Editor's Note: The following is an excerpt from the new book Demand Better! Revive Our Broken Health Care System (Second River Healthcare Press, March 2011) by Sanjaya Kumar, chief medical officer at Quantros, and David B. Nash, dean of the Jefferson School of Population Health at Thomas Jefferson University. In the following chapter they explore the striking dearth of data and persistent uncertainty that clinicians often face when having to make decisions.
Myth: There is a high degree of scientific certainty in modern medicine
"In America, there is no guarantee that any individual will receive high-quality care for any particular health problem. The healthcare industry is plagued with overutilization of services, underutilization of services and errors in healthcare practice." – Elizabeth A. McGlynn, PhD, Rand Corporation researcher, and colleagues. (Elizabeth A. McGlynn, PhD; Steven M. Asch, MD, MPH; et al. "The Quality of Healthcare Delivered to Adults in the United States," New England Journal of Medicine 2003;348:2635-2645.)
Most of us are confident that the quality of our healthcare is the finest, the most technologically sophisticated and the most scientifically advanced in the world. And for good reason—thousands of clinical research studies are published every year that indicate such findings. Hospitals advertise the latest, most dazzling techniques to peer into the human body and perform amazing lifesaving surgeries with the aid of high-tech devices. There is no question that modern medical practices are remarkable, often effective and occasionally miraculous.
But there is a wrinkle in our confidence. We believe that the vast majority of what physicians do is backed by solid science. Their diagnostic and treatment decisions must reflect the latest and best research. Their clinical judgment must certainly be well beyond any reasonable doubt. To seriously question these assumptions would seem jaundiced and cynical.
But we must question them because these beliefs are based more on faith than on facts for at least three reasons, each of which we will explore in detail in this section. Only a fraction of what physicians do is based on solid evidence from Grade-A randomized, controlled trials; the rest is based instead on weak or no evidence and on subjective judgment. When scientific consensus exists on which clinical practices work effectively, physicians only sporadically follow that evidence correctly.
Medical decision-making itself is fraught with inherent subjectivity, some of it necessary and beneficial to patients, and some of it flawed and potentially dangerous. For these reasons, millions of Americans receive medications and treatments that have no proven clinical benefit, and millions fail to get care that is proven to be effective. Quality and safety suffer, and waste flourishes.
We know, for example, that when a patient goes to his primary-care physician with a very common problem like lower back pain, the physician will deliver the right treatment with real clinical benefit about half of the time. Patients with the same health problem who go to different physicians will get wildly different treatments. Those physicians can't all be right.
Having limited clinical evidence for their decision-making is not the only gap in physicians' scientific certainty. Physician judgment—the "art" of medicine—inevitably comes into play, for better or for worse. Even physicians with the most advanced technical skills sometimes fail to achieve the highest quality outcomes for their patients. That's when resourcefulness—trying different and potentially better interventions—can bend the quality curve even further.
And, even the most experienced physicians make errors in diagnosing patients because of cognitive biases inherent to human thinking processes. These subjective, "nonscientific" features of physician judgment work in parallel with the relative scarcity of strong scientific backing when physicians make decisions about how to care for their patients.
We could accurately say, "Half of what physicians do is wrong," or "Less than 20 percent of what physicians do has solid research to support it." Although these claims sound absurd, they are solidly supported by research that is largely agreed upon by experts. Yet these claims are rarely discussed publicly. It would be political suicide for our public leaders to admit these truths and risk being branded as reactionary or radical. Most Americans wouldn't believe them anyway. Dozens of stakeholders are continuously jockeying to promote their vested interests, making it difficult for anyone to summarize a complex and nuanced body of research in a way that cuts through the partisan fog and satisfies everyone's agendas. That, too, is part of the problem.
Questioning the unquestionable
The problem is that physicians don't know what they're doing. That is how David Eddy, MD, PhD, a healthcare economist and senior advisor for health policy and management for Kaiser Permanente, put the problem in a Business Week cover story about how much of healthcare delivery is not based on science. Plenty of proof backs up Eddy's glib-sounding remark.
The plain fact is that many clinical decisions made by physicians appear to be arbitrary, uncertain and variable. Reams of research point to the same finding: physicians looking at the same thing will disagree with each other, or even with themselves, from 10 percent to 50 percent of the time during virtually every aspect of the medical-care process—from taking a medical history to doing a physical examination, reading a laboratory test, performing a pathological diagnosis and recommending a treatment. Physician judgment is highly variable.
Here is what Eddy has found in his research. Give a group of cardiologists high-quality coronary angiograms (a type of radiograph or x-ray) of typical patients and they will disagree about the diagnosis for about half of the patients. They will disagree with themselves on two successive readings of the same angiograms up to one-third of the time. Ask a group of experts to estimate the effect of colon-cancer screening on colon-cancer mortality and answers will range from five percent to 95 percent.
Ask fifty cardiovascular surgeons to estimate the probabilities of various risks associated with xenografts (animal-tissue transplant) versus mechanical heart valves and you'll get answers to the same question ranging from zero percent to about 50 percent. (Ask about the 10-year probability of valve failure with xenografts and you'll get a range of three percent to 95 percent.)
Give surgeons a written description of a surgical problem, and half of the group will recommend surgery, while the other half will not. Survey them again two years later and as many as 40 percent of the same surgeons will disagree with their previous opinions and change their recommendations. Research studies back up all of these findings, according to Eddy.