Treatment
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1 CLINICAL DECISION USING AN ARTICLE ABOUT TREATMENT George G. Lim, MD, FPSGS, FPCS, FPSCRS Professor I, Department of Surgery UST Faculty of Medicine & Surgery Principles of Decision Making Knowing the paEent’s true state is oGen unnecessary Treatment error is always a possibility when the diagnosis is uncertain The need for diagnosEc certainty depends on the penalty for being wrong Decision Making in Medicine The main issue is making choices Diagnosis o Should I request for a laboratory examinaEon or treat right away? o Between two diagnosEc alternaEves, which one should I request? Treatment o Should I start treatment or observe first? o Between two or more drugs, which one should I prescribe? Decision Making in the Old Paradigm Pathophysiologic understanding Common sense Experience Experts Medical Evidence Decision Making in the New Paradigm Medical Evidence Pathophysiologic understanding Common sense Experience Experts A 72‐year old female consulted you for hypertension and elevated cholesterol. During your discussion on cardiac risks, she inquires about the need to take an anE‐cholesterol drug. What advise will you give? The PaDent
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Critical Appraisal
Transcript of Treatment
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CLINICALDECISIONUSINGANARTICLEABOUT
TREATMENT
GeorgeG.Lim,MD,FPSGS,FPCS,FPSCRSProfessorI,DepartmentofSurgery
USTFacultyofMedicine&Surgery
PrinciplesofDecisionMaking
KnowingthepaEentstruestateisoGenunnecessary
Treatmenterrorisalwaysapossibilitywhenthediagnosisisuncertain
TheneedfordiagnosEccertaintydependsonthepenaltyforbeingwrong
DecisionMakinginMedicine
Themainissueismakingchoices Diagnosis
oShouldIrequestforalaboratoryexaminaEonortreatrightaway?
oBetweentwodiagnosEcalternaEves,whichoneshouldIrequest?
TreatmentoShouldIstarttreatmentorobserverst?oBetweentwoormoredrugs,whichoneshouldIprescribe?
DecisionMakingintheOldParadigm
Pathophysiologicunderstanding Commonsense Experience Experts MedicalEvidence
DecisionMakingintheNewParadigm
MedicalEvidence Pathophysiologicunderstanding Commonsense Experience Experts
A72yearoldfemaleconsultedyouforhypertensionandelevatedcholesterol.Duringyourdiscussiononcardiacrisks,sheinquiresabouttheneedtotakeananEcholesteroldrug.
Whatadvisewillyougive?
ThePaDent
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DecisionMakingintheOldParadigm
Pathophysiologyo Hypercholesterolemiapromotescoronaryarterydiseasethuscholesterol
isariskfactor
Commonsenseo Loweringcholesterolalsolowerstheriskofcoronaryarterydisease
Experienceo IfcholesteroliselevatedbylaboratoryexaminaEon,itcanbeloweredby
drugs
Expertso NaEonalCholesterolEducaEonProgram:screenalladultpaEentsand
intervenewhennecessary
DecisionMakingintheNewParadigm
FormulatetheproblemintoananswerablequesEon
ConductasystemaEcmedicalliteraturesearch CriEcallyappraisethemedicalliterature Applytheresults EvaluatetheapplicaEon
TheEBMPracDDoner
EBMPracEEoneroAmongelderlypaEentswhohaveelevatedcholesterol,willanEcholesteroldrugsbebenecial?
ThesearchoMEDLINEoRandomizedtrialofcholesterolloweringin4444paEentswithcoronaryheartdisease:theScandinavianSimvastaEnSurvivalStudy
CaseControlStudies
AdvantagesoQuickandcheapoOnlyfeasiblemethodforveryraredisordersorthosewithlonglagbetweenexposureandoutcome
oFewersubjectsneededthancrosssecEonalstudies
CaseControlStudies
DisadvantagesoRelianceonrecallorrecordstodetermineexposurestatus
oConfoundersoSelecEonofcontrolgroupsisdicultoPotenEalbias:recall,selecEon
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CrossSecDonalSurvey
AdvantagesoCheapandsimpleoEthicallysafe
DisadvantagesoEstablishesassociaEonatmost,notcausalityoRecallbiassuscepEbilityoConfoundersmaybeunequallydistributedoNeymanbiasoGroupsizesmaybeunequal
CohortStudy
AdvantagesoEthicallysafeoSubjectscanbematchedoCanestablishEminganddirecEonalityofeventsoEligibilitycriteriaandoutcomeassessmentscanbestandardized
oAdministraEvelyeasierandcheaperthanRCT
CohortStudy
DisadvantagesoThecontrolsmaybediculttoidenEfyoExposuremaybelinkedtoahiddenconfounderoBlindingisdicultoRandomizaEonnotpresentoForraredisease,largesamplesizesorlongfollowupnecessary
CrossoverDesign
AdvantagesoAllsubjectsserveasowncontrolsanderrorvarianceisreducedthusreducingsamplesizeneeded
oAllsubjectsreceivetreatment(atleastsomeoftheEme)
oStaEsEcaltestsassumingrandomizaEoncanbeusedoBlindingcanbemaintained
CrossoverDesign
DisadvantagesoAllsubjectsreceiveplacebooralternaEvetreatmentatsomepoint
oWashoutperiodlengthyorunknownoCannotbeusedfortreatmentswithpermanenteects
RandomizedControlledTrial
AdvantagesoUnbiaseddistribuEonofconfoundersoBlindingmorelikelyoRandomizaEonfacilitatesstaEsEcalanalysis
DisadvantagesoExpensive:EmeandmoneyoVolunteerbiasoEthicallyproblemaEcatEmes
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RandomizedControlledTrial
ProvidetheBESTevidenceofeecEveness Individualsarerandomlyassigned(randomizaEon)toeitherofthegroups
RandomizaEontriestomakethegroupsSIMILAR
TheyareobservedFORWARDinEmeandtheiroutcomescompared
Theoutcomecanbethecureofadisease,reliefofsymptoms,orimprovementinqualityoflife
Relevance
IstheobjecEveofthearEclecomparingintervenEonssimilartoyourclinicaldilemma?oPopulaEonofthestudy(P)shouldbesimilartothecharacterisEcofyourpaEent
o IntervenEon/comparaEveintervenEon/exposure(I)shouldincludethetherapeuEcintervenEonyouwanttotest
oOutcomeofthestudy(O)oneoftheoutcomesmeasuredshouldbethegoalyouandyourpaEentwishtoworkfor
Relevance
IstheobjecEveofthearEclecomparingintervenEonssimilartoyourclinicaldilemma?oYES
TheobjecEveofthestudyistocompareSimvastaEn,ananEcholesteroldrugwithplacebo
EBMonTherapy
Validityo IsthearEclelikelytobetrue?
ImportanceoHowlargeisthesizeoftheeect?
ApplicabilityoWillthendingsworkinmypaEent?
AretheResultsValid?
WastheassignmentofpaEentstotreatmentsrandomized?oYES
TheEtle,abstractandthemethodologysecEonstatedthatthestudywasadoubleblindrandomizedcontrolledtrial
AretheResultsValid?
WereallpaEentswhoenteredthetrialproperlyaccountedforandagributedatitsconclusion?oWasfollowupcomplete?oWerepaEentsanalyzedinthegroupstowhichtheywererandomized?
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Dropouts
ControlDropoutRate
TreatmentDropoutRate
ControlDeathRate
TreatmentDeathRate
A.1% 1% 20% 10%
B.1% 1% 2% 1%
C.10% 10% 50% 10%
D.10% 10% 10% 5%
E.1% 10% 5% 5%
AretheResultsValid?
WereallpaEentswhoenteredthetrialproperlyaccountedforandagributedatitsconclusion?oYES
4,444paEentswererandomizedandanalyzedaccordingtointenEontotreatprinciple.
IntheTableforthemainanalysis,thesumofpaEentsineachgrouptotaled4,444,thenumberwhowererandomized
IntenDontoTreatPrinciple
Subjects Treatment FailureA
1000(0)
6months 100/1000=10%
1000(100)
1year 45/900=5%
IntenDontoTreatPrinciple
Subjects Treatment FailureA FailureB
1000(0)
6months 100/1000=10%
100/1000=10%
1000(100)
1year 45/900=5%
135/1000=13.5%
AretheResultsValid?
WerepaEents,healthworkersandstudypersonnelblindtotreatment?oYES
Thestudywasadoubleblindcontrolledtrial
AretheResultsValid?
Werethegroupssimilaratthestartoftreatment?oYES
Table1oftheresultssecEonshowednomajordierenceinthebaselinecharacterisEcsbetweenthetwogroups
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AretheResultsValid?
AsidefromexperimentalintervenEon,werethegroupstreatedequally?oYES
TherewerenoplannedcointervenEonforthetwogroups
WhataretheResults?
Ifyouweighed80kgaGertheChristmasholidays,and60kgaGerasummerdiet,whatwouldbethewaysofexpressingyourweightloss?o Ilost20kg(absoluteweightreducEon)o Iamnow75%ofwhatIusedtoweigh(relaEveweight)
o Ilost25%ofmyweight(relaEveweightreducEon)
WhataretheResults?
Measures Formula Figures
RiskinControl(Rc) DeathControl/NControl 256/2222=11.5%
RiskinTreatment(Rt)DeathTreatment/NTreatment
182/2222=8.2%
AbsoluteRiskReducEon(ARR)
RcRt11.58.2%=3.3%or
0.03
RelaEveRisk(RR) Rt/Rc 0.082/0.115=0.71
RelaEveRiskReducEon(RRR)
1RR 10.71=0.29or29%
NumberNeededtoTreat(NNT)
1/ARR 1/0.03=33.3
WhataretheResults?
Measures Figures
RiskinControl(Rc) 256/2222=11.5%
RiskinTreatment(Rt) 182/2222=8.2%
AbsoluteRiskReducEon(ARR)
11.58.2%=3.3%or0.03
Deathispreventedin3%ofpaEentstakingthedrug
RelaEveRisk(RR) 0.082/0.115=0.71Theriskofdeathisnow71%ofwhatitusedtobe
RelaEveRiskReducEon(RRR)
10.71=0.2929%reducEonindeathwhentakingdrugcomparedtotakingplacebo
NumberNeededtoTreat(NNT)
1/0.03=33.3Youwillhavetotreat33paEentstoprevent1death
WhataretheResults?
HowprecisewastheesEmateofthetreatmenteect?oRRofdeathintheSimvastaEngroup=0.71o95%CI0.580.85,p=0.0003
CantheresultshelpmeincaringformypaDent?
CantheresultsbeappliedtomypaEentcare?oYES
SubjectsincludedinthisstudywerepaEentswithanginaorMIandelevatedcholesterol
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CantheresultshelpmeincaringformypaDent?
Wereallclinicallyimportantoutcomesconsidered?oYES
ThemainoutcomesconsideredwerenewonsetofMI,coronarydeath,andoverallcauseofdeath
CantheresultshelpmeincaringformypaDent?
ArethelikelytreatmentbenetsworththepotenEalharmandcost?o33paEentstoprevent1death(orsave1life)[email protected]
At365days=P18,250For33paEents=P602,250For5years=P3M
o72yearoldpaEent
CantheresultshelpmeincaringformypaDent?
AreyourpaEentsvaluesandpreferencessaEsedbytheregimenanditsconsequences?oDoyourpaEentandyouhaveaclearassessmentoftheirvaluesandpreferences?
oAretheymetbythisregimenanditsconsequences?
A72yearoldfemaleconsultedyouforhypertensionandelevatedcholesterol.Duringyourdiscussiononcardiacrisks,sheinquiresabouttheneedtotakeananEcholesteroldrug.
Whatadvisewillyougive?
Iwouldrathernotgiveanan1cholesteroldrug.Thebenetistoosmallforthecostitwilltake.
Whatadvicewillyougiveyour72yearoldpaDent?
A72yearoldfemaleconsultedyouforhypertensionandelevatedcholesterol.Duringyourdiscussiononcardiacrisks,sheinquiresabouttheneedtotakeananEcholesteroldrug.
Whatadvisewillyougive?
Iwillprescribeanan1cholesteroldrug.Mypa1entcanaordthecostevenifthebenetisnotlarge.
Whatadvicewillyougiveyour72yearoldpaDent?
KeepASKING
KeepSEARCHING
KeepLEARNING
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Thankyou.
