The findings of a new study suggest that millions of Americans may be prescribed the wrong treatments for heart problems, exposing individuals to unnecessary risks.
Researchers from Stanford University warn that tools used by doctors to estimate the chances that someone may experience a heart attack, stroke, or other heart problems may be off by more than 20 percent, which could mean that 12 million Americans are prescribed the wrong drugs. The findings were published earlier this month in the Annals of Internal Medicine.
The study looked at data on 26,689 adults between the ages of 40 to 79, who did not have prior cardiovascular disease. The researchers sought to test and improve the accuracy of the pooled cohort equations (PCEs), which were provided along with the prevention guidelines for cardiovascular disease in 2013. The tools are used to estimate the risk of a future heart attack or stroke over the next 10 years.
“The 2013 PCEs overestimated 10-year risk for atherosclerotic CVD by an average of 20% across risk groups,” the researchers determined. “Approximately 11.8 million U.S. adults previously labeled high-risk by the 2013 PCEs would be relabeled lower-risk by the updated equations.”
Overall the findings indicate that the analytic tools tend to overestimate the risk of heart attack and stroke in patients. However, the researchers noted that African American patients were at a particularly high risk of misestimation by the estimate tools. The study found that it often underestimated their risk. The risk estimates were often off by extreme amounts, such as 70% less or 250% higher than those of white patients.
“Updating the 2013 PCEs with data from modern cohorts reduced the number of persons considered to be at high risk,” they noted in the study’s limitations. “Clinicians and patients should consider the potential benefits and harms of reducing the number of persons recommended aspirin, blood pressure, or statin therapy. Our findings also indicate that risk equations will generally become outdated over time and require routine updating.”
Cholesterol Drug Health Risks
There were questions when the new guidelines were first introduced, due to the large number of patients that would be prescribed cholesterol drugs like Lipitor and Zocor, which belong to a class of medications known as statins.
Statins are among the best-selling drugs in the United States, with $14.5 billion in combined sales in 2008. They use the liver to block the body’s creation of cholesterol, which is a key contributor to coronary artery disease. However, a number of studies have linked the drugs to an increased risk of potentially serious injuries, including muscle damage, kidney problems and diabetes.
All statins carry warnings about the potential risk of serious muscle injury, known as myopathy. The most severe form of the muscle damage is rhabdomyolysis, which may lead to severe kidney damage, kidney failure and death.
More recently, Lipitor, Crestor and other statins have been linked to an increased risk of diabetes, leading the FDA to require new warnings in February 2012 about potential impact the medications may have on blood sugar levels. Studies have suggested that otherwise healthy individuals who begin taking statins to reduce their risk of heart disease, may actually face an increased risk of diabetes, which itself increases the risk of cardiovascular disease.