In November 2013 updated guidelines for the treatment of
high cholesterol were released by the American College of Cardiology-American
Heart Association. These guidelines were
the subject of significant controversy.
In contrast to the previous guidelines from 2002, the current guidelines do not
suggest treatment based primarily on numerical cholesterol targets. Rather, the
guidelines stratify people according to determined cardiovascular risk
and recommend either high intensity statin treatment, moderate intensity statin
treatment, or no statin treatment. The guidelines do not support using other types
of cholesterol-lowering drugs because at this point there is not good data to
suggest that using other types of treatments is beneficial in terms of
preventing actual cardiovascular outcomes (heart attack, stroke or
cardiovascular death). This is despite the fact that there are treatments out
there that do lower one’s cholesterol numbers.
How is cardiovascular risk determined? With the new
guidelines, a new risk calculator was proposed. In my clinical practice in the
past I’ve used the Framingham Risk Calculator
and the Reynolds Risk Calculator
. The new risk calculator released with the 2013 guidelines is a bit different.
Some experts have suggested that it overestimates risk. With the new risk
calculator, if one’s ten year risk of a cardiovascular event exceeds 7.5% then
treatment with a statin is recommended.
The new guidelines divide people into the following groups
of patients between ages 40 and 75 years who are in need of treatment with
statins, or so called “statin benefit groups.”
·
Those with LDL over 190mg/dL (high intensity statin
treatment is recommended)
·
Those with a ten year risk of >7.5% (moderate
intensity statin treatment is recommended)
·
Those with established cardiovascular disease
(high intensity statin treatment is recommended)
·
Those with diabetes, in which 10 year risk is
>7.5% (high intensity statin treatment is recommended)
·
Those with diabetes, in which 10 year risk is
<7 .5="" font="" intensity="" moderate="" statin="">treatment is recommended)
Click here to calculate your risk. What qualifies as high intensity statin treatment? LDL
lowering of 50% or greater. What is moderate intensity statin treatment? LDL lowering of
30-50%.
The guidelines suggest that particular statins may be better
than others at achieving these goals and good outcomes: atorvastatin,
simvastatin, and rosuvastatin. Other
statins are typically used when patients experience unwanted side effects, like
muscle pain.
How are things different with the new guidelines?
Let’s take an example.
A 71 year old white female, non-smoker,
non-diabetic, with a history of hypertension, asked me whether or not she
should be treated for high cholesterol. She is concerned about her risk of heart
disease, as her mother had a stroke in her 60s and then sudden death, presumed cardiovascular,
at age 83. My patient’s most recent total cholesterol level was 204 mg/dL with
an LDL level of 121 mg/dL and an HDL level of 64 mg/dL. A couple of years ago I calculated her
Framingham Risk score, which is 6% with these risk factors. This represents low
to intermediate risk. To get further information I also ordered a coronary
calcium score, which was found to be zero.
Last year, based on these numbers and the older guidelines, I
recommended against treatment with a statin. However, now, based on the new risk assessment
tool, the same patient has a ten year risk of 16%. With the new guidelines she would unequivocally
qualify for moderate dose statin. At
this point, I am not exactly sure what to do with the coronary calcium score,
which probably projects that her risk is lower than the 16% that the new
equation came up with. Nonetheless, I am
not sure that coronary calcium scoring entirely predicts all
cardiovascular risk—for example risk related to small vessel disease and
stroke, so perhaps she should receive treatment. Low dose, statin treatment might be a good
compromise here.
Interestingly, based on this new risk calculator virtually
every 71 year old, even with optimal risk factors, would qualify for treatment with
a statin. Herein lies the controversy
with this tool.
Nonetheless, my own view of the new guidelines is mostly favorable.
To me it simplifies things based on what we know from numerous well designed
studies. Treatment, with an emphasis on statins, is based on risk projection
and less attention is paid to absolute numbers. I hope that the next decade will continue to bring
more a nuanced understanding of risk.
