Who Says What's Best?

Evidence-based medicine has the ring of scientific authority. But it's not as self-evident as it sounds. EBM is a movement born in the 1990s as an alternative way of practicing medicine, in which "best" evidence, gleaned mostly from randomized clinical trials and cost-benefit studies, is the basis for what docs should or shouldn't do. Touted as a way to improve patient care and restrain unnecessary treatment, EBM sees itself as a major shift away from traditional medicine that emphasizes the expertise of the medical profession. That includes knowledge of the underlying nature of disease, mechanisms of therapy, basic and clinical research, and physician experience. The autonomy and authority of the doctor, and the subsequent variability in care, are the problems that EBM wants to cure.

It's no surprise that EBM draws strong support from governments that seek uniform standards to assess performance and cost effectiveness. According to Marc Rodwin, professor of law at Suffolk University Law School in Boston, EBM puts experts trained in social science, public health, epidemiology, and economic analysis on par with physicians and "breaks the lock hold" the profession has over how medicine is practiced and compensated. Depending on where you sit, that may be good or bad. But you still have to recognize that EBM carries its own ideological and political agenda separate from its clinical purpose.

Remember the mammogram wars over whether women should get them during their 40s? The protagonists were the EBM-ers who said no and the radiologists and oncologists who said yes. For the naysayers, randomized clinical trials were inadequate to show that the test saved lives, even though it did detect cancers sooner. Such a mammogram program would be costly, and unnecessary biopsies for false positive readings even costlier. But based on their interpretation of clinical evidence, cancer experts maintained that the test saved lives. What's more, they factored in the nature of the disease: more aggressive in younger women and best cured if picked up early. But in 1997 the Department of Health and Human Services gave a thumbs down to recommending that women start having mammograms in their 40s. Women promptly exercised their political clout, which led to an HHS reversal. (In fact, the trend has been for more screening in this age group, not less.)

EBM also questions the prostate-specific antigen test, or PSA, for prostate cancer. The evidence-based method concludes that the test brings more harm than benefit, as it leads to unneeded biopsies and surgeries on often slow-growing cancers. This is at odds with the American Cancer Society, which says that men should have annual PSAs starting at age 50, and African-Americans, who have a higher prostate cancer rate, at age 45. This does not help that young primary-care doctor who published a mournful essay in the Journal of the American Medical Association in 2004. He did not get a PSA on his 53-year-old patient, based on his dutiful practice of evidence-based medicine. When found to have advanced prostate cancer, the patient sued and won. The jury put its faith in the medical experts who testified that PSAs are the best way to pick up tumors when they are most treatable.

Sift and sliver. Were these tests not so well known, the selective rules of evidence-based medicine might have prevailed. Patients would have been none the wiser. This concern underlies a scathing commentary on the EBM movement in the International Journal of Evidence-Based Healthcare by Dave Holmes, a professor of nursing at the University of Ottawa. He and his colleagues argue that EBM is "outrageously exclusionary" and even "microfascism" in the way it sifts knowledge. Though harsh, he makes a point: By anointing only a small sliver of research as best evidence and discarding or devaluing physician judgment and more than 90 percent of the medical literature, patients are forced into a one-size-fits-all straitjacket. Ironically, this comes at a time when both human genomics and informed patients are demanding more tailored and personal prescriptions for care.

EBM has its merits, but let's make it just what it claims to be: a system to gather and synthesize evidence and disseminate it widely in order to enhance medical decision making. Do so using the full range of relevant medical knowledge and science and the foremost thinking of its experts, without political or ideological bias. This "best" EBM should be integrated into medicine, not be at odds with it.