Risk Factors for All-Cause Hospital Readmission Within 30 Days of Hospital Discharge

Objective:�Todevelopapredictivemodelof�30-day� readmissionusingclinicalandadministrativedata. •� Design:� Retrospectivecohortstudy.� Afterdividing� dataintodevelopmentalandvalidationsets,�multivari- ablelogisticregressionwasperformed. •� Participants:�AdultswithdatainHealthFacts,�adata- basecomposedofparticipatinghospitals'� electronic� medicalrecords.� Theindexhospitalizationwasa� patient'sfirstqualifyinghospitaladmissionbetween� 1� October� 2008� and� 31� August� 2010.�Weexcluded� observationstays,�admissionswithlengthofstayof�0� days,�obstetricstays,�andpatientswhosepredominant� caresettingwasapsychiatricorrehabilitationunit. •� Measurements:�Readmissionwithin�30�daysoflive� dischargefromtheindexhospitalization. •� Results:�Therewere�463,351�indexadmissionsto�91� hospitals,�with�45,098�(9.7%)�patientsreadmitted.�In� multivariablemodeling,�factorsassociatedwithread- missionincludedpriorhospitaladmission,�lowhemo- globin,�longerstays,�andincreasingCharlsonindex;� arthroplastyprocedureswereassociatedwithlower� riskofreadmission.�Modeldiscriminationwasmodest� indevelopmentaldata�(c-statistic�=�0.668)�andslightly� lower�(0.657)�invalidationdata. •� Conclusions:�Increasedcomorbidityandpriorhospital� exposureareassociatedwithunplannedreadmission.� Despitetheavailabilityofmanypotentiallyrelevant� clinicalvariables,� modelperformancewasmodest� andfewclinicalvariableswereassociatedwithread- missioninamultivariablemodel.�Focusingonspecific� conditionswithanarrowersetofrelevantvariables� mayfacilitateidentifyingpatientsatparticularlyhigh� riskforreadmission.