The authors say while guidelines look at the benefits of statins to prevent cardiovascular disease (CVD), they do not adequately assess the harms. The new model takes this into account.
The 2013 recommendation from the American College of Cardiology (ACC) and the American Heart Association (AHA) to use statins to prevent cardiovascular disease (CVD) for some adults with long-term risk kicked off a debate that has not stopped.
Despite support from the US Preventive Services Task Force (USPSTF), some physicians say the harms of statins outweigh the benefits for many patients, and too many patients complain of side effects. Now, a new analysis in the Annals of Internal Medicine supports this view—for too many patients, authors from the University of Zurich say, the benefits simply don’t outweigh the harms.1
The researchers, led by Henock G. Yebyo, MSc, conducted an extensive analysis based on mathematical modeling and concluded the 2013 guidelines should be revised to use much higher 10-year risk thresholds when recommending statins for prevention, and guidelines should be customized based on age, gender, and statin type.
An accompanying editorial supports the authors’ view: “The authors consistently found that the harms outweighed the benefits until 10-year CVD risk thresholds substantially exceeded those recommended in current guidelines,” the editorial stated. “The results paint a nuanced—if less optimistic—picture of the net benefits of statins, particularly in older adults who may not live long enough to benefit.”2
The ACC/AHA guideline called for use of statins for the primary prevention of CVD among adults with a 10-year risk of 7.5% of higher, based on the method of calculating risk contained in the guideline (which factored in age, blood pressure, cholesterol, and whether the person had diabetes). As this calculator has made its way into practice, there have been adjustments for patient preference and most recently for coronary artery calcium scores to guide decision making.
In 2016, the USPSTF recommended statins for primary prevention among adults whose 10-year CVD risk reached 10% and who had at least 1 other risk factor, while acknowledging statins could be acceptable at lower thresholds. This would have fewer people taking statins than under the ACC/AHA guideline but more than recommended before 2013.
The Swiss team performed a quantitative benefit-harm balance modeling study on the use of statins for primary prevention in persons aged 40 to 75 years who had no history of CVD events. The analysis focused on low- to moderate-dose statins, which are more frequently prescribed for primary prevention, and it extended the time horizon out to 10 years.
The results showed that current guidelines accurately account for benefits of statins but fail to fully account for harms; instead of taking statins at a risk threshold of 7.5%, they found that the proper threshold varied between 14% and 22%, depending on age and gender. Risks were lower for atorvastatin (Lipitor) and rosuvastatin (Crestor) than for simvastatin (Zocor) and pravastatin (Pravachol) across all age groups and for men and women, “indicating that they had a more favorable benefit-harm balance.”
“Guidelines emphasize benefits, and although harms are not ignored, they seem to have little effect on recommendations,” the authors wrote. “The problem with such an approach is that eligibility for statins increases with age because more events can be prevented in elderly persons who are at higher CVD risk.”
“However, when harm outcomes, which also increase with age, are considered, the benefit-harm balance of statins becomes less favorable.”
In other words, right now, anywhere from 50 to 200 people who don’t have CVD must take a statin to prevent just 1 heart attack over 5 years. Meanwhile, many of these patients will develop muscle pains and they are also at higher risk of developing type 2 diabetes.
The authors noted that, “Redefining the risk thresholds would have important clinical implications,” meaning far fewer patients would take statins, especially for pravastatin and simvastatin.
While there has been more discussion lately about shared decision making, the authors state, “none of the guidelines refer to a decision aid for fully informed decisions.” New cholesterol guidelines presented at the AHA Scientific Sessions do discuss shared decision-making, however.
The article included “heat maps” that could guide clinicians on ranges for guiding decisions.