Evidence-based medicine (EBM) aims to apply the best available evidence Evidence in its broadest sense includes everything that is used to determine or demonstrate the truth of an assertion. Giving or procuring evidence is the process of using those things that are either presumed to be true, or (b) were themselves proven via evidence, to demonstrate an assertion's truth. Evidence is the currency by which one fulfills gained from the scientific method Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering observable, empirical and measurable evidence subject to specific principles of reasoning. A scientific method consists of to medical decision making Decision making can be regarded as the mental processes resulting in the selection of a course of action among several alternatives. Every decision making process produces a final choice. The output can be an action or an opinion of choice.[1] It seeks to assess the strength of evidence of the risks and benefits of treatments Therapy , or treatment, is the attempted remediation of a health problem, usually following a diagnosis. In the medical field, it is synonymous with the word "treatment". Among psychologists, the term may refer specifically to psychotherapy or "talk therapy" (including lack of treatment) and diagnostic tests.[2]
EBM recognizes that many aspects of medical care depend on individual factors such as quality- The term quality of life is used to evaluate the general well-being of individuals and societies. The term is used in a wide range of contexts, including the fields of international development, healthcare, and political science. Quality of life should not be confused with the concept of standard of living, which is based primarily on income and value-of-life The value of life is an economic value assigned to life in general, or to specific living organisms. In social and political sciences, it is the marginal cost of death prevention in a certain class of circumstances. As such, it is a statistical term, the cost of reducing the (average) number of deaths by one. It is an important issue in a wide judgments, which are only partially subject to scientific methods. EBM, however, seeks to clarify those parts of medical practice that are in principle subject to scientific methods and to apply these methods to ensure the best prediction A prediction or forecast is a statement about the way things will happen in the future, often but not always based on experience or knowledge. While there is much overlap between prediction and forecast, a prediction may be a statement that some outcome is expected, while a forecast may cover a range of possible outcomes of outcomes in medical treatment, even as debate continues about which outcomes are desirable.
Classification
Two types of evidence-based medicine have been proposed.[3]
Evidence-based guidelines
Evidence-based guidelines (EBG) is the practice of evidence-based medicine at the organizational or institutional level. This includes the production of guidelines, policy, and regulations. This approach has also been called evidence based healthcare.[4]
Evidence-based individual decision making
Evidence-based individual decision (EBID) making is evidence-based medicine as practiced by the individual health care provider A health care provider or health professional is an organization or person who delivers proper health care in a systematic way professionally to any individual in need of health care services. There is concern that current evidence-based medicine focuses excessively on EBID.[5] The American Academy of Family Physicians (AAFP) has determined that DynaMed (http://www.ebscohost.com/dynamed) may be of assistance to family physicians in answering clinical questions with high-quality evidence.
Process and progress
Using techniques from science Science is, in its broadest sense, any systematic knowledge that is capable of resulting in a correct prediction or reliable outcome. In this sense, science may refer to a highly skilled technique, technology, or practice, engineering Engineering is the discipline, art and profession of acquiring and applying technical, scientific, and mathematical knowledge to design and implement materials, structures, machines, devices, systems, and processes that safely realize a desired objective or invention, and statistics Statistics is the formal science of making effective use of numerical data relating to groups of individuals or experiments. It deals with all aspects of this, including not only the collection, analysis and interpretation of such data, but also the planning of the collection of data, in terms of the design of surveys and experiments, such as meta-analysis In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. In its simplest form, this is normally by identification of a common measure of "effect size", for which a weighted average might be the output of a meta-analyses. Here the weighting might be related to sample sizes of medical literature Contemporary and historic views regarding diagnosis, prognosis and treatment of medical conditions have been documented for thousands of years. The Edwin Smith papyrus is the first known medical treatise. Initially most described inflictions related to warfare. This was because war was the most important part of society and it was the most common, risk-benefit analysis For research that involves more than minimal risk of harm to the subjects, the investigator must assure that the amount of benefit clearly outweighs the amount of risk. Only if there is favorable risk benefit ratio, a study may be considered ethical, and randomized controlled trials A randomized controlled trial is a type of scientific experiment most commonly used in testing the efficacy or effectiveness of healthcare services (such as medicine or nursing) or health technologies (such as pharmaceuticals, medical devices or surgery). RCTs involve the random allocation of different interventions (treatments or conditions) to (RCTs), EBM aims for the ideal that healthcare Health care or healthcare is the treatment and prevention of illness. Health care is delivered by professionals in medicine, dentistry, nursing, pharmacy and allied health professionals should make "conscientious, explicit, and judicious use of current best evidence" in their everyday practice. Ex cathedra Papal infallibility is the dogma in Roman Catholic theology that, by action of the Holy Spirit, the Pope is preserved from even the possibility of error when he solemnly declares or promulgates to the universal Church a dogmatic teaching on faith or morals as being contained in divine revelation, or at least being intimately connected to divine statements by the "medical expert An expert ( Audio (help·info)) is someone widely recognized as a reliable source of technique or skill whose faculty for judging or deciding rightly, justly, or wisely is accorded authority and status by their peers or the public in a specific well-distinguished domain. An expert, more generally, is a person with extensive knowledge or ability" are considered to be least valid form of evidence. All "experts" are now expected to reference their pronouncements to scientific studies.
The systematic review A systematic review is a literature review focused on a single question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. Systematic reviews of high-quality randomized controlled trials are crucial to evidence-based medicine. An understanding of systematic reviews and how to of published research studies is a major method used for evaluating particular treatments. The Cochrane Collaboration The Cochrane Collaboration is a group of over 27,000 volunteers in more than 90 countries who review the effects of health care interventions tested in biomedical randomized controlled trials. A few more recent reviews have also studied the results of non-randomized, observational studies. The results of these systematic reviews are published as & is one of the best-known, respected examples of systematic reviews. Like other collections of systematic reviews, it requires authors to provide a detailed and repeatable plan of their literature search and evaluations of the evidence. Once all the best evidence is assessed, treatment is categoried as "likely to be beneficial", "likely to be harmful", or "evidence did not support either benefit or harm".
A 2007 analysis of 1016 systematic reviews from all 50 Cochrane Collaboration Review Groups found that 44% of the reviews concluded that the intervention was "likely to be beneficial", 7% concluded that the intervention was "likely to be harmful", and 49% concluded that evidence "did not support either benefit or harm". 96% recommended further research.[6] A 2001 review of 160 Cochrane systematic reviews (excluding complementary treatments) in the 1998 database revealed that, according to two readers, 41.3% concluded positive or possibly positive effect, 20% concluded evidence of no effect, 8.1% concluded net harmful effects, and 21.3% of the reviews concluded insufficient evidence.[7] A review of 145 alternative medicine In Western culture, alternative "medicine" is any healing practice "that does not fall within the realm of conventional medicine", or "that which has not been shown consistently to be effective." It is often opposed to evidence based medicine and encompasses therapies with an historical or cultural, rather than a Cochrane reviews using the 2004 database revealed that 38.4% concluded positive effect or possibly positive (12.4%) effect, 4.8% concluded no effect, 0.69% concluded harmful effect, and 56.6% concluded insufficient evidence.[8]:135-136
Generally, there are three distinct, but interdependent, areas of EBM. The first is to treat individual patients with acute or chronic pathologies by treatments supported in the most scientifically valid medical literature. Thus, medical practitioners would select treatment options for specific cases based on the best research for each patient they treat. The second area is the systematic review A systematic review is a literature review focused on a single question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. Systematic reviews of high-quality randomized controlled trials are crucial to evidence-based medicine. An understanding of systematic reviews and how to of medical literature to evaluate the best studies on specific topics. This process can be very human-centered, as in a journal club A journal club is a group of individuals who meet regularly to critically evaluate recent articles in scientific literature. Journal clubs are usually organized around a defined subject in basic or applied research. For example, the application of evidence-based medicine to some area of medical practice can be facilitated by a journal club, or highly technical, using computer programs and information techniques such as data mining Data mining is the process of extracting patterns from data. Data mining is seen as an increasingly important tool by modern business to transform data into an informational advantage. It is currently used in a wide range of profiling practices, such as marketing, surveillance, fraud detection, and scientific discovery. Increased use of information technology Information technology is "the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware", according to the Information Technology Association of America (ITAA). IT deals with the use of electronic computers and computer software to turns large volumes of information into practical guides. Finally, evidence-based medicine can be understood as a medical "movement" in which advocates work to popularize the method and usefulness of the practice in the public, patient communities, educational institutions, and continuing education Continuing education is an all-encompassing term within a broad spectrum of post-secondary learning activities and programs. The term is used mainly in the United States and Canada. Recognized forms of post-secondary learning activities within the domain include: degree credit courses by non-traditional students, non-degree career training, of practicing professionals[citation needed].
Ranking the quality of evidence
Evidence-based medicine categorizes different types of clinical evidence and [1] them according to the strength of their freedom from the various biases that beset medical research. For example, the strongest evidence for therapeutic interventions is provided by systematic review of randomized A randomized controlled trial is a type of scientific experiment most commonly used in testing the efficacy or effectiveness of healthcare services (such as medicine or nursing) or health technologies (such as pharmaceuticals, medical devices or surgery). RCTs are also employed in other research areas, such as judicial, educational, and social, double-blind A blind or blinded experiment is a scientific experiment where some of the persons involved are prevented from knowing certain information that might lead to conscious or unconscious bias on their part, invalidating the results, placebo-controlled trials A Placebo-controlled study is a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed to have no real effect. Placebos are most commonly used in blinded trials, where subjects do involving a homogeneous patient population and medical condition. In contrast, patient testimonials, case reports, and even expert opinion have little value as proof because of the placebo effect, the biases inherent in observation and reporting of cases, difficulties in ascertaining who is an expert, and more.
US Preventive Services Task Force
Systems to stratify evidence by quality have been developed, such as this one by the U.S. Preventive Services Task Force The U.S. Preventive Services Task Force is "an independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services." The task force, a panel of experts, is funded and appointed by the government of the United States[citation for ranking evidence about the effectiveness of treatments or screening[citation needed]:
- Level I: Evidence obtained from at least one properly designed randomized controlled trial A randomized controlled trial is a type of scientific experiment most commonly used in testing the efficacy or effectiveness of healthcare services (such as medicine or nursing) or health technologies (such as pharmaceuticals, medical devices or surgery). RCTs involve the random allocation of different interventions (treatments or conditions) to.
- Level II-1: Evidence obtained from well-designed controlled trials without randomization Randomization is a core principle in statistical theory, whose importance was emphasized by Charles S. Peirce in "Illustrations of the Logic of Science" and "A Theory of Probable Inference" (1883). Randomization-based inference is especially important in experimental design and in survey sampling.
- Level II-2: Evidence obtained from well-designed cohort A cohort study or panel study is a form of longitudinal study used in medicine, social science and ecology. It is one type of study design and should be compared with a cross-sectional study or case-control Case-control is a type of retrospective, epidemiological, clinical study design. In a case-control study, people with a disease are matched with people who do not have the disease (the 'controls'). Further data is then collected on those individuals and the groups are compared to find out if other characteristics (perhaps a history of smoking) are analytic studies, preferably from more than one center or research group.
- Level II-3: Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled trials might also be regarded as this type of evidence.
- Level III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.
National Health Service
The UK National Health Service The National Health Service is the name commonly used to refer to the four single-payer publicly funded healthcare systems in the United Kingdom, collectively or individually, although only the health service in England uses the name 'National Health Service' without further qualification. The publicly-funded healthcare organisation in Northern uses a similar system with categories labeled A, B, C, and D. The above Levels are only appropriate for treatment or interventions; different types of research are required for assessing diagnostic accuracy or natural history and prognosis, and hence different "levels" are required. For example, the Oxford Centre for Evidence-based Medicine suggests levels of evidence (LOE) according to the study designs and critical appraisal of prevention, diagnosis, prognosis, therapy, and harm studies:[9]
- Level A: Consistent Randomised Controlled Clinical Trial A randomized controlled trial is a type of scientific experiment most commonly used in testing the efficacy or effectiveness of healthcare services (such as medicine or nursing) or health technologies (such as pharmaceuticals, medical devices or surgery). RCTs involve the random allocation of different interventions (treatments or conditions) to, cohort study A cohort study or panel study is a form of longitudinal study used in medicine, social science and ecology. It is one type of study design and should be compared with a cross-sectional study, all or none (see note below), clinical decision rule validated in different populations.
- Level B: Consistent Retrospective Cohort, Exploratory Cohort, Ecological Study, Outcomes Research, case-control study Case-control is a type of epidemiological study design. Case-control studies are used to identify factors that may contribute to a medical condition by comparing subjects who have that condition with patients who do not have the condition but are otherwise similar (the 'controls'); or extrapolations from level A studies.
- Level C: Case-series study or extrapolations from level B studies.
- Level D: Expert opinion without explicit critical appraisal, or based on physiology Physiology is the science of the functioning of living systems. It is a subcategory of biology. In physiology, the scientific method is applied to determine how organisms, organ systems, organs, cells and biomolecules carry out the chemical or physical function that they have in a living system. The word physiology is from Ancient Greek: φύσις, bench research or first principles.
GRADE Working Group
A newer system is by the GRADE Working Group and takes in account more dimensions that just the quality of medical evidence.[10] "Extrapolations" are where data is used in a situation which has potentially clinically important differences than the original study situation. Thus, the quality of evidence to support a clinical decision is a combination of the quality of research data and the clinical 'directness' of the data.[11]
Despite the differences between systems, the purposes are the same: to guide users of clinical research information about which studies are likely to be most valid. However, the individual studies still require careful critical appraisal.
Note: The all or none principle is met when all patients died before the Rx became available, but some now survive on it; or when some patients died before the Rx became available, but none now die on it.
Categories of recommendations
In guidelines and other publications, recommendation for a clinical service is classified by the balance of risk versus benefit of the service and the level of evidence on which this information is based. The U.S. Preventive Services Task Force The U.S. Preventive Services Task Force is "an independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services." The task force, a panel of experts, is funded and appointed by the government of the United States[citation uses:[12]
- Level A: Good scientific evidence suggests that the benefits of the clinical service substantially outweighs the potential risks. Clinicians should discuss the service with eligible patients.
- Level B: At least fair scientific evidence suggests that the benefits of the clinical service outweighs the potential risks. Clinicians should discuss the service with eligible patients.
- Level C: At least fair scientific evidence suggests that there are benefits provided by the clinical service, but the balance between benefits and risks are too close for making general recommendations. Clinicians need not offer it unless there are individual considerations.
- Level D: At least fair scientific evidence suggests that the risks of the clinical service outweighs potential benefits. Clinicians should not routinely offer the service to asymptomatic patients.
- Level I: Scientific evidence is lacking, of poor quality, or conflicting, such that the risk versus benefit balance cannot be assessed. Clinicians should help patients understand the uncertainty surrounding the clinical service.
Statistical measures
Evidence-based medicine attempts to express clinical benefits of tests and treatments using mathematical methods. Tools used by practitioners of evidence-based medicine include:
Likelihood ratio
Main article: Likelihood ratios in diagnostic testingThe pretest odds of a particular diagnosis, multiplied by the likelihood ratio, determines the post-test odds. (Odds can be calculated from, and then converted to, the [more familiar] probability.) This reflects Bayes' theorem In probability theory, Bayes' theorem, often called Bayes' law or Bayes' rule, and named after Rev. Thomas Bayes , shows how one conditional probability (such as the probability of a hypothesis given observed evidence) depends on its inverse (in this case, the probability of that evidence given the hypothesis). The differences in likelihood ratio between clinical tests can be used to prioritize clinical tests according to their usefulness in a given clinical situation.
Sat, 24 Jul 2010 07:27:53 GMT+00:00
PR Web (press release) ... FCAP, adding; This document will undoubtedly help providers of therapeutic apheresis to further the cause of evidence based medicine and help patients ...
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Wed, 28 Apr 2010 01:01:55 PDT
Doctors working in A&E departments hare warning that plans to downgrade some services are based on flawed evidence. The College of Emergency ... news.bbc.co.uk.
(Michael)
Sat, 24 Jul 2010 13:38:16 GM
Although I agree with much of the JNC 7 recommendations and strive to follow . evidence based medicine. , my concern is that these guidelines are considered by some to be chapter and verse. I'm concerned pay for performance will limit the ...
