Using Concepts From Evidence Based Medicine to Find the Best Evidence

Evidence based medicine has been defined as “the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.” Individual clinical expertise should be combined with the best available external clinical evidence (i.e., clinically relevant, patient-centered research).¹

Finding the best available evidence requires formulating the question, systematically searching a variety of sources of information, and critically appraising the information gathered.² In orthotics and prosthetics, the question will commonly focus on the effectiveness of an intervention. The type of patient, the clinical intervention (and a comparison intervention, if relevant), and the clinical outcome(s) of interest should all be specified in the question.^{2, 3}

The quest to find the best available evidence should include a search of bibliographic databases (such as MEDLINE and RECAL), a review of reference lists from related articles, and an attempt to obtain unpublished data from researchers or research sponsors.^{2, 4} The focus of the database search should be on articles published in peer-reviewed journals.⁵ However, the searcher should be aware that bibliographic databases do not index all journals and that it may be difficult to find relevant articles due to the methods used to index the articles and the searcher’s inexperience using the database.⁴ The searcher should also be aware that published evidence may be incomplete. Some research does not get submitted for publication; the researcher may fail to write the paper or the sponsor may not want the results published. In addition, positive results are more likely to be published than negative results.⁴

The Internet contains a wide range of easily accessible information. However, it is difficult to efficiently identify valid information since Web pages are not routinely reviewed for content and accuracy. The credibility of the source (including author credentials, the site sponsor, the date the site was updated, and possible conflicts of interest) should be determined before using the information.⁶

Critical appraisal of the evidence centers on determining the validity (i.e., are the results likely to be true) and clinical usefulness of the information.² For a question about the benefits of a particular treatment or intervention, data from properly conducted randomized controlled trials are preferred (although a randomized trial may not be practical or suitable for every question). The process of randomization, if used, eliminates many of the biases that may lead to false results in a non-randomized trial.⁷ Other study designs, including cohort studies, case-control studies, case series, and case reports, may be appropriate based on the question, but the reader should be aware of the strengths and limitations of these study types. Non-systematic reviews are typically easy to read but they may be misleading if key studies are omitted from the review or if data from individual articles is selectively reported. A systematic review of multiple welldesigned randomized trials is considered by many to be the strongest study design.⁴ A systematic review involves a clearly defined, comprehensive search for published and unpublished data and an assessment of the quality of the papers included in the review. Data from multiple sources may be pooled and re-analyzed using a technique called meta-analysis.⁴

Several authors have proposed series of questions that can be used in appraising studies of different design types.^{2, 4, 5, 7, 8} Typical questions for a clinician to ask when reviewing a randomized trial about treatment include:

1. Was the assignment of patients to treatments truly randomized?

2. Were all patients who entered the study accounted for at its conclusion?

3. Were patients and study personnel blinded to the treatment?

4. Were the patient groups similar at the start of the study?

5. Were the groups treated equally with the exception of the experimental intervention?

6. Were both statistical and clinical significance considered?

7. Were all clinically relevant outcomes reported?

8. Is the intervention feasible in my practice?

9. Were the study patients recognizable (i.e., was enough information given about the patients included in the study) and similar to the patients in my practice?

10. Are the likely benefits worth the potential harms?

Concepts from evidence based medicine, specifically formulating a concise question, searching all available sources for both published and unpublished data, and appraising the evidence can assist the orthotist or prosthetist in finding the best available evidence pertaining to a specific topic. With the rapid growth in available information both in print and on the Internet, clinicians need to focus on the best evidence to assist in making decisions about optimal treatments for their patients.

References

1. Sackett DL, Rosenberg WMC, Muir Gray JA, Haynes RB, Richardson WS. Evidence-based medicine: what it is and what it isn’t. British Medical Journal 1996;312:71-2.

2. Rosenberg W, Donald A. Evidence based medicine: an approach to clinical problemsolving. British Medical Journal 1995;310:1122-6.

3. Otto J. Assessing the relevance & value of clinical research studies. O & P Business News 2001;10:8:26-35.

4. Muir Gray JA. Evidence-based healthcare. New York: Churchill Livingstone, 1997.

5. Miser WF. Critical appraisal of the literature: how to assess and article and still enjoy life. In Geyman JP, Deyo RA, Ramsey SD (eds.) Evidence-based clinical practice: concepts and approaches. Boston: Butterworth Heinemann, 2000:41-56.

6. Davoren JB. Searching the Internet. In Friedland DJ (ed.) Evidence-based medicine – a framework for clinical practice. Stamford, CT: Appleton & Lange, 1998:139-44.

7. Department of Clinical Epidemiology and Biostatistics, McMaster University Health Sciences Centre. How to read clinical journals: V: To distinguish useful from useless or even harmful therapy. Canadian Medical Association Journal 1981;124:1156-62.

8. Greenhalgh T. How to read a paper – the basics of evidence based medicine. London: BMJ Publishing Group, 1997.