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TWO WOMEN in their 60s have similar blood pressures and cholesterol levels (LDL and HDL) —variables used to assess the 10-year risk of heart disease in those with no prior heart attack or stroke by the various risk calculators.
Viewing scores from their demographics, labs and personal histories (diabetes and smoking), the physicians treating each woman prescribed cholesterol-lowering statins. But then Woman#1 found a new doctor, who reviewed her numbers, considered the statin side-effects of muscle pain that she’d experienced and took her off the drugs.
Prescribing guidelines recommend statins when the 10-year risk of developing Atherosclerotic Cardiovascular Disease (ASCVD) is 7.5% and over—though that can vary between 5% and 10%—for patients 40 to 75 years of age, with no clinical heart disease or diabetes, and whose LDL cholesterol levels range from 70 to 189 mg/dl.
The algorithm used by the ASCVD Heart Risk Estimator focuses on variables that can be controlled: levels of cholesterol and blood pressure, as well as smoking and uncontrolled diabetes. Like most calculators, however, it doesn’t add in important variables such as diet, exercise, obesity, and “uncontrolled stress and anger,” as listed by WebMD.
The crucial element missing from most algorithms is family history. Woman#2’s father died from a heart attack at age 60; Woman#1 not only had a family history without heart disease but her own cholesterol levels had been very good until a bout with Lyme disease caused a puzzling and dramatic rise in her late 50s.
Of the 20 or so calculators currently in use, most are based on the Pooled Cohort Equations (PCE) published in 2013, but a recent NIH-funded study found the results to be “way too high or low for some patients,” according to Stanford University professor Sanjay Basu, lead author of the study.
The PCE overestimated heart disease risk in about 20% of individuals –- indicating approximately 11.8 million fewer Americans at risk than originally determined, Basu told Medscape Medical News. This finding “substantially” reduced the numbers of people who should be taking statins or antihypertensive agents or even aspirin.
Over-estimations occurred most often in older persons without long-standing risk factors; those with a ten-year risk below 10%; and those with higher socioeconomic status who were more likely to have a healthy lifestyle and be on preventative drug therapy, according to a 2018 special report from the American College of Cardiology (ACC) and the American College of Cardiology and American Heart Association (AHA).
Under-estimations were most likely in African Americans as well as in those with family histories of chronic kidney disease, chronic inflammatory diseases and premature vascular disease—as in the case of Woman #2.
In ASCVD, cholesterol plaque buildup in the arteries leads to heart attack, stroke, peripheral artery disease and other heart issues. The current guidelines also recommend cholesterol-lowering treatment in those with clinical ASCVD—those with LDL levels above 190 mg/dl, and those with diabetes and LDL levels 70 and above.
For women over 50 with borderline profiles —“moderate” risk levels between 5% and 7% and those with low scores who have a family history of heart disease—a heart scan can help determine the need for statins. Also known as a coronary calcium scan, this specialized X-ray of the heart detects and measures calcified plaque in the arteries.
Other red-flag markers for heart disease are high-sensitivity C-reactive protein (hsCRP), which has proved a better predictor for heart disease than LDL cholesterol; high HDL cholesterol, which can cause inflammation in the presence of dietary saturated fat; and insulin resistance as determined by high levels of HgA1c and fasting glucose.
To reduce ASCVD risk, cholesterol-lowering statins counter inflammation throughout the body, including the brain—which might also help protect against dementia. On the other hand, potential side effects include mental fuzziness along with muscle aches—most common in women age 65 and older with a small body frame. Rarely, statins can damage the liver and muscles.
Low-dose aspirin can protect against heart disease for adults with a ASCVD risk lower than the eligibility for statins—in the range of 6% to 10%. For patients older than 50 with no symptomatic ASCVD, the American College of Chest Physicians recommends aspirin, but most experts consider aspirin’s benefits outweighed by increased chance of GI and intracranial bleeding in those with lower risk levels and in anyone age 70 and older who hasn’t taken aspirin before.
Diet advice to counter heart disease risk changed dramatically with new guidelines published in 2015 from imposing an upper limit on cholesterol intake to a focus on trans fats—to be eliminated entirely—and saturated fats. For the latter, experts keep lowering the limits: from a recent general recommendation of 10% or less of daily calorie intake, to further limits from the AHA to 5% to 6% or less—which comes to about 100 calories in a diet of 2,000 calories/day.
Despite the usefulness of algorithms and calculators, talking to a doctor often provides the best assessment of individual risk. In the cases of the two women, each had a personal history—family and Lyme disease—that made the difference.
—Mary Carpenter
Every Tuesday in this space, well-being editor Mary Carpenter reports on health news you can use.