Blog | Thursday, November 21, 2013

Greatly improved new statin guidelines, with one exception


The Twitterverse blew up yesterday when they released the new lipid guidelines. I read many articles and finally think I am understanding the big progress these guidelines achieve.

My favorite review is on Medscape (free registration required) New Cholesterol Guidelines Abandon LDL Targets. I titled this post the statin guidelines, because these guidelines no longer focus on LDL levels, but rather the use of statins. We are no longer asked to treat to goal, rather to put appropriate patients on a statin.

“The four major primary- and secondary-prevention patient groups who should be treated with statins were identified on the basis of randomized, controlled clinical trials showing that the benefit of treatment outweighed the risk of adverse events. The four treatment groups include:

1. Individuals with clinical atherosclerotic cardiovascular disease.

2. Individuals with LDL-cholesterol levels >190 mg/dL, such as those with familial hypercholesterolemia.

3. Individuals with diabetes aged 40 to 75 years old with LDL-cholesterol levels between 70 and 189 mg/dL and without evidence of atherosclerotic cardiovascular disease.

4. Individuals without evidence of cardiovascular disease or diabetes but who have LDL-cholesterol levels between 70 and 189 mg/dL and a 10-year risk of atherosclerotic cardiovascular disease >7.5%.”

Obviously these groups differ in many ways from current guidelines. The writing panel acknowledged that they had no outcome evidence for any cholesterol lowering medication other than statins. So adding a second or third medication is no longer needed or desirable.

Group 1 is the most important because the benefit has the best evidence. For those patients, the new guidelines suggest either rosuvastatin or atorvastatin (high-intensity statins) unless not tolerated. They also recommend this strategy for the very high cholesterol patients (group 2).

For group 3 patients, they recommend moderate-intensity statins (we generally use pravastatin for price and less side effects).

Group 4 is a problem in my mind, and in the minds of some critics.

To heartwire, Dr. Roger Blumenthal (Johns Hopkins Medical Institute, Baltimore, MD), who was not part of the writing committee, said he agreed with 90% of the information in the new guidelines. “To put that in perspective, I probably only agree with my wife 85% of the time,” he said.

I don’t even agree with my wife 100% of the time.

Namely, he is a little troubled by the new atherosclerotic risk score. Derived from FHS, ARIC, CARDIA, and CHS, it hasn’t performed all that well when applied to other cohorts, such as the Multiethnic Study of Atherosclerosis (MESA) and Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, he said. The risk score does not take into account family history of premature cardiovascular disease, triglycerides, waist circumference, body-mass index, lifestyle habits, and smoking history.

“In my mind, we’re putting a lot of faith in this risk score,” said Blumenthal. “We’re probably going to be treating many more people, especially many more ethnic minorities, who get above this 7.5% threshold.”

Dr. Brendan Everett (Brigham and Women’s Hospital, Boston, MA) told heartwire that the expert panel is going “out on a limb” a little with regard to the new risk score. He said that while a risk-prediction algorithm was used in the ATP III guidelines, a number of large statin trials have been published to date, and none of these studies used a risk score to identify patients for inclusion.

“If the model performs poorly, of course, then it’s unlikely to do a good job separating patients at a higher rather than lower 10-year atherosclerotic cardiovascular disease risk, and it will thus lead to misallocation of statins,” commented Everett. “Even if it does perform well, using a risk score to identify individuals who will benefit from statin therapy, regardless of the etiology of their elevated risk, is not an approach that has been tested in any clinical trial.”

I downloaded the risk calculator yesterday. According the risk calculator I should have a statin discussion. My only risk are my age (64) and my Y chromosome. I get no credit for 0 family history, good waist circumference and regular exercise. I just do not believe the calculator.

I hope that when we translate this guideline into performance measures, we do not include group 4 – because we have no data to support its use. I have no problem doing primary prevention in patients with a very high risk, but believe that we should read the fine print very carefully here:

“In the primary-prevention-therapy decisions, we insisted that the patient and the physician have a discussion to determine what the benefits and risks are specifically for that patient,” said Stone. This discussion should focus on the patient’s characteristics and preferences to determine the best therapy.

Group 4 should not produce a performance measure. Rather these patients deserve thoughtful joint decision making.

Overall the panel deserves a strong B+. They could have received an A if they had not tried so hard to include large numbers of primary prevention patients.

db is the nickname for Robert M. Centor, MD, FACP. db stands both for Dr. Bob and da boss. He is an academic general internist at the University of Alabama School of Medicine, and is the Associate Dean for the Huntsville Regional Medical Campus of UASOM. He also serves as a frequent ward attending at the Birmingham VA Hospital. This post originally appeared at his blog, db's Medical Rants.