Study conclusions were based upon an extensive review of guideline recommendations for heart care, as set out by the American College of Cardiology (ACC) and American Heart Association (AHA).  Pierluigi Tricoci M.D., M.H.S., Ph.D., and colleagues from Duke University examined these recommendations and evaluated the strength of the evidence which underlie them.  The analysis included data from all the ACC/AHA practice guidelines issued over the past 24 years and encompassed 53 guideline documents containing over 7000 recommendations.

What the investigators found was that, on average, only 11% of the recommendations in each current guideline were actually backed by very strong evidence.   Most recommendations were based on less clear research findings or on the consensus opinion of experts.

“Our finding that a large proportion of recommendations in ACC/AHA guidelines are based on lower levels of evidence or expert opinion highlights deficiencies in the sources of definitive data available for the generation of cardiovascular guidelines” state the authors. 

They go on to say “to remedy this problem, the medical research community needs to streamline clinical trials, focus on areas of deficient evidence, and expand funding for clinical research.”

According to the American College of Cardiology, this study should help send “a valuable and important message to the new Administration, Congress and the nation about the need to invest more in science, medical evidence and clinical comparative effectiveness”.  The ACC fully supports the call for increased national funding of medical research.

It is important to understand that the ACC/AHA practice guidelines offer guidance to help healthcare providers determine the best treatment options for their patients.  These guidelines are developed after careful analysis of the strongest scientific evidence available at the time.  In some cases, however, evidence is limited or not available, so some recommendations are based on the consensus agreement of leading experts in heart disease care.

 “Despite limitations of the current evidence base, we can see that guideline-driven care has resulted in real progress in our fight against heart disease,” said Tim Gardner, M.D., president of the American Heart Association.  “However, that fight is far from over.” 

“There are gaps in the evidence base for patient care, gaps that could be eliminated if more clinical research was funded, especially comparative effectiveness research that specifically compares one kind of diagnostic procedure or treatment with another,” said W. Douglas Weaver, M.D., president of the American College of Cardiology.  “Improving our evidence base can lead to even greater improvements in treatment and in saving lives.”

      Gardner and Weaver note that the paper by Tricoci highlights two important issues:

• The recommendations in the guidelines should always be placed in the context of each patient’s unique clinical situation and the patient’s values and wishes.
• Weighing the impact of new data on the existing body of knowledge is not straightforward and often takes time.  Nonetheless, patient care must continue and care decisions need to be made.  The consensus opinion of leading experts can be invaluable under such circumstances, and cannot be minimized.
  

 “The guidelines we have developed to-date are based on the best evidence we have available to us and they are working,” Weaver said. “We will continue to pursue the knowledge needed to maintain and improve our progress in saving lives.”

“Can we do better? Certainly, actually in several ways,” Gardner said.  “We can do a better job of communicating those best practices to providers and ensuring they are used when they are the right treatment for the patient.  And we can continue to advocate for adequate funding and other improvements in our clinical research infrastructure.  We can continue to make an important difference.”