News

(Update: 1 p.m. Wall Street Journal Reporter Ron Winslow excels at writing about this topic. Read his science reporting on the importance of this study.)

This study shows that too many of the joint recommendations from the American College of Cardiology and American Heart Association are based on “lower levels of evidence” or “expert opinion.”

The authors recommend improving the process of writing guidelines and to expand the evidence base from which clinical practice guidelines are derived.

The good news?

This is an ideal example of science at work, questioning those experts who already have made recommendations.

Let’s use an every day example. Let’s imagine that heart disease, the leading cause of death for Americans, is, instead, a criminal.

Let’s imagine that the criminal is on trial.

Depending on the strength of the evidence against the criminal, the accused may end up in a federal penitentiary.

o Is the evidence hearsay from some witnesses who say they were at the scene? Not too strong. Witnesses have poor memories.

o Is the evidence hearsay, plus a gas station receipt one block from the scene of the crime and around the time of the crime? Getting stronger.

o What if the above evidence is capped off with footage from a bank security tape, which records the users’ faces at its outdoor ATM, stamped with date and time? Was the accused alone or with two friends? The ATM also was one block away from the scene of the crime? The evidence is much stronger in linking the perpetrator or perpetrators if there is direct, physical evidence, such as pictures, DNA traces, etc.

As you can see, each type of evidence is associated with a “confidence level.” How persuaded are you by the evidence? Weak? Strong?

Yes, witnesses are desirable, but they also can be confused by too many interviews or questions.  Lawyers and judges have some confidence in eyewitnesses, especially if there are several, but, as a rule, the confidence in this testimony is at a lower level than that of physical evidence from the crime scene.

When a patient is sitting in a doctor’s office discussing treatment, the doctor wants to be able to tell the patient what the confidence level is in recommending one form of treatment over another—the evidence. You want the best evidence possible at times like those.

Many times, doctors have to say, “This is the best we know right now but it is not as much as we wish we knew. You will have to decide anyhow.”

However, when critically ill patients are being asked to make treatment decisions, they need recommendations based on higher levels of confidence in the medical evidence which applies to them on that day.

This study is an important first step in what surely will be a process of review and revision of the development of cardiac guidelines.

JAMA

Context  “The joint cardiovascular practice guidelines of the American College of Cardiology (ACC) and the American Heart Association (AHA) have become important documents for guiding cardiology practice and establishing benchmarks for quality.

Objective  “To describe the evolution of recommendations in ACC/AHA cardiovascular guidelines and the distribution of recommendations across classes of recommendations and levels of evidence.

Data Sources and Study Selection  “Data from all ACC/AHA practice guidelines issued from 1984 to September 2008 were abstracted by personnel in the ACC Science and Quality Division. Fifty-three guidelines on 22 topics, including a total of 7196 recommendations, were abstracted.(Emphasis added)

Conclusions  “Recommendations issued in current ACC/AHA clinical practice guidelines are largely developed from lower levels of evidence or expert opinion. The proportion of recommendations for which there is no conclusive evidence is also growing. These findings highlight the need to improve the process of writing guidelines and to expand the evidence base from which clinical practice guidelines are derived.” (Emphasis added)

Citation:  JAMA, 2009: 301(8):831-841