Evidence-based Medicine?

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Scientists know a lot about infectious diseases. But a new study in the Archives of Internal Medicine finds that the treatment guidelines created by the Infectious Diseases Society of America (IDSA) are based on imperfect evidence. Only one in seven treatment recommendations relied on evidence from a randomized controlled trial, the gold standard in medicine.

In a randomized trial, participants are randomly assigned to one of two groups—the “treatment” group or the control group. The control group receives the standard of care, say ibuprofen for a headache. The treatment group receives whatever new-fangled drug or intervention the researchers want to test, say meditation or Valium.

At first blush, this apparent lack of high-quality evidence may seem like cause for outrage. But ask any medical researcher, and they will tell you that clinical trials are crazy expensive. In some cases, they aren’t even possible. And in other cases, they’re just plain stupid: We don’t need a clinical trial, the authors point out, to tell us that staying far away from ticks cuts our risk of contracting Lyme disease, nor do we need a clinical trial to tell us that nurses and doctors should wash their hands to prevent the spread of infections.

Still, physicians who follow treatment recommendations no doubt think that they’re practicing evidence-based medicine. And they are, sort of. But often the evidence is pretty weak. The study reports that more than half of IDSA’s treatment recommendations rely heavily on expert opinion or anecdotal evidence. The guidelines for treatment of blastomycosis and sporotrichosis, two fungal infections, were based totally on expert opinions, committee reports, or descriptive studies. Yipes. Not the kind of evidence that inspires confidence.

Like it or not, medicine is still as much of an art as it is a science. Doctors and nurses must take into account not only the treatment guidelines — which may or may not be based on sound science — but also all the factors that make you you — your allergies,  your medical history . . . the list goes on and on. Some day we may have handheld computers that allow physicians to diagnose diseases and cure them in one fell swoop. But that day is a long, long way off.

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Image credit: takacsi75 on flickr

Read the editorial that accompanies this study here (subscription required).

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Categorized in: Cassandra, Health/Medicine

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