joint modeling longitudinal data and survival data

《joint modeling longitudinal data and survival data》由会员上传分享，免费在线阅读，更多相关内容在工程资料-天天文库。

1、CHAPTER8JointModelingLongitudinalDataandSurvivalData8.1IntroductionAsshowninChapter7,survivaldataoftenariseinlongitudinalstudies.Inprac-tice,wemayneedtomodelatime-to-eventprocessandalongitudinalprocessjointly.Acommonsituationisinsurvivalmodelswithtime-dependentcovari-ates,inwhichcovariatedatamaybemi

2、ssingatfailuretimes,soalongitudinalmodelforthecovariatesisrequiredtoaddressmissingcovariatesorcovariatemeasurementerrors.Asanotherexample,inmodelinglongitudinaldatawithdropouts,wemayalsoneedtomodelthetimestodropoutortimestodeath,withtheobjectivesofavoidingpossiblebiasesintheestimationofthelongi-tudi

3、nalmodel,aswellasstudyingtheassociationbetweenthetimetoeventandcharacteristicsofthelongitudinaltrajectoriessuchasinitialslopesorin-tercepts.Inbothcases,jointmodelingofthelongitudinaldataandthesurvivaldataisrequired.Injointmodelingoflongitudinaldataandsurvivaldata,themainfocusmaybeeitherthelongitudin

4、almodel,orthesurvivalmodel,orbothmodels,dependingontheobjectivesofthestudies.Whenthemainfocusisononemodel,theothermodelisthensecondarysoitsparametersmaybeviewedasnuisanceparameters.Inthiscase,oneshouldfocusoncorrectspecicationofthemainmodelandsimplifythesecondarymodeltoreducethenumberofnuisancepara

5、metersandavoidpotentialparameternon-identiability.Ifbothmodelsareofprimaryinterest,wemayreducethenumberofothersecondaryparameterssuchastheassociationparameters.Injointmodelingoflongitudinaldataandsurvivaldata,weoftenhavethefollowingthreesituations:themainfocusisonmodelingsurvivaldata,withmodelingl

6、ongitudinaldatabeingsecondary.Thissituationmayarise,forexample,insurvival253254MIXEDEFFECTSMODELSFORCOMPLEXDATAmodelswithmeasurementerrorsormissingdataintime-dependentcovari-ates,wheremodelingthelongitudinalcovariateprocessesisonlyusedtoaddressmeasurementerrorsormissingdata(covariatedatamaybemissing

7、atfailuretimes);themainfocusisonmodelinglongitudinaldata,withmodelingsurvivaldatabeingsecondary.Thissituationmayarise,forexample,intheanalysisoflongitudinaldatawithinformativedropouts,whereasurvivalm