Preventive Statin Use Recommended by US Task Force
The US Preventive Services Task Force (USPSTF) in November 2016 became the latest in a string of organizations to recommend wider preventive use of statins for otherwise healthy individuals based on their risk of a heart attack or stroke.
The USPSTF guidance, which was based on a systematic review of the literature, reflects a growing consensus in medicine that the potential benefits of preventive statin use likely outweigh the risks for patients who meet certain criteria. The USPSTF recommendations are very similar to those from the 2013 American College of Cardiology/American Heart Association (ACC/AHA) guideline, which initially proved controversial because of a shift from cholesterol targets to risk-based eligibility for statins. This change led to an increase by millions in the number of US individuals who were eligible for preventive statins.
Since then, other groups have also recommended wider use of the medications to prevent heart attacks and strokes, including the Joint British Societies, the Department of Veterans Affairs, the Canadian Cardiovascular Society, and the UK National Institute for Health and Care Excellence.
“It’s reassuring that groups that used similar methodologies and the highest quality of evidence came to independent but remarkably similar conclusions,” said Donald Lloyd-Jones, MD, a coauthor of the 2013 ACC/AHA guideline and chair of the department of preventive medicine at Northwestern University in Evanston, Illinois.
A Cautious Approach
Although the guidelines are converging on a similar approach for preventive statin use, there are minor differences in the recommendations with respect to patient age, risk thresholds, and statin intensity.
The USPSTF recommended preventive statin use for individuals between the ages of 40 and 75 who have a risk factor for cardiovascular disease such as high blood pressure and 10% or greater 10-year calculated risk of a cardiovascular event. The USPSTF recommends using the 2013 ACC/AHA Pooled Cohort Equations to calculate 10-year risk of cardiovascular disease events, which is available online and as an app (http://www.cvriskcalculator.com/). It also suggested that such preventive therapy should be considered and discussed with individuals in that age range who have a cardiovascular risk factor and calculated risk between 7.5% and 10%.
“There is a greater net benefit for those in the 10% risk category,” explained the task force chair Kirsten Bibbins-Domingo, MD, PhD, MAS, who is a professor of medicine, epidemiology, and biostatistics at the University of California–San Francisco.
The recommendation is less aggressive than the 2013 ACC/AHA recommendations, which recommended a 10-year absolute cardiovascular disease risk threshold of 7.5% and suggested consideration of statin use for those at 5% to 7.5% risk.
One reason cited by Bibbins-Domingo for the more conservative targets was evidence that the ACC/AHA Pooled Cohort Equations may overestimate risk in some populations, especially in patients at the lower end of the risk spectrum.
“This is the tool that is available,” said Bibbins-Domingo. “Until we have a better tool, clinicians need to be aware there may be an overestimation of risk.”
But Lloyd-Jones said that there is recent evidence supporting the validity of the tool in representative populations. He emphasized that ultimately clinicians and patients, rather than the equations, must make the final decision.
“The equations are a good place to start the discussion,” he said.
The task force concluded that there was insufficient evidence to recommend preventive statins for those age 76 years and older. Some trials have shown a benefit such as the PROSPER (Pravastatin in Elderly Individuals at Risk of Vascular Disease) and HOPE 3 (Heart Outcomes Prevention Evaluation-3) trials, Lloyd noted. In older patients, he said the ACC/AHA recommended an individualized decision-making process. He noted that in some cases, older patients might have other conditions that take priority over preventive therapies.
Another difference was that the task force recommended a low- to moderate-intensity statin dose, whereas the ACC/AHA recommended a moderate- to high-intensity dose. Although statins are relatively safe, Bibbins-Domingo said, potential harms such as reversible myalgia and diabetes mellitus have been seen with higher doses.
“We think it provides the best balance of benefits to harms,” she said. She noted the recommendation does not preclude physicians from choosing higher doses.
Lloyd-Jones, however, argued that based on the designs of the trials done so far, the strongest evidence supports the use of higher doses.
“I continue to say that moderate- to high-intensity statins are more appropriate and only reduce the dose for those who can’t tolerate it,” he said.
Still, Lloyd-Jones emphasized how similar the 2 recommendations are.
“Making treatment decisions based on risk rather than LDL [low-density lipoprotein] levels is an important step forward,” he said. “[The USPSTF] adopted that framework.”
For both physicians and patients, wider use of statins represents a large paradigm shift. So far, use in some populations who could benefit has been lower than hoped, Bibbins-Domingo noted.
“This is change and change is hard,” Lloyd-Jones said. He explained that many clinicians were trained to focus on lowering cholesterol but are now being asked to embrace the use of risk-based treatment.
There are tools to help physicians identify patients who might benefit from statins. In addition to the ACC/AHA 10-year risk calculator app, many electronic medical record systems have built in 10-year risk calculators that will automatically assess patient risk on the basis of data in the system, Lloyd-Jones noted.
Bibbins-Domingo said the task force hopes that its recommendations and the convergence among guidelines targeting both specialists and primary care physicians will help boost the appropriate use of statins.
“This should allow generalists and specialists to have a similar approach for most patients,” she said.
Cardiologists have an important role to play in helping increase preventive use of statins among their primary care colleagues.
“We need to get this out to primary care doctors who are on front lines,” said Lloyd-Jones. “We need to do a better job.”
Both the ACC/AHA and USPSTF guidelines strongly recommend that patients be engaged in a shared decision-making process with the clinician about whether they would like to take statins.
“We agree that all this has to be done in the context of a discussion about the overall net expected benefit from a stain,” Lloyd-Jones said. That discussion needs to include patient’s risks, potential side effects, and patient preferences. n
Circulation is available at http://circ.ahajournals.org.
- © 2017 American Heart Association, Inc.