Surprise! There May Not Be As Much Science Behind Medical Therapies As You Might Think.
Surprise! There May Not Be As Much Science Behind Medical Therapies As You Might Think.According to an article in The Wall Street Journal, by Ron Winlow, on February 25, 2009, even though heart disease is among the most studied illnesses in all of medicine, just 11% of more than 2,700 recommendations approved by cardiologists for treating heart patients are supported by high-quality scientific testing, according to new research.
About half the medical recommendations for heart patients have limited scientific backing, according to a study published in Wednesday's Journal of the American Medical Association. Instead, they are based mostly on expert opinion -- subjective viewpoints where consensus is often lacking.
For instance, people who previously have had a heart attack and take an aspirin daily to help avert a second such incident can rest assured that the treatment is supported by rigorous scientific studies. But there is much less certainty around another common recommendation that patients treated with artery-opening stents remain on a potent blood thinner for a year to avoid a rare but potentially life-threatening blood clot. The downside: Patients who stay on blood thinners for an extended time risk potential complications if they need urgent surgery.
The findings from the JAMA study reflect the challenge doctors and patients face in choosing the best course of treatment for a variety of conditions. And they underscore that even though drug and device companies, government agencies and philanthropic groups have spent billions of dollars developing and testing new treatments in recent years, much of what happens in the doctor's office or the hospital operating suite might not be based on rigorous scientific evidence.
"In most situations that we encounter when we see patients, it isn't so clear what is the best thing to do," says Pierluigi Tricoci, a cardiologist at Duke University's Duke Clinical Research Institute and lead author of the study.
For more than two decades, health-policy experts, health insurers and employers have been beating the drum for evidence about what works and what doesn't in medicine in an effort to reduce wide variation in medical care, cut health-care costs and develop standards by which to measure the performance of doctors, hospitals and health plans.
This month, the Obama administration and Congress budgeted more than $1 billion of the economic stimulus package to fund research for comparing the effectiveness of different treatments in head-to-head studies aimed at providing evidence to clinicians and insurers on the best treatment strategies.
"We need those studies to make the kind of changes in health care that are being talked about -- being sure we get the best possible care for our patients in the most cost-effective manner," says Sidney Smith, a medical guidelines expert and cardiologist at University of North Carolina, Chapel Hill and senior author of the JAMA paper.
The American College of Cardiology and the American Heart Association have been jointly issuing guidelines to doctors on care of cardiovascular patients for more than 20 years. Recommendations based on multiple randomized clinical trials, in which patients are randomly assigned a treatment, are considered having the highest level of evidence. A single randomized study or non-randomized studies comprise the second level, while recommendations backed by expert opinion or case studies are considered having the weakest evidence. Guidelines are also ranked by whether empirical evidence or general opinion supports that a treatment is useful and effective or not.
For instance, strong evidence of benefit based on several randomized controlled clinical studies is behind guidelines calling for use of aspirin, cholesterol medications called statins and other pills called beta blockers among heart patients to avoid a second heart attack. Similar rigor is behind recommendations that patients who arrive at the emergency room with a major heart attack get treated with an angioplasty balloon within 90 minutes.
Experts Disagree. But such examples are the exception. For a variety of other conditions, treatment recommendations rely largely on non-randomized studies or expert opinion. For instance, it's unclear at what point patients who suffer excess bleeding during a heart procedure should get a blood transfusion, Dr. Tricoci says. And debate rages among cardiologists over two new tools for assessing a patient's long-term risk of a heart attack. When does a blood test for a marker called C-reactive protein aid in making such a prediction? How about a scan to check for calcium buildup in a patient's arteries? Mounting evidence supports each test, but more data are needed to determine how they might best be used, Dr. Tricoci says.
Harlan Krumholz, a cardiologist at Yale University School of Medicine, says doctors should disclose to patients the strength of the evidence behind the care they recommend. "Treatment decisions are often made very dogmatically even when the level of evidence isn't very strong," he says.
One reason for the lack of stronger evidence is that the large "megatrials" that have dominated cardiovascular research in the past decade were sponsored by drug and device companies. While those studies provide an important source of information, they are typically designed primarily to win approval for a treatment or to widen the market for a therapy already on the market, and not to guide treatment decisions, according to the JAMA study.
Limitations of Studies. Clinical studies also typically exclude patients with complicated illness, which can limit the ability of doctors to apply findings to many of their patients. For instance, many heart patients also suffer from kidney disease. But contrast agents typically given to patients undergoing a diagnostic X-ray called cardiac catheterization can be harmful to kidneys.
Dr. Tricoci says he and his colleagues also observed that guideline writers are picked for their expertise in the field -- but they are also often those who consult regularly with industry. Such possible conflict of interest raises the potential to introduce bias into the guidelines, undermining their credibility.
Dow Jones & Company, Inc. 2008