Dr. K: Updated guidelines for statin use are controversial

In fact, there’s an old joke: Our faculty are so knowledgeable that, on any particular question, any three faculty are likely to have at least five completely different opinions — all strongly held and forcefully argued.

Not only is my answer going to be controversial, it also is going to be long. There is so much to say, I will need two columns to say it.

Statins are medicines that were developed to lower blood levels of low-density lipoprotein cholesterol (LDL cholesterol, or “bad” cholesterol). Statins were based on basic research that discovered how the liver controls the amount of LDL cholesterol in the blood. That research was honored with the Nobel Prize.

Subsequent studies proved that statins reduce the risk of heart disease. Most of us assumed that this was because they lowered LDL cholesterol. Guidelines were developed that said that people with LDL cholesterol above a certain level should take statins.

However, additional research revealed that it was not so simple. First, it was discovered that inflammation inside plaques of atherosclerosis raised the risk of heart disease. Then it was shown that, in addition to lowering cholesterol, statins also reduced inflammation.

A large study put the icing on the cake. It showed that statins reduced the risk of heart disease even in people with normal levels of LDL cholesterol — presumably by reducing inflammation. So there were two different ways (anti-cholesterol and anti-inflammation) in which statins could lower the risk of heart disease.

Based on this new information, updated guidelines published in 2013 moved away from recommending statins just for people who have high blood levels of LDL cholesterol. Instead, the new guidelines recommended a statin for anyone between 40 and 75 years of age who has a 7.5 percent or higher risk of having a heart attack or stroke over the next 10 years.

How do you calculate your risk? There are various different systems, and those systems were developed from studies of different populations of patients. All of the systems measure “risk factors” that previous research has shown increase the chances of developing heart disease — or of having more heart trouble if you already have heart disease.

In tomorrow’s column, we’ll talk about the risk factors and the controversy over prescribing statins based on those factors — and not just on a person’s blood level of LDL cholesterol.

Plus, I’ll answer your question as to what I think about the new guidelines. Just don’t tell my colleagues here at Harvard what I said.

(Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.)