Everything You Always Wanted to Know About EBM (But Were Afraid to Ask)


While it has become fashionable among pundits to speak of the trend toward evidence- based medicine (EBM) in modern healthcare practice as something of a paradigm shift, new and revolutionary, this...

Everybody’s Doing It

While it has become fashionable among pundits to speak of the trend toward evidence- based medicine (EBM) in modern healthcare practice as something of a paradigm shift, new and revolutionary, this way of framing the story is also misleading, suggesting as it does that physicians of the past relied on something other than evidence—tea leaves, perhaps, or voices in their heads—to guide their decisions. The truth is that evidence, whether obtained from a peer-reviewed study or from one’s own eyes, has been inextricably intertwined in the practice of every responsible physician since medicine was born, and it will continue to be for as long as medicine is practiced. In this sense, at least, nothing has changed.

What has changed, rather dramatically, is the technology by which evidence may be gathered, shared, and accessed. Twenty-five—or even 10—years ago, a doctor who wished to supplement his or her clinical experience with research data had a relatively limited set of options. A trip to the nearest medical library might turn up a few relevant studies, but limited time and limited media—remember microfiche?—made a comprehensive survey of all the available data too time-consuming to be of use in a time-sensitive clinical situation. Furthermore, even the simplest kind of research—essentially flipping through back issues of JAMA or other journals—was impossible to perform in an office setting; physicians called upon to make on-the-spot decisions, diagnoses, and recommendations were forced to rely on their own memories and hope they’d seen the right study.

Then came computers, which made evidence easier to store in large quantities. Then the Internet, which made evidence easier to share, and the advent of wireless technology and the PDA, which made it portable. Modern technology has made it possible for physicians to use evidence more effectively, and to access a great deal more of it, than ever before. As Daniel Friedland, MD, author of Evidence-Based Medicine: A Framework for Clinical Practice, notes, the phrase “evidence-based medicine” in the sense it is meant today represents not a paradigm shift but an “evolution of the tools used to practice scientific medicine.”

It is for this reason that EBM, at least in theory, has become widely (almost universally) accepted in the year or so since our last article on the subject, in September of 2003. While a true paradigm change might be expected to engender a great deal of resistance, the blossoming of the technology needed to support the existing paradigm can only be a welcome development. EBM in the modern sense, defined in our previous article as “the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of the individual patient,”can no longer be clearly distinguished from medicine in general. “It’s no longer cutting edge; it’s mainstream,” says Dr. Friedland. “It’s interwoven in the fabric of what physicians do.”

More guidelines than ever before—and all guidelines sponsored by federal or other government institutions—are formulated on the basis of evidence. The American Academy of Family Physicians has published rigorous guidelines mandating that evidence-based medicine be incorporated into every CME activity sponsored by the organization. EBM is a required part of the curriculum at all but a tiny handful of US medical schools. When he was asked to give a presentation at a meeting of the Michigan Academy of Family Practice on the subject of EBM, says Dr. Friedland, “I had to fill out forms to certify that my evidence- based medicine presentation was evidence-based!”

The increased emphasis on EBM is slowly changing the way that physicians and patients think about and participate in medical practice. In a series of online slides, British Medical Journal editor Richard Smith identifies some important changes wrought by EBM; these include:

• An increased ability to quantify and evaluate the clinical skills of a physician, which were once seen as “semimystical.”

• To practice the best medicine possible, physicians must constantly access different sources of information, rather than relying only on their own accumulated knowledge.

• Patients are more often encouraged to participate in clinical trials in order to ensure a continuous stream of new and up-to-date evidence.

• Patients are more often encouraged to be active partners in their own care, rather than passive “pupils.”

• A patient now has ready access to most of the same sources of information as his or her doctor.

As these changes, and most of the others described by Smith in his presentation, are largely positive for the healthcare system as a whole, most physicians have embraced EBM as a concept. The challenge in the years to come lies in getting the concept operationalized— that is, in getting individual physicians to actually incorporate evidence into their day-to-day practice. Even doctors who are wholeheartedly enthusiastic about the idea may be unfamiliar with the skills they’ll need to learn and technologies they’ll need to master in order to make EBM a practical reality.

And that, of course, is our cue. For the remainder of this article, we will assume that you are already sold on EBM as a concept and would like to implement it to one degree or another in your own practice; this article is designed to show you how to accomplish this (if you need further convincing on the merits of EBM, read our earlier article or any of the dozens of pro-EBM texts to which that article links).

Finding Balance

So! You are a modern, open-minded medical practitioner, an MD Net Guide reader and thus at least somewhat tech-savvy, and are eager to back your clinical decisions with evidence, starting today.

First you’ll need to ask yourself a few key questions about your goals and resources, as well as about the specific needs and characteristics of your particular practice. In order to be sure that you’re asking the right questions, it will be helpful to pursue a brief technical digression concerning the nature of “evidence.” In a 2001 article published in Evidence-Based Medicine, R. Brian Haynes, presently the Chair of the Department of Medicine at McMaster University, proposed a four-tiered hierarchical method of categorizing all evidence. Broadly speaking, says Haynes, all evidence can be arranged on a four-level pyramid; the base of this pyramid comprises all of the individual studies whose results are available for viewing. Single studies form the foundation of EBM, providing the raw data by which clinical decisions may be guided. However, because each study addresses only a specific population, and generally has a narrow area of focus, getting a complete answer to a given clinical question by combing through dozens of related studies may be too time-consuming to be worthwhile.

At this point, the physician would move one step up Haynes’ pyramid, where syntheses that digest and summarize data from multiple studies are located; these might include reviews (eg, the Cochrane Collection), meta-analyses, or clinical guidelines incorporating clinical trial results. The third tier of the pyramid contains synopses, such as JournalWatch or InfoPOEMS, in which EBM experts review and critique available data and place it in context based on knowledge from other sources. At the top of the Haynes pyramid is the system, the panacea toward which EBM as a practice aspires. In a system, evidence is driven in easily usable form directly to the site of the patient encounter, where it is most useful, using a wireless device like a PDA or Tablet PC. Ultimately, the ideal system will incorporate the provision of clinical evidence into an electronic medical record (EMR), automating and increasing the efficiency of the patient encounter. A truly integrated application, which enables the physician to read, for example, Cochrane Reviews, or trial results, at the bedside, write electronic prescriptions, check drug interactions, and embed all of it directly into the patient’s EMR, would make using evidence on a daily basis a much easier proposition. As Dr. Friedland states, “unless guidelines [and other evidence] are available in the doctor’s workflow, the doctor won’t use those guidelines.”

This pyramid becomes useful as the physician attempts to identify ideal sources of information for an evidence-based practice. Dr. Friedland cites a principle, attributed to the good folks at InfoRetriever, which says that the value of any piece of information can be calculated by multiplying the data’s relevance by its reliability, and then dividing by the effort expended to find it. Generally, as one moves up the Haynes pyramid, information becomes: (1) easier and quicker to find; and (2) further removed from the source data. Accordingly, it would seem that the information most valuable to the clinician would come from higher levels of the Haynes pyramid. However, because these higher tiers are further removed from raw data, some physicians may feel that they are less reliable; for this reason, the higher one goes on the pyramid for one’s evidence, the more important it becomes to ensure that each source of information is transparent enough that original data can be found if needed.

When seeking to make EBM a more significant part of your practice, your first step should be to familiarize yourself with the concepts behind the Haynes pyramid. Depending upon your own preferences and the specific clinical questions you’re likely to face, you may wish to start your searches at any of the four levels described above. Says Dr. Friedland, “You can always go to PubMed for information—it’s a very important and reliable database—but you should expect to spend [at least] 20-30 minutes devising an effective search strategy and reading all the information.” A Cochrane review or InfoPOEM might take only a minute to find and a minute to read. A well-executed system will put information instantly into your hands at the bedside in the form of an evidence-based recommendation (along with raw data, billing codes, and the like).

On the other hand, says Dr. Friedland, “I can use my own judgment to evaluate studies and synthesis. By the time I reach the synopsis level, I no longer have direct access to the original data, so I have to have a bit of faith.” Systems ultimately require still more faith in this way, he continues. “If you have a system that just spits out a recommendation, you may wonder why you should believe it. Computers have a way of making lousy data look good by displaying the lousy data on a technological interface.” An EBM system, Dr. Friedland maintains, can be an extremely powerful tool if the physician who uses it is confident in its reliability (again, the aforementioned transparency is important here). Furthermore, some tiers of the Haynes pyramid are flatly ineffective in answering some clinical questions. For example, if you are seeking information on a relatively new drug, on which relatively few studies have been performed, it is likely that few if any synopses or syntheses will be available on the subject; in this case, a simple PubMed search is probably your best option.

So, your first and most important question: how deeply do you wish to plunge into the EBM sea of information? How high up the Haynes pyramid are you interested in going on a daily basis? How much capital are you willing to invest in hardware and information services? Your answers to these questions will determine what parts of the information to follow will be of use to you.

Gearing Up

We’ll begin with a brief discussion of the hardware and software you’ll need to begin your EBM efforts. Certainly, any physician who doesn’t already have a computer in his or her office should purchase one post-haste. A high-speed Internet connection—whether cable modem, DSL, or some other option—is also a prerequisite. Read a brief tutorial on high-speed; for more in-depth information, follow the links from that story, or visit Speed Guide, Broadband Week, or the always reliable CNET.com.

A desktop computer and appropriately peppy broadband Internet connection can get you access to all the data you could ever need, but bringing your computer (and thus, your data) from exam room to exam room is not really an option. For this reason, to all of our readers who have not already done so: hie thee at once to thy nearest technology store or website and purchase a PDA or Tablet PC with wireless Internet connectivity. This will afford you instant access to whatever evidence is available, from any location, at any time. Choosing a PDA is a subject well beyond the purview of this article; there are dozens of models and options, all with characteristic benefits and disadvantages. CNET.com is a reliable source of product reviews on this subject; Dr. Friedland cites The Ectopic Brain as one source of physician-focused handheld product news and reviews. If all else fails, watch the “PDA Resources” and “Technology 101” sections that appear in every issue of this publication for hardware profiles and software recommendations relevant to the EBM- minded physician.

Dr. Friedland also recommends a reliable online medical textbook to any physician interested in practicing evidence-based medicine. For the purposes of EBM—which demands up-to-date information whenever possible—Internet-based textbooks are far superior to their print counterparts. “By the time a paper text appears in print,” says Dr. Friedland, “it may already be a year or even two years out of date.” Online texts can update much more frequently and are consequently a much more reliable resource (not to mention a better long-term investment). A partial listing of some popular available online medical textbooks may be found below.

Finally, the clinician will have to decide whether he or she wishes to incorporate electronic medical recordkeeping into his or her practice. A truly integrated system, in which patient- specific information and tools are on hand at the point-of-care, is not possible in the absence of EMR. Moreover, most experts agree that some form of electronic record will be de rigueur—perhaps even mandatory—in a relatively short period of time; physicians who institute EMR now will get a head start, and save themselves a headache down the line. However, unlike the fairly simple technologies described so far in this section, effecting a transition from paper to electronic recordkeeping represents an enormous investment of time and money, to the tune of several months of diminished productivity and tens of thousands of dollars. Only the individual physician can decide whether this investment is worth the potential reward associated with it. If you do decide to invest in EMR, we strongly suggest reading our July 2004 issue from cover to cover; the two discussions of EMR selection contained therein serve as excellent companions to this article. The American Academy of Family Physicians is also a superb source of information on this subject.

Remember: if you are interested in practicing EBM, it is important that the EMR you select be able to perform as many different functions as possible. For example, if you conduct an evidence-based drug interaction check using your newly instituted system, your EMR service should ideally be able to automatically check the patient’s record and identify potential problems at the point-of-care. More generally, decide in advance what you will want to do, then choose technology that will allow you to do it.

Finding the Evidence

Well, here we are on page six of our EBM survival guide, and we have yet to address the single most important element of practicing evidence-based medicine: identifying good sources of evidence. On our site, we’ll briefly profile some of the most important and reliable EBM resources and databases currently available. We’ll conduct our overview in the same way that the EBM-savvy physician should conduct his or her search for information, working our way down the Haynes pyramid, beginning with EBM systems and moving on to more specific sources of data as necessary.

Want to read the rest of this article?

You’ll have to do it at www.mdng.com

There you’ll find more information on the specific tools and strategies you’ll need to make EBM a reality in your practice.

Online Medical Textbooks

Below, you’ll find an abbreviated listing of some of the more reliable online medical textbooks available to physicians wishing to begin incorporating evidence into their practice on a more regular basis. This list is by no means complete. Notably, it focuses mainly on general medical texts; specialists seeking specialty-specific information will need more specific texts.

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