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IntroductiontoEvidenceBasedMedicine

ChaisiriAngkurawaranonDepartmentofFamilyMedicine

Outline

1.Introduction:whatisEBM2.Thestepsinevidencebasedpractice3.Anexample4.Reflectionandfurtherinformation

Question:Whichisit?AorB

AThedoctor istheretogivethepatients alltheinformationthatthepatientneedsinorderthatthepatient canmakeadecision,andthedoctorshouldthenimplementthatdecisiononcethepatient hasmadeit

BThepatient istheretogivethedoctor alltheinformationthatthedoctorneedsinorderthatthedoctor canmakeadecision,andthepatientshouldthenimplementthatdecisiononcethedoctor hasmadeit

Wewillcomebackattheendofclass

WhyEBM

• A21st centuryclinicalwhocannotcriticallyreadastudyisasunpreparedasonewhocannottakeabloodpressureorexaminethecardiovascularsystem

Evidencebasedmedicineandthemedicalcurriculum.BMJ2008:337:704-705

EvidenceBasedMedicine EBM

EBMis"theconscientious,explicitandjudicioususeofcurrentbestevidenceinmakingdecisionsaboutthecareoftheindividualpatient.Itmeansintegratingindividualclinicalexpertisewiththebestavailableexternalclinicalevidencefromsystematicresearch."(Sackett D,1996)

Thebasicskillsofusing(notdoing)research–searching,appraisingandapplyingtoindividualpatients

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EBM

• EBMistheintegrationofclinicalexpertise,patientvalues,andthebestevidenceinto thedecisionmakingprocessforpatientcare.

• Clinicalexpertisereferstotheclinician'scumulatedexperience,educationandclinicalskills.

• The patientbringstotheencounterhisorherownpersonalanduniqueconcerns,expectations,andvalues.

• Thebestevidenceisusuallyfoundinclinicallyrelevantresearchthathasbeenconductedusingsoundmethodology.(Sackett D,2002)

Example1

• Apatientcometotheclinicwithfreshdogbite• Itlooksclean• Itisnecessarytogiveprophylacticantibiotics

Yes

No

Example1

• Ametaanalysisindicatedthattheaverageinfectionratefordogbiteswas14%andthatantibioticshalvedtherisk

• Wouldyougiveprophylacticantibiotic

CummingsP(1994)Antibioticstopreventinfectioninpatientswithdogbitewounds:Ameta-analysisofrandomizedcontroltrials.AnnalsofEmergencyMedicine23:533-40

Whatskillsareneededforacliniciantotoapplysuchevidence?

2.StepsinEBM

• 2.1Formulateananswerablequestion--ASK• 2.2Trackdownthebestevidenceofoutcomesavailable-- ACQUIRE

• 2.3criticallyappraisetheevidence(howgoodandwhatitmeans)– APPRAISE

• 2.4applytheevidence-- APPLY• Results+clinicalexpertise+patientvalues

• 2.5Assessoutcome- ASSESS

Exercise

• Insmallgroups:• Writedownsomeclinicalquestionsorproblemsthatyouthinkadoctormayface

• Don’tthinktoohard• Canuseyourownexperienceorfamilyexperience

http://www.mathgoodies.com/calculators/random_no_custom.html

CommonTypesofclinicalQuestion

Question Questiontype

WhatshouldIdoaboutthis conditionorproblem Intervention

Whatisthecause oftheproblem Aetiology andriskfactors

Doesthisperson havetheconditionorproblem? Diagnosis

Whowillgettheconditionorproblem Prognosticandprediction

Howcommonisthe problem Frequencyandrate

Whatarethetypes ofproblems Phenomenaorthoughts

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Backgroundquestions

• Asked for general knowledge about a disorder• Has two essentials components:

• a question root ( who, what, where, how, why) with a verb

• a disorder

Backgroundquestions

• WhatarethesymptomsandsignsofsomeonepresentingwithMI?

• WhatarethediagnosistestsforMI?• WhatarethecausesofMI?• WhatarethetreatmentsforMI• Textbooks answer background questions, they

contain collected & synthesized wisdom for topics that do not change often.

Clinicalquestions(Foregroundquestions)◆Knowyourbackground◆Askedforspecific knowledgeaboutmanagingpatientswithadisorder

◆Ithas4components(PICO analysis):P - Patient/PopulationI- InterventionC- ComparisonO - Outcome

Step ins EBM

1.Formulate an answerable question - ASK

PICOPrinciple Description

Population Therelevent peopleinrelationtotheclinicalproblem

Intervention(orindicatororindextest)

Intervention, exposureortestthatyouwanttofindoutaboutinrelationtotheclinicalproblem

Comparator Thealternative, controlstrategy,exposureortestforcomparisonwiththeoneyouareinterestedint

Outcome Whatyouoryourpatientisconcernedabouthappening (ornothappening)

PICO Example

You ask your patient, a long term smoker, if he is interested in smokingHe said he has tried unsuccessfully in the pastHis friend successfully quit with acupuncture, should he try?The interventions you are used to are nicotine replacement therapy and antidepressantsPICOPrinciple DescriptionPopulation Longtermsmoker

Intervention(orindicatororindextest)

Acupuncture

Comparator Placebo ornicotinereplacementorantidepressant

Outcome Quitsmoking(at3-6months?

Theclinicalquestion:Doesacupuncture,comparedwithotherinterventions,improvethechanceofquittingsmokinginlongtermsmokers?

PICO Example

Your friend wants to discuss with you the possibility of getting a vasectomyHe heard that vasectomy can cause testicular cancer in later lifeAlthough you know that the risk is low, he wants to know the precise answer

PICOPrinciple DescriptionPopulation Adultmales

Intervention(orindicatororindextest)

vasectomy

Comparator Novasectomy

Outcome Testicularcancer

Theclinicalquestion:Doesvasectomyincreasetheriskofgettingtesticularcancerinthefuture?

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PICO Example

A baby was born premature at 35 weeks. Her parents ask about her chances of developing deafness

PICOPrinciple DescriptionPopulation Prematurebaby

Intervention(orindicatororindextest)Comparator

Outcome deafness

Theclinicalquestion:Ininfantsbornprematurely,whatisthefrequency(prev)ofdeafness?

YourOwnQuestion

PICOPrinciple Description

Population

Intervention(orindicatororindextest)

Comparator

Outcome

Step2:trackingdownthebestevidence(ACQUIRE)

OCEBM(Oxfordcentre forEBM)"TheOxford2011LevelsofEvidence".

Trackingthebestevidence(intervention)DoesthisinterventionhelpStep1(Level1) Systematicreviewofrandomized trials

orn-of-1trialsStep 2(Level2) RCT orobservationalstudywith

dramaticeffectStep 3(Level3) Non-randomizedcontrolled

cohort/follow upstudyStep4 (level4) Case-series, casecontrolstudiesor

historicallycontrolledstudiesStep5(level5) Mechanism-basedreasoning

Ahierarchyofthe LIKELYbestevidence,

Levelofevidence

• Doesnotgiveadefinitivejudgmentaboutthequalityofevidence.‘Lowerlevel’evidencecanstillprovidestrongerevidencethana‘higherlevel’study(examplevegetableconsumptionandpancreaticcancer– cohortvs systematicreview)

• WILLNOTPROVIDEYOUWITHARECOMMNATION,evenifthetreatmentaresupportedbybestevidence– mustconsider

• Patientissimilartostudy• Clinicalbenefitoutweighsharms?• Isanothertreatmentbetter• Arepatient’svaluesandcircumstancescompatiblewithtreatment

• LevelscanNOTtellyouwhetheryouareaskingtherightquestions.Ifyouinterpretmeningitisastheflu,findingbesttreatmentforfluwillnothelp

2.ChoosingresourcesSubject advantages Disadvantages

Pubmed ormedline Biomedicineandclinicalmedicine.Veterinarymedicine.

FreeGoodN.AmericancoverageLinkstosomefull-text

OnlycoversjournalarticlesNorthAmericanbias

EMBASE/OVID Biomedicineandclinicalmedicine.Veterinarymedicine.

VerygoodforpharmaceuticalinformationGoodEuropeancoverage

OnlycoversjournalarticlesEuropeanbias

CochraneLibrary Clinicalinterventionsonly‘Goldstandard’systematicreviews

FulltextsystematicreviewsFreeinmanycountries

Informationoninterventionsonly

Webofscience Science,socialsciences,arts&humanitiesGeneralcoverageofmostacademicdisciplines.

Cansearchreferencelistsandseewhohascitedarticlesofinterest.Containsdetailsofcitationrates,H-indexandotherstatistics

Notasin-depthasthemoresubjectspecificresources.Nosubjectheadings/thesaurussearchingavailable.Interfacedoesnotcopewithverylong,complexsearchstrategies

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ChoosingResources

• Googledoesnotsearcheverywebsiteintheworld.Thisoftenincludesthecontentsofbibliographicdatabases.

• WhenGoogledoesasearch,itdoesnotsearchtheliveinternet.Itsearchesacopythatcanbesixmonthsoutofdate,meaningyoumissthemostrecentinformation.

• Googleisabusiness.Thismeansthattheresultsonthefirstpagearenotalwaysthebestqualityorthemostrelevant.

Searchingtips:Pubmed

BOOLEANSinCAPITALS• OR:example-- childORadolescent• AND:examplechildANDadolescent• NEAR:wordsmustbewithin5wordsofeachother.NotavailableinpubmedbutinMEDLINE

• NOT:excludesstudiescontainingwords• ():useparenthesestogroupwordsexample• *Truncation:exampleinjur*=injury,injuriesinjured• “”:searchthephrase

Combiningyoursearchstrategy

• (concept1synonymORconcept1synonymORconcept1synonym)AND(concept2synonymORconcept2synonymORconcept2synonym)AND(concept3synonymORconcept3synonymORconcept3synonym)

Combiningyoursearchstrategy

• (dengueORaedes ORflavivirus)AND(weatherORclimate*ORtemperature*ORrain*ORseason*)AND(SouthAmericaORColombiaORVenezuelaORGuyanaORSurinameORFrenchGuianaOREcuadorORPeruORBrazilORBoliviaORParaguayORChileORArgentinaORUruguay)

Candenguefeveroutbreaksinsouthamericabepredictedbytheweather

ClinicalQueriesusingResearchMethodologyFilters(PUBMED)• ClinicalQueries• rabiesANDprophylaxisANDantibiotics

http://www.ncbi.nlm.nih.gov/pubmed/clinical

Summarysofar

1.Introduction:whatisEBM2.Thestepsinevidencebasedpractice• Ask• Acquire• Appraise• Apply• Assess3.Someexamples4.Reflectionandfurtherinformation

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Break? Appraise

• HowgoodtheyareforANSWERINGyourclinicalquestion

Threeoverallquestions• WhatisthePICOofthestudy,andisitcloseenoughtoyourPICO?

• Howwellwasthestudydone?• Internalvalidity(thequalityofstudy,methods,preventionofbiasandconfounding)

• Whatdotheresultsmean?RR?,ARR?,NNT?RRR?Clinicalvs statisticalsignificance,chance?

ToolsWorksheet

• CEBMprovidescriticalappraisalworksheetsfor• Systematicreview• Diagnosticresearch• Prognosis

http://www.cebm.net/resources/cebm-presentations/medical-student-resources/

Exampleworksheet

• RCT

Step4:Applytheevidence

• Ask• Acquire• Appraise• Apply• Assess

Applyevidence

Ask• Isthetreatmentortestfeasibleinmysetting

• Isitavailable• Canyouprovidenecessarymonitoringandfollowup• Willpatientbeabletocomplywiththetreatmentorregimen

• Whatalternativesareavailable• Ismypatientsodifferentthattheresultsdoesnotapply

• Potentialbenefitsvs potentialharms• WHATDOESMYPATIENTTHINKABOUTIT

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IncorporatePatientvaluesSimplecommunicationprocess• Explainwhatwouldhappenwedidnothing• Explainwhattheoptionsare(feasibility,risk,benefit)

• Checkthepatient’sexpectationsandideas

StepsinEBM

5.Assess• Followupthepatientandassessmentofoutcomesafterimplicationoftreatment

Outline

1.Introduction:whatisEBM2.Thestepsinevidencebasedpractice(5A’s)3.Someexamples4.Reflectionandfurtherinformation

Example

• Mr.ShaspoorlymanageTypeIIdiabetesandaskiftakingcinnamonwouldimproveherfastingbloodglucose

• Task1:Asking-- DefinePICO• Task2:Acquire--definesimplesearchterms

Searching Thestudy

• LeachMJ,KumarS.Cinnamonfordiabetesmellitus.CochraneDatabase ofSystematicReviews2012,Issue9

• Thisarticlesystematicallyreviewedpapersinvestigatingwhethercinnamonaffecteddiabeticmanagement,usingfastingbloodglucoseasitsprimaryoutcome.

• Thepaper’srecentpublicationsuggeststhatthelatestevidencecollectedwillhavebeenincludedintheirreview.

• ThemeanagerangeofparticipantsintrialsreviewedincludedthatofMissS.

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AppraisalTheauthors’search: 14searchengineswereusedtofindrelevantpapers,including:• – TheCochraneLibrary(issue12,2011).– MEDLINE(untilJanuary2012).– EMBASE(untilJanuary2012).

Selection:– 2reportersindependentlyscannedtheabstractofeverypaperretrievedbythe searchtoensureinclusioncriteriaweremet:• Randomised controlledtrials• Orallyadministeredmonopreparations ofcinnamon• Placebo/activemedication/notreatment.• TypeIorIIdiabetes– Potentiallimitation–onlypaperspublishedinEnglishwereselected.Pertinentreportspublishedinotherlanguagesmayhavebeenmissed.

Appraisal

RANDOMISATION• 10 prospective, parallel-group design, randomised control trials, involving a

total of 577 participants with either Type 1 or 2 diabetes were included. • 1 of the 10 studies didn’t use a placebo control.• 6 studies were double-blinded, 2 single-blinded and 2 undefined with respect

to blinding. – However, the precise blinding protocol was not clearly described in many trials

included in the review. ALLOCATION• Gender was approximately distributed evenly in most trials.• The mean age of participants ranged from 52-63 years.• Bias was assessed independently by two reviewers using a pre-defined criteria

(Higgins, 2008).• Risk of bias was

high or unclear in 8/10 trials, with the remaining 2 assessed as having a moderate risk.

Leach MJ, Kumar S., 2012.

Appraisal

MAINTENANCE – All studies used oral monopreparation of cinnamon in tablet or capsule

form.– 3 studies were excluded after careful evaluation of the full publication –

primarily due to failure to meet the diagnostic criteria for Type 1 or 2 diabetes.

– Where possible, any relevant missing information on the trial was sought from the original author(s) of the article – e.g. reasons for drop-outs were inconsistently reported.

MEASUREMENT – Heterogeneity was assessed by visual inspection of the forest plots and

by using a standard Chi2 test:• Cinnamon vs. Placebo; Outcome – fasting blood glucose level

(mmol/L) Chi2=0.97. – If one of the primary outcome parameters showed significant

differences between the intervention groups subgroup analysis was performed:• Cinnamon species• Cinnamon dosage• Treatment duration• Type of diabetes (I or II)

Results

The Results (interpretation of findings)• There were 8 studies reporting data on fasting blood glucose for 388 participants.

• These showed significant heterogeneity (Chi2=0.82).• Visual inspection of the funnel plot and subgroup analysis led the authors to

exclude 2 out of these 8 studies as outliers. • Analysis of the 6 remaining studies found no statistically significant

difference in fasting blood glucose between cinnamon and placebo groups (P=0.55 ; 95%CI -0.34 to 0.18).

• Adverse effects were recorded in 4 trials.– 3 events in intervention groups:

• Rash• Hives• Hypoglycaemic episode

– 4 events in control groups. • Nausea• Stomach ache• Other frequent illness

– Overall, there was no significant difference between adverse effects in the intervention and control group.

Implications

• Apply– whatwouldyousay

Outline

1.Introduction:whatisEBM2.Thestepsinevidencebasedpractice(5A’s)3.Anexample4.SelfReflectionandfinalthoughts

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SelfReflection

Nextyearask• Areyouaskinganyquestionsatall?• Whatisyoursuccessrateinaskinganswerablequestions

• Howisyoursearchinggoing?--- stillGOOGLE?/Wikepedia/Pantip?

• Areyoucriticallyappraisingyoursearchresults• Areyouapplyingevidenceinclinicalpractice

EBM

• Helpyoumakeclinicaldecision• Sharedecisionwithpatients• Providebetterdiagnosticreasoning• Understandbenefitsversusharms• Allowyoutopracticemoresafely

FinalThoughts

• Widevariationsinimplementationofevidencebasedpractice

CrisisinEBM• Theevidencebased‘qualitymark’hasbeenmisappropriatedbyvestedinterests(drugandmedicaldeviceindustries)

• Toomuchevidence(toomanyguidelines)• Marginalgainsandashiftfromdiseasetorisk• Overemphasisonfollowingalgorithmicrules• Poorfitformultimorbidity

RealconceptofEBM

• Makestheethicalcareofthepatientitstoppriority• Demandsindividualizedevidenceinaformatthatcliniciansandpatientscanunderstand

• Characterizedbyexpertjudgmentratherthanmechanicalrulefollowing

• Sharesdecisionswithpatientsthroughmeaningfulconversation

• Buildsonstrongdoctor-patientrelationshipandthehumanaspectsofcare

• Appliestheseprinciplesatcommunitylevelforevidencebasedpublichealth

FinalQuestion:Whichisit?AorB

AThedoctor istheretogivethepatients alltheinformationthatthepatientneedsinorderthatthepatient canmakeadecision,andthedoctorshouldthenimplementthatdecisiononcethepatient hasmadeit

BThepatient istheretogivethedoctor alltheinformationthatthedoctorneedsinorderthatthedoctor canmakeadecision,andthepatientshouldthenimplementthatdecisiononcethedoctor hasmadeit

Questions