Reason
#1: The calculators ask for inputs on current cholesterol levels
rather than asking about your lifetime eating habits.
All
of about 8 or 9 online heart risk calculators I've looked at ask for
your current total cholesterol level and the level of your HDL or
“good” cholesterol. There are some big problems with doing that.
The first is that a large fraction of all people don't remember what
their latest HDL reading was. If you are like most people over 50,
you probably remember whether your latest cholesterol reading was
above 200, but don't remember what your HDL reading was. In such a case you will be unable to proceed when you come to a calculator such
as the calculator here.
Another
problem is that your latest cholesterol reading may not be a very
good indicator of your current eating habits. Many people alter their
eating habits in the weeks before taking a scheduled blood test, in
hopes of getting a better cholesterol reading.
A
third reason is that your heart attack risk depends relatively little
on your current cholesterol level, and more on your lifetime eating
habits. A heart attack can occur when plaque builds up in your
arteries. The likelihood of that happening depends on your eating
habits over the past few decades. Let's imagine two people, Ed and
Sam, both age 60. Ed has been eating tons of red meat for four
decades, but in the past year has reformed his eating habits, and
brought his total cholesterol down to 200. Sam for the past 40 years
has been eating little food high in bad cholesterol, and lots of food
high in good cholesterol. But in the past year he's slipped a little,
and his total cholesterol is now 220. Which has a higher chance of
heart attack? It's Ed, not Sam, despite Ed's current lower
cholesterol – because your lifetime eating habits determines how
much plaque is in your arteries.
It
would seem that rather than asking about your latest cholesterol
reading (requiring an HDL number you probably don't know), our heart
risk calculators should instead be asking about your lifetime eating
habits.
Reason
#2: None of the calculators has an input for resting heart rate.
There
have been many scientific studies indicating that a person's resting
heart rate has a large effect on a person's chance of having a heart
attack or suffering sudden cardiac death. In the large Framingham
heart study, the average resting heart rate for a male was 64 beats
per minute. A much larger FitBit data set (derived from millions of users of
FitBit devices) suggests that the average heart rate for male 60-year-olds
in the US was about 62 beats per minute. But what if your resting
heart rate is 70 beats per minutes or 80 beats per minute or 87 beats
per minutes? According to numerous studies such as this one, your risk of heart
failure or sudden cardiac death is much higher – perhaps as much as
300% higher for someone with a heart rate greater than 85 beats per
minute.
Given
the significance of heart rate, and the ease in which anyone can get
their own resting heart rate by holding their wrist and using a
clock, there would seem to be no excuse for not having a heart rate
input slot on every online heart risk calculator. But how many such
calculators have such a thing? None of them do.
Reason
#3: Most of the calculators don't allow you to specify whether you
have a family history of heart disease.
Most
of the online risk calculators use what is called the ASCVD
algorithm, and such calculators do not ask you whether you have any
family history of heart disease. For example, the first calculator I
get when I do a Google search for “heart risk calculator” is a
calculator that does not ask me for whether anyone in my
family had a heart attack.
But
there is one online heart risk calculator that uses the “Reynolds
risk” formula for computing heart risk, and that calculator does
ask me “Did your mother or father have a heart attack before age
60?” When I choose “Yes,” my calculated 10-year heart attack or
stroke risk jumps from 8% to 13%. So evidently whether your father or
mother had a heart attack before 60 is a big factor that can affect
your heart risk by as much as 40%. So why do the vast majority of
online heart risk calculators not allow you to specify whether your
mother or father had a heart attack before the age of 60?
Reason
#4: None of the calculators allow you to specify whether you have a
diagonal earlobe crease.
A
diagonal earlobe crease is a line that some people have going across
their earlobes. It looks like this:
Quite
a few scientific studies have shown that if you have a diagonal
earlobe crease on both ears (called a “bilateral” earlobe
crease), the chance of you having cardiovascular disease is much
higher. For example, this 1982 study was based on exact measurements
of the artery health of 340 people, using coronary arteriography.
The study found that having a diagonal earlobe crease has a positive
predictive value of 91% for coronary artery disease, meaning if you
have the diagonal earlobe crease you are 91% likely to have coronary artery disease.
A similar 2004 study of 415 people (also using exact artery
measurements though angiography) found that having the diagonal
earlobe crease had a positive predictive value of 89% for coronary
artery disease.
Clearly
all of our heart attack risk calculators should have an input
allowing you to specify whether you have an earlobe crease. But none
of these calculators has such an input.
Reason
#5: None of the calculators has an input asking about your exercise
levels.
How
much a person exercises can affect his risk of having a heart
attack. It will come as little surprise that not exercising at all
will increase your risk of a heart attack. But what is surprising is
that a major study found that those who exercise very heavily may
have a much higher risk of heart attack. Such is the finding of the
very large CARDIA study. The Science Daily site reports this finding
with the headline, “Physically active white men at high risk for
plaque buildup in arteries.” The site states, “White men who
exercise at high levels are 86 percent more likely than people who
exercise at low levels to experience a buildup of plaque in the heart
arteries by middle age, a new study suggests.”
Clearly,
a decent heart attack risk calculator should have an input for how
much you exercise. But none of the online calculators has such a
thing.
Reason #6: None of the calculators has an input asking about how much time you spend sitting.
It is sometimes said, "Sitting is the new smoking," because too much sitting can cause an increased chance of heart attack. A 2015 meta-analysis on the association between heart risk and sitting found an association, but a pretty modest one, with a hazard ratio of 1.143, meaning lots of sitting might cause a 14% higher chance of a heart attack. But a 2012 meta-analysis found a much larger risk, finding that those who sit the most can have "a 147% increase in the RR [relative risk] of cardiovascular events." Clearly a question on how long you spend sitting each day should be included in a heart risk calculator. None of them currently has such a thing.
Reason #7: None of the calculators has an input asking about how much time you spend standing at work.
Given the information just discussed, you will be surprised to read the following quotes from a scientist who summarizes a large study done by he and his colleagues:
We found that people who primarily stand on the job are twice as likely to develop heart disease as people who primarily sit....In fact, the incidence of heart disease among those respondents who stood a lot at work (6.6 per cent) was similar to the incidence of heart disease among workers who smoked on a daily basis (5.8 per cent) or those who were obese (6.9 per cent).
What a decent heart attack risk calculator would look like
Based on all these considerations, I can show what a good heart attack risk calculator would look like. It would look like the page below, a page looking very different from all existing heart attack risk calculators. Unfortunately I can give you no URL for a page that implements such a design. I hope someone with expertise in this field will one day implement such a calculator.
We found that people who primarily stand on the job are twice as likely to develop heart disease as people who primarily sit....In fact, the incidence of heart disease among those respondents who stood a lot at work (6.6 per cent) was similar to the incidence of heart disease among workers who smoked on a daily basis (5.8 per cent) or those who were obese (6.9 per cent).
What a decent heart attack risk calculator would look like
Based on all these considerations, I can show what a good heart attack risk calculator would look like. It would look like the page below, a page looking very different from all existing heart attack risk calculators. Unfortunately I can give you no URL for a page that implements such a design. I hope someone with expertise in this field will one day implement such a calculator.
No comments:
Post a Comment