Why Users' Guides?

Gordon Guyatt, Drummond Rennie, and the Evidence Based Medicine Working Group; EBM Working Paper Series

Past
Present
Future
References

Past

Medical practice is constantly changing. The rate of change is accelerating, and physicians can be forgiven if they often find it dizzying. How can physicians learn about new information and innovations, and decide how (if at all) they should modify their practice?

Possible sources include summaries from the medical literature (review articles, practice guidelines, consensus statements, editorials and summary articles in "throwaway" journals), consultation with colleagues who have special expertise, lectures, seminars, advertisements in medical journals, conversations with representatives from pharmaceutical companies, and original articles in journals and journal supplements. Each of these sources of information might be valuable, though each is subject to its own particular biases [1] [2]. Problems arise when, as is often the case, different sources give different suggestions about patient care.

Without a way of critically appraising the information they receive, clinicians are relatively helpless in deciding what new information to incorporate into their practice. They may choose to believe the most authoritative expert or the trusted colleague, but such reliance forfeits independent judgement. To address this problem, in 1981 the Department of Clinical Epidemiology and Biostatistics at McMaster University published a series of "readers' guides" for clinicians to use when reading clinical articles about the diagnosis, prognosis, etiology, and therapy of their patients' illnesses [3]. The series became one of the most commonly requested set of reprints in the history of the host journal and has been reprinted in seven foreign languages. It is heavily cited in the clinical literature, has been modified for use by the general public, and has appeared in two editions of a text in clinical epidemiology [4]. It was tempting to conclude that clinicians were eager for tools which would allow them to make their own assessments of the original literature.

Present

Experience over the subsequent decade has taught us that, although the Guides are still scientifically sound and clinically useful, they may not meet the immediate needs of busy clinicians, and they can be improved. A group of old and new users, including clinicians at McMaster and colleagues across North America, have been working together to create a new set of guides, published in the Journal of the American Medical Association (JAMA). The new Guides have been inspired by the need for an even more intense focus on using the medical literature to solve real patient problems. This reflects an approach to medical practice which has been called "evidence-based medicine" and involves an ability to access the validity and importance of evidence before applying it to day-to-day clinical problems [5]. The "Reader's Guides" have therefore been transformed into a set of "Users' Guides".

What differences can readers who are familiar with the previous guides expect to find in the new series? As before, the guides aim to assist clinicians' reading in order to keep up to date in their clinical discipline and to find the best way to manage a particular clinical problem. Greater emphasis, however, is given to the latter type of reading and the skills that are required to find information when it is needed. Before one can decide whether to believe an article, one first has to find it. The Users' Guide series introduces strategies for efficiently searching the medical literature.

Once the clinician identifies the relevant studies, she must not only decide whether to believe the information, but also apply it accurately and efficiently to patient care. This involves understanding the magnitude of the impact of a treatment, or the relative usefulness of different diagnostic tests. The new series therefore includes expanded sections on interpreting results of clinical studies, and on deciding how to apply them in patient care. The Users' Guides have also rejected the criterion for reading an article from the Readers' Guides based on the authors' track record since we do not wish to encourage reliance on authority.

Another change follows from the ongoing revolution in the application of scientific approaches to summarizing information from medical research. JAMA has been among the leaders in recognizing the importance of quantitative overviews in providing bottom-line messages that are both clinically applicable and scientifically valid [6] [7]. Clinicians need help in fully understanding these new methods, in differentiating a good overview from a poor one, and in applying their results. The User's Guides puts much greater emphasis on integrative studies, including systematic overviews, practice guidelines, decision analysis, and economic analysis, than did the Readers' Guides. Indeed, we now recommend that resolving a clinical problem begins with a search for a valid overview or practice guideline as the most efficient method of deciding on the best patient care.

Future

We believe that optimal patient care in the 1990s requires an ability to use the medical literature to solve clinical problems.

What impact might the Users' Guides have on physicians who read them carefully, and bring their messages back to their clinical practice?

Clinicians may find themselves relying less on sources of information like "throwaway" journals, pharmaceutical detailing personnel, symposia, and medical advertising.
They may restrict their browsing of the medical literature to summaries, such as the ACP Journal Club, which include only methodologically strong articles [8].
They may address clinical dilemmas more often through a careful definition of the problem, an efficient literature search, and a brief and efficient screening of the articles for the most relevant and valid information.
They are likely to find themselves being more quantitative in their clinical thinking, addressing issues such as "how big an effect can I expect from my treatment in this patient" or "how much does the probability of disease increase as a result of this diagnostic test result".
They will find themselves more clearly differentiating between clinical practices based on sound evidence from studies in human beings and those that are based on physiological rationale or standard practice.
Perhaps most important, they may expect a sense of empowerment when faced with enthusiastic reports of a new technique or approach to care, or with the conflicting recommendations of experts or expert panels [9].

A lot to ask from a series of articles on using the medical literature? Perhaps, but we are confident that the Users' Guides will meet the expectations of clinicians who want to base their clinical decisions more on evidence than hope or authority.

References

1. Rennie D, Bero LA. Throw it away, Sam. The controlled circulation journals. CBE Views. 1990;13:31-5. AJR Am J Roentgenol. 1990 Oct;155(4):889-92.

2. Bero LA, Galbraith A, Rennie D. The publication of sponsored symposiums in medical journals. N Engl J Med. 1992 Oct 15;327(16):1135-40.

3. Department of Clinical Epidemiology and Biostatistics. How to read clinical journals: I. why to read them and how to start reading them critically. Can Med Assoc J. 1981 Mar 1;124(5):555-8.

4. Sackett DL, Haynes RB, Guyatt GH, Tugwell P. Clinical Epidemiology, a Basic Science for Clinical Medicine. 2nd ed. Boston, Little Brown & Co Inc; 1991.

5. Evidence-Based Medicine Working Group. Evidence-based medicine. A new approach to teaching the practice of medicine. JAMA. 1992 Nov 4;268(17):2420-5.

6. Antman EM, Lau J, Kupelnick B, Mosteller F, Chalmers TC. A comparison of results of meta-analyses of randomized control trials and recommendations of clinical experts. Treatments for myocardial infarction. JAMA. 1992 Jul 8;268(2):240-8.

7. Cook DJ, Guyatt GH, Ryan G, Clifton J, Buckingham L, Willan A, McIlroy W, Oxman AD. Should unpublished data be included in meta-analyses? Current convictions and controversies. JAMA. 1993 Jun 2;269(21):2749-53.

8. Haynes RB. ACP Journal Club's modus operandi (Editorial). Ann Intern Med. 1991;115:A14.

9. Rennie D, Flanagin A. Publication bias. The triumph of hope over experience. JAMA. 1992 Jan 15;267(3):411-2.