EBM is the integration of clinical expertise, EBM is the integration of clinical expertise, patient values, and the best evidence into the patient values, and the best evidence into the decision making process for patient care. decision making process for patient care. Clinical expertise refers to the clinician's Clinical expertise refers to the clinician's cumulated experience, education and clinical cumulated experience, education and clinical skills. The patient brings to the encounter his or skills. The patient brings to the encounter his or her own personal and unique concerns, her own personal and unique concerns, expectations, and values. The best evidence is expectations, and values. The best evidence is usually found in clinically relevant research that usually found in clinically relevant research that has been conducted using sound methodology. has been conducted using sound methodology. (Sackett D, 2002)(Sackett D, 2002)

The Steps in the EBM ProcessThe Steps in the EBM Process

6. Evaluate your performance with this patientSelf-evaluation

5. Return to the patient -- integrate that evidence with clinical expertise, patient preferences and apply it to practice

The patient

4. Appraise that evidence for its validity (closeness to the truth) and applicability (usefulness in clinical practice)

The evaluation

3. Select the appropriate resource(s) and conduct a searchThe resource

2. Construct a well built clinical question derived from the case The question

1. Start with the patient -- a clinical problem or question arises out of the care of the patient

The patient

Two types of evidenceTwo types of evidence--based based medicine have been proposedmedicine have been proposed EvidenceEvidence--based guidelines based guidelines ((EBGEBG): ): is the is the

practice of evidencepractice of evidence--based medicine at the based medicine at the organizational or institutional levelorganizational or institutional level. . This includes This includes the production of guidelines, policy, and the production of guidelines, policy, and regulationsregulations. . This approach has also been called This approach has also been called evidence based ealthcareevidence based ealthcare

EvidenceEvidence--based individual decision based individual decision makingmaking((EBIDEBID): ): making is evidencemaking is evidence--based based medicine as practiced by the individualmedicine as practiced by the individual health care health care providerprovider. . There is concern that current evidenceThere is concern that current evidence--based medicine focuses excessively on EBIDbased medicine focuses excessively on EBID..

Medical guidelineMedical guideline

Modern clinical guidelines briefly identify, summarize and Modern clinical guidelines briefly identify, summarize and evaluate the best evidence and most current data aboutevaluate the best evidence and most current data about preventionprevention, , diagnosisdiagnosis, , prognosisprognosis, , therapy including therapy including dosage of medicationsdosage of medications, , riskrisk//benefitbenefit andand costcost--effectivenesseffectiveness. . Then they define the most important questions related to Then they define the most important questions related to clinical practice and identify all possibleclinical practice and identify all possible decision optionsdecision options and theirand their outcomesoutcomes. . Some guidelines contain decision or Some guidelines contain decision or computationcomputation algorithmsalgorithms to be followedto be followed. . Thus, they Thus, they integrate the identified decision points and respective integrate the identified decision points and respective courses of action to the clinical judgment and experience courses of action to the clinical judgment and experience of practitionersof practitioners. . Many guidelines place the treatment Many guidelines place the treatment alternatives into classes to help providers in deciding alternatives into classes to help providers in deciding which treatment to usewhich treatment to use..

Qualification of evidenceQualification of evidence

Evidence-based medicine categorizes different Evidence-based medicine categorizes different types of clinical evidence and ranks them types of clinical evidence and ranks them according to the strength of their freedom from the according to the strength of their freedom from the various biases that beset medical research. various biases that beset medical research.

Systems to stratify evidence by quality have been Systems to stratify evidence by quality have been developed, such as this one by the U.S. developed, such as this one by the U.S. Preventive Services Task Force for ranking Preventive Services Task Force for ranking evidence I,II.III and the UK National Health Service evidence I,II.III and the UK National Health Service uses a similar system with categories labeled A, B, uses a similar system with categories labeled A, B, C, and D. C, and D.

TheThe UU..SS. . Preventive Services Task ForcePreventive Services Task Force for ranking evidence about for ranking evidence about the effectiveness of treatments or screeningthe effectiveness of treatments or screening::

Level ILevel I: : Evidence obtained from at least one properly Evidence obtained from at least one properly designeddesigned randomized controlled trialrandomized controlled trial. .

Level II-1Level II-1: : Evidence obtained from wellEvidence obtained from well--designed designed controlled trials withoutcontrolled trials without randomizationrandomization. .

Level II-2Level II-2: : Evidence obtained from wellEvidence obtained from well--designeddesigned cohortcohort oror casecase--controlcontrol analytic studies, preferably from more analytic studies, preferably from more than one center or research groupthan one center or research group. .

Level II-3Level II-3: : Evidence obtained from multiple time series Evidence obtained from multiple time series with or without the interventionwith or without the intervention. . Dramatic results in Dramatic results in uncontrolled trials might also be regarded as this type of uncontrolled trials might also be regarded as this type of evidenceevidence. .

Level IIILevel III: : Opinions of respected authorities, based on Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of clinical experience, descriptive studies, or reports of expert committeesexpert committees

The above Levels are only appropriate for treatment or The above Levels are only appropriate for treatment or interventions interventions

Different types of research are required for Different types of research are required for assessing diagnostic accuracy or natural assessing diagnostic accuracy or natural history and prognosis, and hence different history and prognosis, and hence different ""levelslevels" " are requiredare required. . For example, the Oxford For example, the Oxford Centre for EvidenceCentre for Evidence--based Medicine suggests based Medicine suggests levels of evidence levels of evidence ((LOELOE) ) according to the study according to the study designs and critical appraisal of prevention, designs and critical appraisal of prevention, diagnosis, prognosis, therapy, and harm diagnosis, prognosis, therapy, and harm studiesstudies::

Level ALevel A: : ConsistentConsistent Randomized Controlled Randomized Controlled Clinical TrialClinical Trial, , cohort studycohort study, , all or none , clinical all or none , clinical decision rule validated in different populationsdecision rule validated in different populations. .

Level BLevel B: : Consistent Retrospective Cohort, Consistent Retrospective Cohort, Exploratory Cohort, Ecological Study, Outcomes Exploratory Cohort, Ecological Study, Outcomes ResearchResearch, , casecase--control studycontrol study; ; or extrapolations or extrapolations from level A studiesfrom level A studies. .

Level CLevel C: : CaseCase--series studyseries study or extrapolations or extrapolations from level B studiesfrom level B studies. .

Level DLevel D: : Expert opinion without explicit critical Expert opinion without explicit critical appraisal, or based onappraisal, or based on physiologyphysiology, , bench bench research or first principlesresearch or first principles. .

Categories of recommendationsCategories of recommendations

In guidelines and other publications, In guidelines and other publications, recommendation for a clinical service is recommendation for a clinical service is classified by the balance of risk versus classified by the balance of risk versus benefit of the service benefit of the service andand the level of the level of evidence on which this information is based.evidence on which this information is based.

The U.S. Preventive Services Task Force The U.S. Preventive Services Task Force uses the followinguses the following::

Level ALevel A: : Good scientific evidence suggests that the Good scientific evidence suggests that the benefits of the clinical service substantially benefits of the clinical service substantially outweighs the potential risksoutweighs the potential risks. . Clinicians should Clinicians should discuss the service with eligible patientsdiscuss the service with eligible patients. .

Level BLevel B: : At least fair scientific evidence suggests At least fair scientific evidence suggests that the benefits of the clinical service outweighs the that the benefits of the clinical service outweighs the potential riskspotential risks. . Clinicians should discuss the service Clinicians should discuss the service with eligible patientswith eligible patients. .

Level CLevel C: : At least fair scientific evidence suggests At least fair scientific evidence suggests that there are benefits provided by the clinical that there are benefits provided by the clinical service, but the balance between benefits and risks service, but the balance between benefits and risks are too close for making general recommendationsare too close for making general recommendations. . Clinicians need not offer it unless there are individual Clinicians need not offer it unless there are individual considerationsconsiderations. .

Level DLevel D: : At least fair scientific evidence At least fair scientific evidence suggests that the risks of the clinical suggests that the risks of the clinical service outweighs potential benefitsservice outweighs potential benefits. . Clinicians should not routinely offer the Clinicians should not routinely offer the service to asymptomatic patientsservice to asymptomatic patients. .

Level ILevel I: : Scientific evidence is lacking, of Scientific evidence is lacking, of poor quality, or conflicting, such that the poor quality, or conflicting, such that the risk versus benefit balance cannot be risk versus benefit balance cannot be assessedassessed. . Clinicians should help patients Clinicians should help patients understand the uncertainty surrounding understand the uncertainty surrounding the clinical servicethe clinical service. .

Quality of clinical trial publicationsQuality of clinical trial publications

EvidenceEvidence--based medicine attempts to based medicine attempts to objectively evaluate the quality of clinical objectively evaluate the quality of clinical research by critically assessing techniques research by critically assessing techniques reported by researchers in their reported by researchers in their publicationspublications..

Trial design considerationsTrial design considerations. . HighHigh--quality studies quality studies have clearlyhave clearly--defined eligibility criteria, and have defined eligibility criteria, and have minimal missing dataminimal missing data. .

Generalizability considerationsGeneralizability considerations. . Studies may only Studies may only be applicable to narrowlybe applicable to narrowly--defined patient defined patient populations, and may not be generalizable to populations, and may not be generalizable to clinical practiceclinical practice. .

FollowupFollowup. . Sufficient time for defined outcomes to Sufficient time for defined outcomes to occur can influence the study outcomes and theoccur can influence the study outcomes and the statistical powerstatistical power of a study to detect differences of a study to detect differences between a treatment and control armbetween a treatment and control arm. .

PowerPower. . A mathematical calculation can determine A mathematical calculation can determine if the number of patients is sufficient to detect a if the number of patients is sufficient to detect a difference between treatment armsdifference between treatment arms. . A negative A negative study may reflect a lack of benefit, or simply a study may reflect a lack of benefit, or simply a lack of sufficient quantities of patients to detect a lack of sufficient quantities of patients to detect a differencedifference. .

Practice of EvidencePractice of Evidence-- based basedMedicineMedicine

The practice of EBM is through asking a The practice of EBM is through asking a good clinical question by which is an good clinical question by which is an answerable question that will limit your answerable question that will limit your findingsfindings. . A good clinical question contains 4 A good clinical question contains 4 parts or the PICO question; iparts or the PICO question; i..ee..

Population, patient and problemPopulation, patient and problem Intervention, prognostic factor, or exposureIntervention, prognostic factor, or exposure ComparisonComparison OutcomeOutcome

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