When Evidence and Practice Collide

This section is compiled by Frank M. Painter, D.C.
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FROM:   J Manipulative Physiol Ther 2005 (Oct);   28 (8):   551–553 ~ FULL TEXT

Robert D. Mootz, DC

Office of the Medical Director,
State of Washington Department of Labor and Industries,
P.O. Box 44321
Olympia, Washington 98504-4321, USA

“Until now, we believed that the best way to transmit knowledge from its source to its use in patient care was to first load the knowledge into human minds… and then expect those minds, at great expense, to apply the knowledge to those who need it. However, there are enormous ‘voltage drops’ along this transmission line for medical knowledge.” [1]
~ Lawrence Weed, 1999

It sounds good, doesn't it? Evidence-based practice (EBP)—Sackett has characterized it as the conscientious and judicious use of current best evidence in making decisions about the care of individual patients. [2] Key to his conceptions are that individual clinical expertise, best research evidence, and patient values are all factored into clinical decision making. Bolton has furthered the ideal with her contentions that the evolution of EBP requires maturation of both research and practice methodologies to better address the issue of evidence suitability. [3] Key to her conceptions are that EBP specifically involves matching knowledge gleaned from scientifically derived information to individual patient settings, that is, encouraging individual physicians to explicitly seek out and factor in scientifically gained knowledge into daily clinical decision making. Of course, this entails overcoming the inertia of practicing within the “comfort zones” that we have developed based on our training.

Although resources now abound to assist clinicians in the process of incorporating evidence into practice, the reality of information overload still prevails. As of 2004, the National Library of Medicine added almost 11,000 new articles per week to its databases. [4] Just to stay current in internal medicine, an internist would need to read some 20 articles per day 365 days a year. [5] When I began my career, I can proudly proclaim that I owned every chiropractic textbook published by a mainstream publisher and knew personally every chiropractic researcher in the indexed literature. Fortunately, for the science of chiropractic, that no longer holds true. Thus, “relevance retrievability” from the mass of literature has become acutely critical.

Furthermore, the user-friendly secondary information sources such as evidence summaries and clinical practice guidelines we rely on to offset information overload suffer from every limitation human nature conjures up including error, aging, bias, and misinterpretation. Superimposed on all of the impediments individual physicians must overcome are administrative hassles that spring forth from the business and regulatory constraints of contemporary health care. Dichotomous decisions have to be made about what to pay for with pooled public or private resources, balanced among competing demands of the market place. Fig 1 summarizes evidence ideals and realities faced by both clinicians and policy makers. In fact, it is this policy/practice interface where evidence and practice collide.

The following 3 conceptual strategies illustrate our challenges:

Evidence Appropriatism   This is how EBP was meant to be. Evidence is used by all to better inform the choices patients have in making clinical decisions with their physicians, not to regulate them. End users have an appreciation of the strengths and limitations of varying qualities of evidence. Evidence suitability trumps evidence hierarchies, and the end users have real-time access to high-quality information. Guidelines are living documents refined regularly with new information and experience. Evidence is a tool to improve practice specifically and how we administer health care generally. It also is a tool that may require you to change what you do.

Evidence Nihilism   This represents the perspective that one cannot act until definitive evidence is available. From such a vantage point, the absence of evidence qualifies as evidence against, as does conflicting evidence. Although it sounds extreme, there are situations (such as when making a coverage decision regarding a procedure with high risk of adverse outcome) where more rigorous standards may be appropriate. However, this approach can sometimes be applied in default fashion to the detriment of various clinical situations.

Evidence Agendaism   This strategy reflects the selective use of evidence to bolster one's preconceived notions. For example, a payer might seek out and act on evidence that favors their business need while ignoring that which does not. Capping a chiropractic benefit or restricting coverage for known best practices under the auspices of “following a guideline” comes to mind. It may be a practical business decision to make, but “blaming the evidence” illustrates this strategy. Likewise, providers may promulgate and promote studies that emphasize a miniscule, marginal advantage (eg, a small improvement in pain in the absence of any functional improvement) or benefits out of context. Citing beneficial cost studies that used assumptions of noncoverage in a Canadian province to a US payer that already has a moderately robust chiropractic benefit might be an example. “Agendaism” may be naïve or overt. Of course, when evidence does appropriately challenge one's own preconceived notions, the challenged party might wrongly assume agendaism on the part of the challenger.

The evidentiary contest in which the health care system now finds itself requires all parties to improve their understanding and application of evidence. Adapting behavior to aptly grapple with what evidence tells us is perhaps the highest priority. Clinicians must build time and routine into their workday to consider evidence in individual care decisions, as well as constructively engage administrative efforts to apply evidence to their decision making. Because it is change, it is challenging, but the evolution is straightforward.

Within a clinical setting, becoming a consumer of research information is really as easy as searching a free online database such as PubMed for articles on a couple clinical conditions seen in the past week. Reading through abstracts on recent literature may reveal new best practices or shed light on practices that are not useful. Development of an “evidence culture” will prepare chiropractors for adapting to the changes facing health care. Fig 2 outlines several examples of what practitioners can do, individually and collectively, to increase their comfort level with evidence and, thus, recognize its value and limitations for practice.

To operationalize EBP, it is critical to focus on “patient-oriented evidence that matters.” [6] That simply means that the outcomes one aims to improve are truly relevant to the patient. For example, a clinical finding such as segmental range of motion that is believed by the physician to be useful may be of far less interest to the patient or society at large than a functional performance outcome such as how long they can perform work with out pain. Physiologic measures may be of interest, but the value and tangible benefit to the consumer-patient as well as the customer-payer must be clear.

Evidence-based practice can also help to refine care processes to reduce mistakes. From a quality-improvement perspective, reduction and elimination in defects (misuse, underuse, and overuse) to diminish waste and inefficiency will not only benefit patients, but also will enhance the “competitiveness” of the practitioner in the community. For examples, see the Bridges to Excellence Web site (www.bridgestoexcellence.org/bte/index.html). There is increasing availability of comparative provider performance data now being made available to consumers. This trend will likely increase and is envisioned as a way to contribute to increased accountability as well as quality improvement.

Policy makers must confront the dilemmas that evidence can only inform the adjudication and policy decisions they must undertake. Evidence cannot make decisions for them. Researchers, more than ever before, must recognize that subtleties such as which outcome will become a primary hypothesis or which exclusion criteria are adopted may inadvertently drive a large-scale policy decision that impacts broader coverage.

Evidence-based practice is a contemporary reality impacting clinician, scientist, and policy maker alike. Inherent in all that EBP stands for is bettering patient outcomes and reducing expenditures on ineffective care. Evidence-based practice is still maturing, and infrastructures for supporting and adapting to it are still evolving. With all its inherent challenges, EBP remains the best hope in overcoming Weed's “voltage drops.”


  1. Weed LL, Weed L.
    Opening the black box of clinical judgment—an overview
    BMJ. 1999 (Nov 13); 319 (7220): 1279 ~ FULL TEXT

  2. Sackett DL.
    Evidence-based medicine.
    Spine. 1998;23:1085–1086

  3. Bolton JE.
    The evidence in evidence-based practice: what counts and what doesn't count?
    J Manipulative Physiol Ther. 2001 (Jun); 24 (5): 362-6 ~ FULL TEXT

  4. US National Library of Medicine . Fact sheet.
    Bethesda (Md): US National Library of Medicine; 2005; Apr 7 [cited 2005 Jul 1].
    Available from http://www.nlm.nih.gov/pubs/factsheets/nlm.html

  5. Shaneyfelt TM.
    Building bridges to quality.
    JAMA. 2001;286:2600–2601

  6. Ebell MH, Barry HC, Slawson DC, Shaughnessy AF.
    Finding POEMs in the medical literature.
    J Fam Pract. 1999 (May); 48 (5): 350-5


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