When the American College of Cardiology (ACC) and American Heart Association (AHA) released guidelines in November 2013 for primary prevention of cardiovascular disease, healthcare professionals questioned the threshold for prescribing statins. They worried that too many people would take the drugs, and the medications would be costly.
Their concerns may not be warranted, however, based on a computer simulation model used by researchers to quantify the tradeoff between health benefits and health risks.
Lead researcher Ankur Pandya, PhD, of the Harvard School of Public Health, and colleagues found the threshold used in the ACC/AHA guidelines fit an acceptable cost-effectiveness profile. They published their results online in JAMA on July 14.
Under the ACC/AHA guidelines, adults between 40 and 75 who have a 10-year atherosclerotic cardiovascular disease (ASCVD) risk score of 7.5 percent or higher are recommended to receive statin treatment.
The ASCVD risk score is calculated using traditional cardiovascular disease risk factors, including age, gender, smoking status, history of diabetes, systolic blood pressure, high-density lipoprotein cholesterol and total cholesterol. Pandya said healthy adults older than 40 should have the risk factors assessed every four to six years to determine if statins for primary cardiovascular disease prevention should be recommended.
“There’s a lot of controversy around that [7.5 percent] number, in particular, like, ‘Where did this come from?,’” Pandya told Cardiovascular Business. “There’s no trial that directly informed that number…Our analyses really did support the guidelines and the treatment threshold that they picked.”
In their computer model, the researchers evaluated 12 ASCVD thresholds ranging from no risk (which meant to treat everybody with statins) to a 100 percent risk (which meant to treat no one). They found that that a 7.5 percent threshold had an incremental cost-effectiveness ratio (ICER) of $37,000 per quality-adjusted life-year (QALY) gained, which was below the commonly used cost-effectiveness thresholds of $50,000 to $150,000 per QALY.
“Lower numbers are generally better when it comes to cost-effectiveness ratios,” Pandya said. “If the ratio is lower than the willingness to pay, it’s generally considered a good buy.”
The researchers also found even more lenient treatment thresholds (an ASCVD risk score of 3 percent or 4 percent) could be considered cost effective based on estimates health economists find acceptable. The incremental ICER was $81,000 per QALY for a 4 percent threshold and $140,000 per QALY for a 3 percent threshold.
If the guidelines shifted from a 7.5 percent threshold to a 3 percent or 4 percent threshold, meaning more people would receive statins, an additional 125,000 to 160,000 cardiovascular disease events could be averted over the course of the lifetimes of all U.S. adults, according to Pandya.
The costs associated with statin treatment include the cost of the drugs as well as the cost of the screening visit and cholesterol test. The model also considered the costs if patients had strokes, cardiac arrests or other events. In addition, the researchers accounted for costs associated with compliance in their model.
Pandya and colleagues have used the model since 2006 and updated it through the years. They originally used the model to assess the cost-effectiveness of hypertension guidelines in South Africa. In 2014, they used the model to examine the cost-effectiveness of laboratory testing for primary cardiovascular disease prevention.
“The model is this active model that we use for multiple analyses,” Pandya said. “We definitely plan to have more cost-effectiveness analyses of cardiovascular disease prevention strategies in the U.S. and globally.”