The Framingham Risk Calculator is a standard method used by many physicians to predict risk for heart attack or death from heart disease over a 10-year period. Low-risk is defined as <10% risk of heart attack or cardiac death over 10 years; high-risk is defined as 20% or more over 10 years; intermediate-risk is in between.
Let's put it to the test:
Amy is a 53-year old businesswoman. She is 5 ft 4 inches, weighs 150 lbs. Her father had a heart attack in his early 50s followed by the usual list of hospital procedures including bypass surgery at age 60.
What is Amy's risk for heart attack or death from heart disease over the next 10 years? If we enter her data into the Framingham risk calculator, the following result is returned:
Information about your risk score:
Total Cholesterol: 198 mg/dL
HDL Cholesterol: 74 mg/dL
Systolic Blood Pressure: 120 mm/Hg
On medication for HBP: No
Risk Score: 1% Means 1 of 100 people with this level of risk will have a heart attack in the next 10 years.
So, according to the Framingham calculation, Amy has <1% risk for heart attack or death from heart disease over the next 10 years. Most primary care physicians would, at most, prescribe a statin drug and talk about a reduction in saturated fat.
Thankfully, Amy didn't fall for that bit of conventional mis-information. She instead got a CT heart scan, principally because of her father's history. Her score: 117 . At age 53, this put her into 90th percentile, in the worst 10% of scores for women in her age group (50-55). By heart scan criteria, her risk for heart attack is probably more like 4-5% per year, or approximately 40-50% over the next 10 years.
Let's do just a bit more math. If Amy hadn't known about her heart scan score and no preventive action was taken, the expected progression of her heart scan scores would likely be:
Year 1: 152
Year 2: 198
Year 3: 257
Year 4: 335
Year 5: 436
Year 6: 567
Year 7: 737
Year 8: 958
Year 9: 1245
Year 10: 1618
In fact, given Amy's starting heart scan score of 117, it is highly unlikely that she survives the next 10 years without heart attack or a fatal heart event. Yet the Framingham risk calculator puts Amy's risk at less than 1%. Could anything be more wrong?
The folly of the Framingham calculator was highlighted by a recent publication from the large Multi-Ethnic Study of Atherosclerosis (MESA), in which 3600 women (45-84 years), all of whom fell into the "low-risk" category by the Framingham calculator--just like Amy--were tracked over approximately 3 3/4 years. This study generated several observations:
1) 30% of the "low-risk" women had positive heart scan scores.
2) 5% of the "low-risk" women had scores of 300 or greater (very significant for a woman). 8.6% of these women experienced a cardiovascular event like heart attack or death over the period. Women with a heart scan score of 300 or greater had a 22-fold greater event risk compared to women with zero heart scan scores.
3) Women with heart scan scores of 1 to 299 had a cardiovascular event risk of approximately 5-fold greater risk over the period.
Across the U.S., 90% of women younger than 70 years old fall into the Framingham "low-risk" category. Yet this fiction is accepted as the prevailing standard, along with LDL and total cholesterol, for determination of risk in women and men.
In my view, using the Framingham risk calculator is a misguided, misleading path, one that will mis-classify a substantial number of women who could otherwise be spared from heart attack and catastrophe.
By the way, Amy is also the Track Your Plaque program record holder (by percentage drop), with a 63% drop in heart scan score over a 15 month period.