Steurer, Johann

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PERSPECTIVESTransformation of evidence to knowledge: a neglected taskwithin the medical professionJohann SteurerPublished online: 11 October 2009# ISS 2009The term evidence-based medicine (EBM) was first used ina paper published in JAMA in 1992 [1]. In the bookEvidence-based medicine: how to practice and teach EBM,EBM was defined as the “conscientious, explicit, andjudicious use of current best evidence in making decisionsabout the care of individual patients” [2]. This was not anew concept at the time. Physicians caring for patientsbefore the era of EBM presumably also made use of thebest available evidence. What made EBM a new paradigmfor medical practice was the description of four steps thatphysicians should follow in order to practice evidence-based medicine: (1) physicians should formulate a specificand clinically relevant question and then (2) quickly andeffectively search for the best available evidence. (3) Oncethey have critically appraised the validity and utility of theevidence, (4) they should apply the findings of their criticalappraisal in clinical practice.The idea of EBM disseminated rapidly throughout theworld; new institutions were established, and specializedEBM journals were launched. There are two reasons forthis rapid dissemination: first, the tremendous increase inthe number of published papers, and second, the decline intrust toward ‘experts’ and authority. Up until half a centuryago, only a few clinical trials measuring clinically relevantoutcomes had been produced. Since then, more than100,000 randomized controlled trials have been published;approximately 12,000 were published in 2008 alone.Furthermore, the results of several cohort, case-control,and other types of studies lower on the EBM hierarchy havebeen reported. It has become quite impossible for aphysician to identify all of the relevant papers for his orher specialty, not to mention to read them, in order to keepup to date. The intention of the founders of EBM was toenable physicians to identify relevant research articles andto critically appraise the original literature with the hope ofmaking them more independent of the opinions and beliefsof the prevailing experts.The rank and high standing of medical experts wasanathema to the founders of EBM. Medical experts arethose who state their beliefs and opinions at medicalconferences and in review articles. Among the weaknessesthat they may fall prey to are the selective citing of researchresults, inappropriate judgments regarding the methodolog-ical quality of cited papers, and the formulation ofconclusions and recommendations that are not supportedby the available evidence [3]. Furthermore, suspicions thatfinancial relationships between experts and pharmaceuticalcompanies might have an impact on the conclusions andrecommendations reached by experts is common and notentirely unwarranted. Stelfox et al. showed that experts whorecommend calcium-channel antagonists for the treatmentof high blood pressure are significantly more likely thanneutral authors to have financial ties with manufacturers ofthese drugs [4]. Not surprisingly, examples such as thishave led to an even greater loss of trust in experts.One of the most important and sustainable effects of theEBM initiative was, and still is, the advancement ofmethods to synthesize the available evidence systematicallyand transparently. The results of single studies are oftenimprecise, and the results of different studies on the sameobject may differ substantially. Systematic reviews andmeta-analyses allow entire bodies of evidence to beassessed. The Cochrane Collaboration and independentresearchers working outside the Cochrane CollaborationJ. Steurer (*)Horten Centre for Patient Oriented Research and KnowledgeTransfer,Raemistrasse 100,8091 Zürich, Switzerlande-mail: johann.steurer@usz.chSkeletal Radiol (2010) 39:1–3DOI 10.1007/s00256-009-0812-9deserve much credit for developing and critically improvingmethods to synthesize evidence from different sources.Today, meta-analyses are performed by combining data notonly at the level of study results, but also at the level ofindividual patients. Network meta-analyses are a recentadvancement in the field; they assess the relative effective-ness of different treatments that have not been compareddirectly in randomized controlled trials [5]. Systematicreviews are meant to support “busy clinicians seekingbottom lines,” so that they will not have to rely uponreviews by so-called experts or information sponsored bymanufacturers of drugs/medical devices and can find “briefbut valid summaries of best evidence” [2].When we take a critical look at the promises made byproponents of EBM, we see that they have only partly beenfulfilled. Clinicians and policy makers do not use system-atic reviews as often as expected. Systematic reviews areoften too long and detailed for busy clinicians to read;additionally, they do not provide the clinician with therelevant information. A survey performed by Glasziou et al.revealed that fewer than 15% of the systematic reviewspublished in Evidence based medicine provided sufficientinformation about the intervention to allow clinicians toimplement it [6]. The conclusions of systematic reviewsoften state that the available evidence is inconclusive andthat further studies must be performed. This is good newsfor researchers, but not very helpful for physicians caringfor patients. The following is a typical example: the authorsof a systematic review wanted to evaluate whether resectionof the colon should be done primarily or as a stagedprocedure in patients with obstruction from left colorectalcarcinoma. The main result reported by the authorsreads “We identified 2,043 citations. One study forpotential inclusion was identified, but was then excluded.”The conclusion was “ the limited number of identifiedstudies … do not allow a reliable assessment of the role ofeither therapeutic strategy … it would appear advisable toconduct high quality large scale RCT to establish whichtreatment is more effective” [7].Without a doubt, most researchers performing systematicreviews search carefully for the relevant literature indifferent databases, contact researchers to retrieve informa-tion not reported in the published papers, and try to obtainunpublished studies from drug and medical device compa-nies. However, despite methodological advancements inmerging primary study results into systematic reviews,major problems persist. Varying enrollment criteria inprimary studies, differences in the definition and assess-ment of clinical outcomes, and the measurement of theoutcome at varying time points hamper the pooling ofdifferent studies. The consequence is that even the results ofsystematic reviews on one and the same topic may beinconsistent.This problem is exemplified in the article by Petersonand Hodler in this journal on the use of therapeuticinjections for the spine and sacroiliac joints. A systematicreview evaluating the benefit of injections in the facet jointsof the lumbar spine concluded that there is moderateevidence that this therapy is effective in providing painrelief. Two other reviews came to the conclusion that thereis no strong evidence for or against the use of injectiontherapy. Such inconsistencies are a matter of fact. Forphysicians and policy makers, such conflicting results andconclusions are not helpful; nor is the recommendation thatfurther studies should be done.Therefore, the solution is to establish a knowledge base ofmedicine from which physicians can draw the informationthat they need to care for patients [8]. A collection of evidencein the form of systematic reviews and the results ofrandomized trials or other clinical studies may not besufficient. The crucial step is the transformation of evi-dence—the results of research—into knowledge. This is atask that should be undertaken by experts. Experts in aclinical specialty or subspecialty, in cooperation with expertsin research methodology and statistics, would be competentto establish this knowledge base.A prevailing characteristic trait of the EBM movement isthe ambiguous and occasionally negative attitude towardexpert opinions. Various scales for grading the levels ofevidence have been developed and disseminated within thepast decade. To my knowledge, in all of them, expertopinions lag behind single case reports in terms oftrustworthiness. According to the recommendations of theOxford Centre for Evidence-Based Medicine [9] regardingstudies of prognosis, the highest level of evidence is asystematic review of randomized controlled trials, followedby single randomized trials, and cohort and other studydesigns. Expert opinions follow poor-quality cohort studies.The categorization and grading of evidence levels isbased on study design, and experts do not belong in thiscategory. An expert should be a person of integrity with ahigh degree of knowledge about a certain subject. Expertopinions cannot be a substitute for the results of arandomized controlled trial or other carefully planned andexecuted studies, but expert knowledge is essential when anentire body of evidence is being assessed and evidence, theresults of research, is being transformed to knowledge. Theresult of this process would be the knowledge base ofmedicine, which physicians could trust and rely upon.Knowledge in this context is defined as the shared beliefsof experts.Carefully planned and executed primary studies andsystematic reviews are a first and essential step in establish-ing the knowledge base, but the process should not stopthere. I propose that a panel of experts in a specific field,for example, diagnostic and therapeutic injections for2 Skeletal Radiol (2010) 39:1–3patients with joint and back pain, come together toappraise, discuss, and weigh the available evidence andthen draw up a ‘shared expert opinion.’ The purpose ofsuch a panel would not be to reach consensus on the leastcommon denominator, and the desired result would not be arecommendation for what physicians should do. The resultcould be a publication, including a detailed description, asspecific as possible, about the consequences in terms ofprobabilities. For example, the outcome of injections in thesacro-iliac joint of patients with chronic low back painbelow L5 would be compared to the outcomes of othertreatment modalities. This panel would provide knowledge-oriented guidance rather than action-oriented guidelinestelling physicians and/or patients what they should do.Physicians would be able to provide patients with valuableinformation, and patients would be empowered to makeinformed decisions.Specific considerations for further research could be anadditional achievement of the panel. An obvious difficultywhen one is evaluating the effect of treatment on patientswith low back pain concerns the question of which patientsto enroll in studies. In contrast with patients who have had amyocardial infarction, many patients with low back painhave structural or functional anomalies underlying theirsymptoms that are unknown. Researchers are trying toovercome this difficulty by identifying variables that willallow them to characterize these patients more accurately.One treatment modality is an injection of analgesics into thesacro-iliac joint or the surrounding structures in patientswith chronic low back pain below L5. The rationale is thatpatients for whom pain decreases or disappears after theanalgesics injection have a higher probability of benefitingfrom a therapeutic injection with steroids into the samejoint. Comparisons of different studies reveal that nouniform technique was used and that different criteria wereapplied to judge whether pain arose from the sacro-iliacjoint or elsewhere [10]. Therefore, those patients that wereincluded in the studies assessing the effect of therapeuticinjections with steroids might have differed with respect tothe underlying causes of low back pain. Shared recom-mendations from experts regarding which test to utilize andhow to measure the effect of diagnostic injections would behelpful for directing the planning and execution of furthertrials. In future systematic reviews, this will make it easierfor study results to be compared and pooled.Evidence is not synonymous with knowledge. Evidenceis the result of research, and knowledge is, when based onreliable evidence, “shared expert beliefs.” After the shun-ning of experts and authorities by the EBM movement, it istime to allow experts—impartial, objective persons ofintegrity with a high degree of knowledge in their field—to return and establish the knowledge base of medicine.References1. Evidence-Based Medicine Working Group, Guyatt G, Cairns J,Churchill D, Cook D, Haynes B, et al. Evidence-based medicine.A new approach to teaching the practice of medicine. JAMA.1992;268:2420–5.2. Sackett DL, Richardson WS, Rosenberg W, Haynes RB.Evidence-based medicine. How to practice and teach EBM.New York: Churchill Livingstone; 1997.3. Oxman AD, Guyatt GH. The science of reviewing research. AnnN Y Acad Sci. 1993;703:125–33.4. Stelfox HT, Chua G, O’Rourke K, Detsky AS. Conflict of interestin the debate over calcium-channel antagonists. N Engl J Med.1998;338:101–6.5. Lumley T. Network meta-analysis for indirect treatment compar-isons. Stat Med. 2002;21:2313–24.6. Glasziou P, Meats E, Heneghan C, Shepperd S. What is missingfrom descriptions of treatment in trials and reviews? BMJ.2008;336:1472–4.7. De Salvo GL, Gava C, Lise M, Pucciarelli S. Curative surgery forobstruction from primary left colorectal carcinoma: Primary orstaged resection? Cochrane Database Syst Rev. 2004;(2):CD002101.8. Miettinen OS. Knowledge base of scientific gnosis: IV. Knowl-edge base of scientific gnosis vis-a-vis evidence base of this. JEval Clin Pract. 2004;10:365–7.9. Howick J. Oxford Centre for Evidence-Based medicine. Levels ofevidence. 2009. http://www.cebm.net/index.aspx?o=1025.Accessed 8 September 200910. Rupert MP, Lee M, Manchikanti L, Datta S, Cohen SP. Evaluationof sacroiliac joint interventions: a systematic appraisal of theliterature. Pain Physician. 2009;12:399–418.Skeletal Radiol (2010) 39:1–3 3

Transformation of evidence to knowledge: a neglected task within the medical profession

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Transformation of evidence to knowledge: a neglected task within the medical profession

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