高血压英文ppt精品课件univariate

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1、UnivariateAnalysisandTable1MarkDrazner,MD,MScUniversityofTexasSouthwesternMedicalCenterJune11,2004RiskFactorOutcomeExposureExplanatoryvariableIndependentvariableDependentvariableResponseDiseaseTypesofVariablesinYourExperimentObjectiveIstheriskfactorassociated

2、withtheoutcome?Isthereapattern?ValidityandGeneralizabilityInternalValidityIfindapattern,isitreal(reproducible)?ChanceBiasConfoundingExternalValidityDoesitapplytootherpatients?GeneralizabilityToolsAgainstInvalidityChance:StatisticsBias:Studydesign(Wasitafairst

3、udy?)Confounding:MultivariableanalysisStatisticalAnalysesUnivariate1RiskFactor1OutcomeMultivariableMultipleriskfactors1OutcomeWhichStatisticalTestDoIUse?ItdependsontypeofdatabeinganalyzedTypesofdatainclinicalresearchCategorical:Nominalvs.OrdinalDichotomous>2c

4、ategoriesContinuousSurvivalPaireddataLimitedtypesofdatameanslimitednumberofstatisticaltestsHypertensionConcentricLVHDilatedCardiomyopathyParadigmofHypertensiveHeartDisease“TransitiontoFailure”Rameet.al,AJC,2004RetrospectiveStudy:ParklandEchocardiographyDatab

5、ase(1992–1994)LowEFNormalEFn=28n=131(18%)(82%)159subjectsConcentricLVH(>1.3cm)NormalLVEFFollow-upecho.≥1yearlater4yearf/uRame,AJC,2004SomePurposesofTable1ProvidebaselinecharacteristicsWhatpatientswerestudied?Aretheyapplicabletothereader’spatients(generalizab

6、ility)?Isthestudybelievable–e.g.,authorssaytheystudiedadvancedheartfailure,dopatientshavecharacteristicsofadvancedheartfailure?Whataredifferencesatbaselinebetween2groups(e.g.,case-control)?Randomizedclinicaltrial:Didrandomizationwork?HowDidWeMakeTable1?Method

7、sSection“Dataareexpressedasproportions,means±SD,ormedians(25thand75thpercentiles).DifferencesincharacteristicsbetweenpatientswhodidordidnotprogresstoadepressedEFwerecomparedbyFisher’sexacttest,Student’sttestwithequalorunequalvariances,orWilcoxonrank-sumtest,w

8、hereappropriate.”Rame,AJC,2004WhatTypeofDataareYouAnalyzing?DichotomousOutcomeEitherOrDichotomousRiskFactorsEpidemiologistsLove2x2TablesDisease/OutcomeRiskFactor/Exposure+-+-StatisticalT