Anesth Analg 2002;95:1817-1818
© 2002 International Anesthesia Research Society
LETTERS TO THE EDITOR
Evidence-Based Medicine Needs Proper Critical Review
Neville W. Goodman, DPhil FRCA
Southmead Hospital, Bristol, UK
To the Editor: Proponents of evidence-based medicine (EBM) insist that reviewers search thoroughly for all evidence relevant to a clinical question. Yet when reviewing the subject of EBM itself, these same proponents seem curiously blind to criticism. In their "review," Pronovost et al. (1) do not review the considerable academic debate that there has been over EBM; they merely describe what EBM is, and how anesthetists should go about it. At the very least, they should have cited Horan’s editorial (2), and answered the points he made.
No one argues against using evidence when choosing treatments; the disagreements arise when we consider what evidence is appropriate. Pronovost et al. rightly state that the philosophical foundation for EBM is clinical epidemiology—but this is the core of the problem. As Charlton pointed out (3,4), and as I have cited before (5), epidemiology does not provide the information necessary to treat individuals. There are also difficulties with randomized controlled trials (6), to which EBM—even if it does include other forms of evidence—tends to give precedence.
There is no space in a letter to present arguments in detail, but there is plenty of material for interested readers, for example (7–11). It is a shame that Pronovost et al. did not cite any at all; Greenhalgh (12)—also an enthusiast for evidence-based medicine—managed to do so in a recent essay.
An irony of evidence-based medicine is that it claims to be nonauthoritarian; unlike the old authority of expert-based medicine, anyone can learn the techniques, and therefore anyone can apply them. But the reality is that individual practitioners do not have the time to apply EBM to every clinical question, and therefore have to rely on EBM as the new authority. It is an added irony that Pronovost et al. cite, as a source for "well described methods for their conduct," the Cochrane systematic review of the use of albumin. This review was severely criticized at the time (13), and later by Horsey (14), who reexamined the included trials, and was also critical that the reviewing group did not include an intensive care clinician.
Pronovost et al. cite a paper (15) that is a light-hearted summary of alternatives to EBM such as "eminence-based medicine," a paper that has a footnote in which the authors explicitly state that they each contributed half the jokes. This is a variation on what Shahar (16) wrote was the most common method of responding to criticism of EBM: turning a deaf ear.
References
- Pronovost PJ, Berenholtz SM, Dorman T, et al. Evidence-based medicine in anesthesiology. Anesth Analg 2001; 92: 787–94.[Free Full Text]
- Horan BF. Evidence-based medicine and anaesthesia: uneasy bedfellows? Anaesth Intensive Care 1997; 25: 679–85.[Medline]
- Charlton BG. The scope and nature of epidemiology. J Clin Epidemiol 1996; 49: 623–6.[Web of Science][Medline]
- Charlton BG. Restoring the balance: evidence-based medicine put in its place. J Eval Clin Pract 1997; 3: 87–98.[Medline]
- Goodman NW. Anaesthesia and evidence-based medicine. Anaesthesia 1998; 53: 353–68.[Medline]
- Feinstein AR, Horwitz RI. Problems in the "evidence" of "evidence-based medicine." Am J Med 1997; 103: 529–35.[Web of Science][Medline]
- LeLorier J, Grégoire G, Benhaddad A, et al. Discrepancies between meta-analyses and subsequent large randomized, controlled trials. N Engl J Med 1997; 337: 536–42.[Abstract/Free Full Text]
- Bailar JC III. The promise and problems of meta-analysis. N Engl J Med 1997; 337: 559–61.[Free Full Text]
- Black D. The limitations of evidence. J Roy Coll Phys Lond 1998; 32: 23–36.[Web of Science][Medline]
- Couto JS. Evidence-based medicine: a Kuhnian perspective of a transvestite non-theory. J Eval Clin Pract 1999; 4: 267–75.
- Rees J. Evidence-based medicine: the epistemiology that isn’t. J Am Acad Dermatol 2000; 43: 727–9.[Medline]
- Greenhalgh T. Intuition and evidence: uneasy bedfellows. Br J Gen Pract 2002; 52: 395–400.[Web of Science][Medline]
- Swales JD. The troublesome search for evidence: three cultures in need of integration. J R Soc Med 2000; 93: 402–7.[Free Full Text]
- Horsey P. Albumin and hypovolaemia: is the Cochrane evidence to be trusted? Lancet 2002; 359: 70–2.[Web of Science][Medline]
- Isaacs D, Fitzgerald D. Seven alternatives to evidence-based medicine. BMJ 1999; 281: 714–9.
- Shahar E. Evidence-based medicine: a new paradigm or the emperor’s new clothes? J Eval Clin Pract 1999; 4: 277–82.
Response
Peter Pronovost, MD PhD,
Sean Berenholtz, MD,
Todd Dorman, MD,
Elizabeth Martinez, MD, and
William Merritt, MD
Anesthesiology/Critical Care Med, Surgery and Health Policy & Management, The Johns Hopkins University School of Medicine, Baltimore, MD
In Response: Dr. Goodman appropriately points out that our article on evidence-based medicine (EBM) did not include references to the literature he and others published on the academic debate surrounding EBM (1–4). Our goal was not to conduct a systematic review of the evidence regarding EBM, but rather to present an overview of EBM and how it might be applied. This omission highlights the need for a structured process for the conduct and review of systematic reviews as proposed by proponents of EBM.
EBM is intended to provide busy clinicians with tools to aid in the care of patients. These tools need to be combined with clinical experience and patient preferences. It is unlikely that valid evidence will exist to inform the majority of clinical decisions confronting busy providers. In the absence of evidence or time, providers will need to rely on personal experience and pathophysiologic reasoning to inform their practice. In addition, the Cochrane review of albumin was criticized largely for the quality of the available literature rather than the quality of the conduct of the review.
We thank Dr. Goodman for reminding us of the limitations of EBM and helping us to remember what EBM is not (5). We take a less proscriptive view of EBM than Dr. Goodman believing EBM is a set of tools to assist providers in caring for patients. Nonetheless, it is important for us to remember that evidence alone is insufficient to ensure that patients receive that care they should receive and no more (6). We need to ensure that knowledge of what do to is translated into action.
References
- Horan BF. Evidence-based medicine and anaesthesia: uneasy bedfellows? Anaesth Intensive Care 1997; 25: 679–85.
- Charlton BG. The scope and nature of epidemiology. J Clin Epidemiol 1996; 49: 623–6.
- Charlton BG. Restoring the balance: evidence-based medicine put in its place. J Eval Clin Pract 1997; 3: 87–98.
- Goodman NW. Anaesthesia and evidence-based medicine. Anaesthesia 1998; 53: 353–68.
- Sackett DL, Rosenberg WM, Gray JA, et al. Evidence-based medicine: what it is and what it isn’t. BMJ 1996; 312: 71–2.[Free Full Text]
- Jencks SF, Cuerdon T, Burwen DR, et al. Quality of medical care delivered to Med beneficiaries: a profile at state and national levels. JAMA 2000; 284: 1670–6.[Abstract/Free Full Text]
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