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Evaluate bias in meta-analysis within meta-epidemiological studies - Pubrica

In some meta epidemiological studies, the effect of interventions in RCTu2019s (Randomised Controlled Trials) can be misunderstood leading to underestimation or overestimation of the intervention.<br><br>Continue Reading: https://bit.ly/3hligkZ<br>For our services: https://pubrica.com/services/research-services/meta-analysis/<br>

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Evaluate bias in meta-analysis within meta-epidemiological studies - Pubrica

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  1. HOWTOEVALUATEBIASIN META-ANALYSISWITHIN META-EPIDEMIOLOGICAL STUDIES? AnAcademicpresentationby Dr.NancyAgnes,Head,TechnicalOperations,Pubrica Group:www.pubrica.com Email:sales@pubrica.com

  2. TODAY'SDISCUSSION Outline Introduction Biasinmeta-analysiswithin meta-epidemiologicalstudies Conclusion

  3. INTRODUCTION Meta-analysisisatypeofstatisticalapproach whichsynthesizesresultsfromdifferent studiesandthefinalresultservesasamuch strongerevidencethantheonecollected fromanindividualstudy. Itgivesanestimateofthesuccessofanewly introducedtreatment/interventionortherisk factorsassociatedwithadisease/lineof treatment(Haydenetal.,2021). Thus,itcanserveasthebestsourcefor evidence-basedclinicalstudies. Contd...

  4. Thestudiesusedinmeta-analysiscancombineresultsfromsystematic review,randomisedcontrolledtrials(RCT)etc. Metaepidemiologicalstudiesisanewtypeofmethodwhichhelpsin closingthegapbetweentrialsandpracticeandisamuchimproved versionofsystematicreview(Page,2020). Theyadopteithersystematicreviewormeta-analysisapproachandaims tounderstandtheimpactofcertainfactorsontheoutcome. Thus,theytrytoconfirmornullifythehypothesisinquestion. Theobjectofanalysisisastudyandnotapatientoranindividual. Contd...

  5. Resultsofmeta-epidemiologicalstudymightbedirectlyrelatedtoexposurebutResultsofmeta-epidemiologicalstudymightbedirectlyrelatedtoexposurebut canalsobearesultofanalternativeeffectthatmighthaveimpactedtheoverall studyoutcome. Thesealternativeeffectscanbearandomerror,abiasthatcanproduce incorrectresults(Steenlandetal.,2020). Duetotheseeffects,sometimesanassociationisfalselyaccountedforinthe outcomewhenitisnotpresentandontheotherhand,sometimesanassociation isoverlookedeveninitspresence.

  6. BIASINMETA-ANALYSISWITHIN META-EPIDEMIOLOGICALSTUDIES Insomemetaepidemiologicalstudies,theeffectof interventionsinRCT’s(RandomisedControlled Trials)canbemisunderstoodleadingto underestimationoroverestimationoftheintervention (ChristensenandBerthelsen,2020). Therecanbeseveralreasonswhichhavebeen elaboratedbellow- Biasarisingduetorandomisation-Theprocedureof sequencegenerationorallocationconcealmentmight varytheeffectsoftheintroducedinterventions. Contd...

  7. Thesetwofactorsalsoaffectstheinbetweenheterogeneity. Biasarisingduetooptingforunintendedinterventions-Thistypeofbiasarises whentheparticipantoptsforaninterventiondifferentfromwhichtheyhavebeen randomlyallottedfor. Biasarisingduetolackofproperoutcomedata-Theexaggerationofthe interventioneffectcanarisewhenthedataofoutcomesareeithernotcompletely/ falselyreported. Therearesomeexampleswhenthereisoverestimationandunderestimationofthe interventioneffectevenwhentheoutcomehasbeenproperlyrecorded. Contd...

  8. Thisiscausedduetoattrition,buttheaveragebiasreportedduetoattritionThisiscausedduetoattrition,buttheaveragebiasreportedduetoattrition couldnotbecombinedasthedefinitionofattritiondiffersacrossstudies. Biasarisingduetoimproperresultselection-Therehasbeenreportsof biaswhentheoutcomesarenotproperlygeneratedduetodiscrepancies betweenresultsandmethods. Biasarisingduetoincorrectlymeasuringoutcomes-Duetolackofproper outcomeaccessors,biasarisesinproperlymeasuringtheoutcomes. Thisresultsinimproperestimationofinterventioneffects. Contd...

  9. Inmostmeta-epidemiologicalstudies,awritten protocolforselectingthestudiesneedtobeframed beforeconductingthemetaanalysis. Itisimportanttoincludealltherelatedstudiesas missingoutononecanintroducebiasandmakesthe studylesseffective(Panetal.,2020). Theprotocolmustfocusontheselectioncriteria (eligibilitycriteria,typeofstudiestobeincluded,etc.) ofthestudiestoreducesectionbias.Fig1depictsa flowchartofselectingstudies. Contd...

  10. Fig1:Flowchartforselectionofstudies

  11. Alongsidethese,theotherimportantpointstobe includedintheprotocolareobjectivesofthestudy, hypothesistobetestedetc(Steenlandetal.,2020). Accordingtosomeauthors,itcanbequitetrickyto combinedifferentstudydesignsofmeta- epidemiologicalstudiesinameta-analysisandthus havestated“ameta-analysismaygiveaprecise estimateofaveragebias,ratherthananestimateof theintervention’seffect”andthat“heterogeneity betweenstudyresultsmayreflectdifferentialbiases ratherthantruedifferencesinanintervention’seffect”. Contd...

  12. Inordertounderstandtheamountofbiasthatmighthaveimpactedthe studyoutcome,ithasbeenunanimouslyagreeduponthatallthenon- randomizedandobservationalstudiesincludedinthemeta-analysisshould beassessed(Puljaketal.,2020). Buttherehasbeennoproperagreementontheguidelinesofassessingthe riskofbiasindifferentmeta-analyses(MathurandVanderWeele,2021). Metaepidemiologicalstudieshelpsinovercomingthechallengesof systematicreviews. Outofall,itfocusestogetridofpublicationbias. Contd...

  13. Publicationbiasisalsoanimportanttypeofbiasthat stressesuponthefactthatthedatausedinmeta- epidemiologicalstudiesshouldalsobedrawnupon fromunpublishedstudysources(Lin,2020). Itissometimesobservedthatfewstudiesarenot acceptedforpublishingastheyreportnegative results. Thus,missingoutonthesecanenhancetheriskof biasandcangiveafalseimpressionaboutthe effectivenessoftheinterpretation(Tanetal.,2021).

  14. CONCLUSION Thebiaswhicharisesduringdifferentstepsofthe meta-analysismustbeaddressedasthismightreport contradictoryresults. Itmustbenotedthatfalsereportscanimpactmedical researchwhichcanbefatalinfewaspects. Theproblemwithmeta-epidemiologicalstudyliesin thefactthatwhenthenumberofstudiesreduces,the statisticalpoweralsoreduces.

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