New Cholesterol Guidelines Mean Statins for Everyone
By: David A Fein, MD
For many years Americans have been told that you need to “know your number”. The number in question was your cholesterol level. Knowing your cholesterol level was supposed to be the first, and most important, step in measuring your risk of heart attacks and strokes.
In November, 2013, the American Heart Association and American College of Cardiology released a new update to the cardiovascular prevention guidelines that have upended the way we determine cardiovascular risk, downplayed the significance of your cholesterol level and created a storm of controversy over the way the new guidelines could lead to many more people being told to take cholesterol lowering drugs.
Under the old guidelines, your doctor relied upon a fairly simple point scoring system to first determine an estimate of your risk of a heart attack over the next 10 years. Factors such as age, blood pressure, smoking history, family history, HDL cholesterol levels and the presence of known vascular disease such as prior heart attacks were included in the calculation. You were considered “low risk” if your heart attack risk was calculated at less than 10% over the next 10 years and “high risk” if your heart attack risk was greater than 20% over the next 10 years.
If you were “low risk”, an LDL level below 160 was acceptable and you didn’t get started on medication unless you were over 190. If you were “high risk”, you got medication if your LDL was above 100. For those in between, an LDL of 130 or less was acceptable.
The new guidelines essentially do away with almost all of the reliance on LDL cholesterol. Instead, the decision about who needs treatment is based almost entirely on the risk level itself. And, the risk level criteria have also been lowered, making many more people eligible for drug treatment.
The new guidelines use a different risk calculator (you can download the risk calculator spreadsheet HERE to see your risk level) that is more complex and is not easily done without computer assistance and a spreadsheet. Many experts have criticized the new calculator as over-estimating risk levels. In part, this is because the new calculator includes stroke risk along with heart attack risk.
The major difference comes in where the new guidelines recommend starting drug therapy with a statin (which includes drugs such as Crestor or Lipitor). Statin therapy is recommended for the following groups:
People without cardiovascular disease who are 40 to 75 years old and have a 7.5% or higher risk for having a heart attack or stroke within 10 years.
People 21 and older who have a very high level of LDL cholesterol (190 mg/dL or higher).
People with Type 1 or Type 2 diabetes who are 40 to 75 years old.
People with a history of a cardiovascular event (heart attack, stroke, stable or unstable angina, peripheral artery disease, transient ischemic attack, or coronary or other arterial revascularization).
There is not much argument about the last group in this list. If you have documented cardiovascular disease you need to be treated.
People with diabetes have long been considered to be at high cardiovascular risk and are often put into the same risk category as people who have already had a heart attack. However, several published studies have found that those patients who have diabetes but no evidence of plaque in the coronary arteries on a CT Heart Scan are at no higher risk than the non-diabetic population. So, our recommendation is that diabetics with good blood sugar control should have a CT heart scan done to better define their cardiovascular risk before instituting drug therapy.
The biggest controversy surrounds the first group in the recommendations. The new guidelines recommend starting medication when your 10-year cardiovascular risk exceeds just 7.5%. Under the old guidelines, this would have still been considered a low risk level and unless your LDL level was very elevated you would not require medication. Under the new guidelines, even if your LDL level is low but your 10-year risk is over 7.5%, you are getting a prescription for a statin.
The problem is that all cardiovascular risk calculators are really just surrogate measurements of your age. Take any combination of risk factors and plug them into the calculator. You will find that just changing your age has a huge impact on the result. For example, a 40 year old non-smoking white male with a total cholesterol of 200, HDL of 40, normal blood pressure and blood sugar has a 10 year risk of 1.0%. No treatment needed. Now make him 65 years old without changing any of the other risk factors and his 10-year risk jumps to 11.4%. Now, he gets medicated. That effectively means that everyone will gradually age to a level where their risk calculation exceeds 7.5%, regardless of their other risk factors. Live long enough and you always end up on a statin under the new guidelines.
Another problem with relying solely on the risk calculator is that it relies on a statistical prediction that applies well to a group of people with comparable risk factors but has little meaning for any specific individual. We often see patients with multiple risk factors who undergo a CT Heart Scan and turn out to have no detectable plaque in their arteries. Those patients are actually at very low cardiovascular risk. Conversely, patients with no risk factors often turn to have extensive disease on their scans and are considered high risk. So, relying solely on the risk calculator will invariably mean treating some people who don’t currently have any coronary disease while not treating many people who already have a lot of plaque in their arteries.
Statin medications are clearly the best pharmacologic treatment available for reducing cardiovascular risk and will continue to play a critical role. But, the net effect of the new guidelines may be to increase the pressure on physicians to rely on statin medications in place of assisting patients with achieving healthier lifestyles that have been shown to be equally important in reducing cardiovascular risk. With the new guidelines, once your 10-year risk exceeds 7.5% your doctor may feel obligated to prescribe a drug regardless of how improvement in lifestyle factors may be achievable. Cardiac CT Scans may help to avoid treatment for patients whose risk can be shown to be less than the risk calculator predicts and may also help to identify those who need treatment because they are developing vascular disease despite the absence of risk factors. It will be interesting to see what other unanticipated effects the new guidelines may have as they are put into wider practice.