDL by at least 50%) or "moderate intensity" statin treatment (lowering LDL by roughly 30%-49%) is recommended. Those groups are patients with:
• Clinical atherosclerotic cardiovascular disease (ASCVD).
• A primary elevation of LDL-cholesterol of 190 mg/dL or higher, including those with familial hypercholesterolemia.
• Diabetes, aged 40-75 years with no clinical ASCVD and LDL levels of 70-189 mg/dL.
• No clinical ASCVD or diabetes, aged 40-75 years, with an LDL of 70-189 mg/dL and an estimated 10-year risk of ASCVD of at least 7.5% (determined by calculating the global cardiovascular risk assessment score, using formulas developed by the Risk Assessment guideline work group and included in that guideline).
"The idea was that certain groups such as those with [a prior atherosclerotic event] and those with very high LDL-cholesterol, especially these familial forms ... benefit most, if they can tolerate it, from high-intensity statin therapy." For those with a score of 7.5% or more, who have not had an MI or stroke, analyses provide strong evidence that treatment can forestall or prevent these events, and in those at high risk, "even can reduce total mortality," said Dr. Stone, Robert Bonow Professor in the division of medicine-cardiology at Northwestern University, Chicago.
Often, the use of a specific target might lead to undertreatment in certain groups, or overtreatment when, for example, additional medications that are not proven to add incremental or additional benefit are added to treatment. Rather than supporting a target, the data indicated that clinicians "use the appropriate intensity of statin therapy to reduce this atherosclerotic risk in those most likely to benefit," and that nonstatin therapies "didn’t provide an acceptable CVD risk reduction benefit compared to their adverse effects in the routine prevention of heart attack and stroke," Dr. Stone noted.