Evidence-based medicine

Evidence-based medicine (EBM) is "the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients."^[1] The aim of EBM is to integrate the experience of the clinician, the values of the patient, and the best available scientific information to guide decision-making about clinical management. The term was originally used to describe an approach to teaching the practice of medicine and improving decisions by individual physicians about individual patients.^[2]

"Science-based medicine" redirects here. For the website, see Science-Based Medicine.

The EBM Pyramid is a tool that helps in visualizing the hierarchy of evidence in medicine, from least authoritative, like expert opinions, to most authoritative, like systematic reviews.^[3]

Methods[edit]

Steps[edit]

The steps for designing explicit, evidence-based guidelines were described in the late 1980s: formulate the question (population, intervention, comparison intervention, outcomes, time horizon, setting); search the literature to identify studies that inform the question; interpret each study to determine precisely what it says about the question; if several studies address the question, synthesize their results (meta-analysis); summarize the evidence in evidence tables; compare the benefits, harms and costs in a balance sheet; draw a conclusion about the preferred practice; write the guideline; write the rationale for the guideline; have others review each of the previous steps; implement the guideline.^[20]

For the purposes of medical education and individual-level decision making, five steps of EBM in practice were described in 1992^[55] and the experience of delegates attending the 2003 Conference of Evidence-Based Health Care Teachers and Developers was summarized into five steps and published in 2005.^[56] This five-step process can broadly be categorized as follows:

Research produced by EBM, such as from (RCTs), may not be relevant for all treatment situations.^[84] Research tends to focus on specific populations, but individual persons can vary substantially from population norms. Because certain population segments have been historically under-researched (due to reasons such as race, gender, age, and co-morbid diseases), evidence from RCTs may not be generalizable to those populations.^[85] Thus, EBM applies to groups of people, but this should not preclude clinicians from using their personal experience in deciding how to treat each patient. One author advises that "the knowledge gained from clinical research does not directly answer the primary clinical question of what is best for the patient at hand" and suggests that evidence-based medicine should not discount the value of clinical experience.^[65] Another author stated that "the practice of evidence-based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research."^[1]

randomized controlled trials

Use of evidence-based guidelines often fits poorly for complex, multimorbid patients. This is because the guidelines are usually based on clinical studies focused on single diseases. In reality, the recommended treatments in such circumstances may interact unfavorably with each other and often lead to polypharmacy.^[87]

[86]

The theoretical ideal of EBM (that every narrow clinical question, of which hundreds of thousands can exist, would be answered by and systematic reviews of multiple RCTs) faces the limitation that research (especially the RCTs themselves) is expensive; thus, in reality, for the foreseeable future, the demand for EBM will always be much higher than the supply, and the best humanity can do is to triage the application of scarce resources.

meta-analysis

Research can be influenced by biases such as political or ,^[88]^[89] publication bias and conflict of interest in academic publishing. For example, studies with conflicts due to industry funding are more likely to favor their product.^[90]^[91] It has been argued that contemporary evidence based medicine is an illusion, since evidence based medicine has been corrupted by corporate interests, failed regulation, and commercialisation of academia.^[92]

belief bias

Systematic Reviews methodologies are capable of bias and abuse in respect of (i) choice of inclusion criteria (ii) choice of outcome measures, comparisons and analyses (iii) the subjectivity inevitable in Risk of Bias assessments, even when codified procedures and criteria are observed.^[94]^[95] An example of all these problems can be seen in a Cochrane Review,^[96] as analyzed by Edmund J. Fordham, et al. in their relevant review.^[93]

[93]

A lag exists between when the RCT is conducted and when its results are published.

[97]

A lag exists between when results are published and when they are properly applied.

[98]

(the absence of a simple, consolidated mental framework into which new information can be placed) can hinder the application of EBM.^[99]

Hypocognition

: while patient values are considered in the original definition of EBM, the importance of values is not commonly emphasized in EBM training, a potential problem under current study.^[100]^[101]^[102]

Values

There are a number of limitations and criticisms of evidence-based medicine.^[79]^[80]^[81] Two widely cited categorization schemes for the various published critiques of EBM include the three-fold division of Straus and McAlister ("limitations universal to the practice of medicine, limitations unique to evidence-based medicine and misperceptions of evidence-based-medicine")^[82] and the five-point categorization of Cohen, Stavri and Hersh (EBM is a poor philosophic basis for medicine, defines evidence too narrowly, is not evidence-based, is limited in usefulness when applied to individual patients, or reduces the autonomy of the doctor/patient relationship).^[83]

In no particular order, some published objections include:

A 2018 study, "Why all randomised controlled trials produce biased results", assessed the 10 most cited RCTs and argued that trials face a wide range of biases and constraints, from trials only being able to study a small set of questions amenable to randomisation and generally only being able to assess the average treatment effect of a sample, to limitations in extrapolating results to another context, among many others outlined in the study.^[79]

Application of evidence in clinical settings[edit]

Despite the emphasis on evidence-based medicine, unsafe or ineffective medical practices continue to be applied, because of patient demand for tests or treatments, because of failure to access information about the evidence, or because of the rapid pace of change in the scientific evidence.^[103] For example, between 2003 and 2017, the evidence shifted on hundreds of medical practices, including whether hormone replacement therapy was safe, whether babies should be given certain vitamins, and whether antidepressant drugs are effective in people with Alzheimer's disease.^[104] Even when the evidence unequivocally shows that a treatment is either not safe or not effective, it may take many years for other treatments to be adopted.^[103]

There are many factors that contribute to lack of uptake or implementation of evidence-based recommendations.^[105] These include lack of awareness at the individual clinician or patient (micro) level, lack of institutional support at the organisation level (meso) level or higher at the policy (macro) level.^[106]^[107] In other cases, significant change can require a generation of physicians to retire or die and be replaced by physicians who were trained with more recent evidence.^[103]

Physicians may also reject evidence that conflicts with their anecdotal experience or because of cognitive biases – for example, a vivid memory of a rare but shocking outcome (the availability heuristic), such as a patient dying after refusing treatment.^[103] They may overtreat to "do something" or to address a patient's emotional needs.^[103] They may worry about malpractice charges based on a discrepancy between what the patient expects and what the evidence recommends.^[103] They may also overtreat or provide ineffective treatments because the treatment feels biologically plausible.^[103]

It is the responsibility of those developing clinical guidelines to include an implementation plan to facilitate uptake.^[108] The implementation process will include an implementation plan, analysis of the context, identifying barriers and facilitators and designing the strategies to address them.^[108]

Education[edit]

Training in evidence based medicine is offered across the continuum of medical education.^[56] Educational competencies have been created for the education of health care professionals.^[109]^[56]^[110]

The Berlin questionnaire and the Fresno Test^[111]^[112] are validated instruments for assessing the effectiveness of education in evidence-based medicine.^[113]^[114] These questionnaires have been used in diverse settings.^[115]^[116]

A Campbell systematic review that included 24 trials examined the effectiveness of e-learning in improving evidence-based health care knowledge and practice. It was found that e-learning, compared to no learning, improves evidence-based health care knowledge and skills but not attitudes and behaviour. No difference in outcomes is present when comparing e-learning with face-to-face learning. Combining e-learning and face-to-face learning (blended learning) has a positive impact on evidence-based knowledge, skills, attitude and behavior.^[117] As a form of e-learning, some medical school students engage in editing Wikipedia to increase their EBM skills,^[118] and some students construct EBM materials to develop their skills in communicating medical knowledge.^[119]