Evidence-based medicine (EBM) refers to the conscientious, explicit and judicious use of current best evidence in making decisions about the care of patients.
It integrates individual clinical expertise with the best available external clinical evidence from systematic research to guide decision-making.
Evidence-based medicine (EBM) is an approach to medical practice that emphasizes the use of the best available evidence from clinical research, combined with clinical expertise and patient values, to make decisions about the care of individual patients.
The goal of EBM is to improve patient outcomes by integrating scientific evidence into the decision-making process
It is a tool that helps in visualizing the hierarchy of evidence in medicine, from the least authoritative expert opinions, to most authoritative, like systematic reviews.
It uses of mathematical estimates of the risk of benefit and harm, derived from high-quality research on population samples, to inform clinical decision-making in the diagnosis, investigation or management of individual patients.
It is the process of finding, appraising, and using contemporaneous research findings as the basis for medical decisions.
Evidence-based medicine is described as the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients, and integrating individual clinical expertise with the best available external clinical evidence from systematic research.
Evidence-based medicine aims to make individual decision making more structured and objective, noting better research evidence.
Population-based data are applied to the care of an individual patient.
Evidence-based medicine share an emphasis on the importance of incorporating evidence from formal research in medical policies and decisions.
A distinction is sometimes made between evidence-based medicine and science-based medicine, which also takes into account factors such as prior plausibility and compatibility with established science.
Evidence-based guidelines and policies may not readily coordinate with experience-based practices orientated towards ethical clinical judgement, and can lead to contradictions, contest, and unintended crises.
Evidence-based guidelines may provide the basis for governmentality in health care.
Previous systematic reviews of 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.
Evidence-based medicine categorizes different types of clinical evidence and rates or grades them based on the strength of their freedom from the various biases.
The strongest evidence for therapeutic interventions is provided by systematic review of randomized, well-blinded, placebo-controlled trials with allocation concealment and complete follow-up 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, and biases inherent in observation and reporting of cases, and difficulties in ascertaining who is an expert.
The U.S. Preventive Services Task Force (USPSTF) put forth the following system grading and assessing the quality of evidence.
Level I: Evidence obtained from at least one properly designed randomized controlled trial. Level II-1: Evidence obtained from well-designed controlled trials without randomization. Level II-2: Evidence obtained from well-designed cohort studies or case-control studies, preferably from more than one center or research group. Level II-3: Evidence obtained from multiple time series designs 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.
Randomized controlled trials that have low risk of bias.
Observational studies have high risk of bias.
With randomized controlled trials, the quality of evidence is high but can be downgraded by five different ways.
Risk of bias: A judgment made on the basis of the chance that bias in included studies has influenced the estimate of effect.
Imprecision: A judgment made on the basis of the chance that the observed estimate of effect could change completely.
Indirectness: A judgment made on the basis of the differences in characteristics of how the study was conducted and how the results are actually going to be applied.
Inconsistency: A judgment made on the basis of the variability of results across the included studies.
Publication bias: A judgment made on the basis of the question whether all the research evidence has been taken to account.
The value of evidence is graded as high, moderate, or low grade.
Level A: Good scientific evidence suggests that the benefits of the clinical service substantially outweigh the potential risks.
Level B: At least fair scientific evidence suggests that the benefits of the clinical service outweighs the potential risks.
Level C: At least fair scientific evidence suggests that the clinical service provides benefits, but the balance between benefits and risks is too close for general recommendations.
Level D: At least fair scientific evidence suggests that the risks of the clinical service outweigh potential benefits.
Level I: Scientific evidence is lacking, of poor quality, or conflicting, such that the risk versus benefit balance cannot be assessed.
Leads to the development of clinical guidelines intended to provide recommendations aimed at optimizing patient care by summarizing and evaluating the available evidence supporting or refuting the use of diagnostic studies for therapeutic approaches.
Recommendation categories are based on evidence type, balance between desirable and undesirable effects, values and preferences, and resource allocation.
Randomized controlled trial‘s and meta-analyses are the major tools of evidence-based medicine and the source of the evidence that describes results for patients.
Category A recommendation: applies to all persons, and most patients should receive the recommended course of action.
Category B recommendation: individual decision making the deal: different choices will be appropriate for different patients.
Evidence type is based on study designs as well as a function of limitations in study design or implementation, imprecision of estimates, variability in findings, indirectness of evidence, publication bias, magnitude of treatment effects, dose response gradient, and constellation of plausible biases that could change effects.
Type I evidence: randomized clinical trial of overwhelming evidence from observational studies.
Type 2 evidence: randomized clinical trials with important limitations or exceptionally strong evidence from observational studies.
Type 3 evidence: observational studies in randomized clinical trials with notable limitation.
Type 4 evidence: clinical experience and observations, observational studies with important limitations, or randomized clinical trials with several major limitations.
Criteria used are the balance between desirable and undesirable effects the quality of the evidence, values and preferences and costs.
Evidence-based medicine include:
Formulating a clear clinical question
Searching for the best evidence from systematic reviews, randomized controlled trials, and other high-quality research studies that address the clinical question.
Critical appraisal of the evidence by evaluating the validity, reliability, and applicability of the findings to ensure they are relevant to the patient’s situation.
Integrating evidence with one’s clinical expertise:
EBM is essential to improving healthcare quality and ensuring that clinical practices are based on the most reliable evidence available.
EBM reflects Bayes’ theorem: the differences in likelihood ratio between clinical tests can be used to prioritize clinical tests according to their usefulness in a given clinical situation.
AUC-ROC The area under the receiver operating characteristic curve (AUC-ROC) reflects the relationship between sensitivity and specificity for a given test.
Number needed to treat (NNT)/Number needed to harm (NNH).
Number needed to treat is the number of people who need to be treated in order to achieve the desired outcome in one patient.
If treatment increases the chance of survival by 5%, then 20 people need to be treated in order for 1 additional patient to survive because of the treatment.
The concept can also be applied to diagnostic tests.
EBM attempts to objectively evaluate the quality of clinical research by critically assessing techniques reported by researchers in their publications.
High-quality studies have clearly defined eligibility criteria and have minimal missing data.
Studies may only be applicable to narrowly defined patient populations and may not be generalizable to other clinical contexts.
Sufficient time for defined outcomes to occur can influence the prospective study outcomes and the statistical power of a study to detect differences between a treatment and control arm.
A negative study may reflect a lack of benefit, or simply a lack of sufficient quantities of patients to detect a difference.
There are a number of limitations and criticisms of evidence-based medicine.
Evidence-based, is limited in usefulness when applied to individual patients, or reduces the autonomy of the doctor/patient relationship.
Research tends to focus on specific populations, but individual persons can vary substantially from population norms.
Certain population have been historically under-researched due to race, gender, age, and co-morbid diseases), evidence from RCTs may not be generalizable to those populations.
EBM applies to groups of people, but should not preclude clinicians from using their personal experience in deciding how to treat each patient.
Evidence-based medicine should not discount the value of clinical experience.
The practice of evidence-based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research.
Use of evidence-based guidelines often fits poorly for complex, multimorbid patients, because the guidelines are usually based on clinical studies focused on single diseases.
Research can be influenced by biases such as political or belief bias, publication bias and conflict of interest in academic publishing.
It is argued that contemporary evidence based medicine is an illusion, since evidence based medicine has been corrupted by corporate interests, failed regulation, and commercialization of academia.
Systematic Reviews 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.
Despite the emphasis on evidence-based medicine, unsafe or ineffective medical practices continue to occur, because of patient demand for tests or treatments, failure to access the evidence, or because of the rapid pace of change in the scientific evidence.
Factors that contribute to lack of uptake or implementation of evidence-based recommendations: lack of awareness at the individual clinician or patient, lack of institutional support at the organisation level, significant change can require a generation of physicians to retire or die and be replaced by physicians who were trained with more recent evidence.
Physicians may reject evidence that conflicts with their anecdotal experience or because of cognitive biases.
Tendency to over treat or do something or to address a patient’s emotional needs.
There may be over treatment or provision of ineffective treatments because the treatment feels biologically plausible.