2023
Excess Mortality and Years of Potential Life Lost Among the Black Population in the US, 1999-2020
Caraballo C, Massey D, Ndumele C, Haywood T, Kaleem S, King T, Liu Y, Lu Y, Nunez-Smith M, Taylor H, Watson K, Herrin J, Yancy C, Faust J, Krumholz H. Excess Mortality and Years of Potential Life Lost Among the Black Population in the US, 1999-2020. JAMA 2023, 329: 1662-1670. PMID: 37191702, PMCID: PMC10189563, DOI: 10.1001/jama.2023.7022.Peer-Reviewed Original ResearchConceptsExcess mortality ratesExcess deathsMortality ratePotential lifeWhite populationExcess mortalitySerial cross-sectional studyHighest excess mortality ratesBlack populationCause-specific mortalityCross-sectional studyHigh mortality rateNon-Hispanic whitesYears of lifeUS national dataMiddle-aged adultsCause mortalityHeart diseaseDeath certificatesNon-Hispanic black populationMAIN OUTCOMEAge groupsDisease controlMortalityBlack males
2022
Proceedings From a National Heart, Lung, and Blood Institute and the Centers for Disease Control and Prevention Workshop to Control Hypertension
Commodore-Mensah Y, Loustalot F, Himmelfarb CD, Desvigne-Nickens P, Sachdev V, Bibbins-Domingo K, Clauser SB, Cohen DJ, Egan BM, Fendrick AM, Ferdinand KC, Goodman C, Graham GN, Jaffe MG, Krumholz HM, Levy PD, Mays GP, McNellis R, Muntner P, Ogedegbe G, Milani RV, Polgreen LA, Reisman L, Sanchez EJ, Sperling LS, Wall HK, Whitten L, Wright JT, Wright JS, Fine LJ. Proceedings From a National Heart, Lung, and Blood Institute and the Centers for Disease Control and Prevention Workshop to Control Hypertension. American Journal Of Hypertension 2022, 35: 232-243. PMID: 35259237, PMCID: PMC8903890, DOI: 10.1093/ajh/hpab182.Peer-Reviewed Original ResearchConceptsHypertension controlBlood pressureHypertension treatmentBlood InstituteNational HeartSelf-measured BP monitoringDisease controlCommunity-clinical linkagesModifiable risk factorsMore cardiovascular eventsAge-adjusted proportionSurgeon General's CallTeam-based careHigh-quality health carePublic health messagingCardiovascular eventsStroke preventionControl hypertensionBP monitoringHeart diseaseRisk factorsUS adultsClinical supportHealth messagingSocial determinants
2021
Characteristics, interventions and outcomes of patients with valvular heart disease hospitalised in China: a cross-sectional study
Huang X, Dhruva SS, Yuan X, Bai X, Lu Y, Yan X, Liu J, Li W, Hu D, Ji R, Gao M, Miao F, Li J, Ge J, Krumholz HM, Li J. Characteristics, interventions and outcomes of patients with valvular heart disease hospitalised in China: a cross-sectional study. BMJ Open 2021, 11: e052946. PMID: 34732492, PMCID: PMC8572400, DOI: 10.1136/bmjopen-2021-052946.Peer-Reviewed Original ResearchConceptsSevere valvular heart diseaseValvular heart diseaseHigh operative riskRheumatic originValve interventionHospital outcomesOperative riskCommon etiologyPrimary diagnosisHeart diseaseSeverity of VHDTypes of VHDCommon valvular heart diseaseMultivariable logistic regression analysisDegenerative valvular heart diseaseOutcomes of patientsCross-sectional studyLogistic regression analysisTwo-stage random sampling designClinical characteristicsFrequent etiologyPredominant etiologyTricuspid regurgitationAdult patientsPatient characteristics
2020
Secondary prevention of cardiovascular disease in China
Lu J, Zhang L, Lu Y, Su M, Li X, Liu J, Zhang H, Nasir K, Masoudi F, Krumholz H, Li J, Zheng X. Secondary prevention of cardiovascular disease in China. Heart 2020, 106: 1349-1356. PMID: 31980439, DOI: 10.1136/heartjnl-2019-315884.Peer-Reviewed Original ResearchMeSH KeywordsAdultAge FactorsAgedAlcohol DrinkingCardiovascular DiseasesChinaFemaleHealthy LifestyleHeart Disease Risk FactorsHumansHydroxymethylglutaryl-CoA Reductase InhibitorsMaleMiddle AgedPlatelet Aggregation InhibitorsRisk AssessmentRisk Reduction BehaviorSecondary PreventionSex FactorsSmoking CessationTime FactorsTreatment OutcomeConceptsSecondary prevention drugsIschemic heart diseaseCardiovascular diseasePrevention drugsIschemic strokeSecondary preventionAntiplatelet drugsCardiac Events Million Persons ProjectHistory of IHDMillion Persons ProjectSecondary prevention therapiesPopulation subgroupsMultivariable mixed modelsPublic health programsCommunities of ChinaCurrent smokersCurrent useMedication usePrevention therapyMultivariable analysisChina PatientHeart diseaseCurrent drinkersHealth programsDrugs
2019
Interplay of Coronary Artery Calcium and Risk Factors for Predicting CVD/CHD Mortality The CAC Consortium
Grandhi GR, Mirbolouk M, Dardari ZA, Al-Mallah MH, Rumberger JA, Shaw LJ, Blankstein R, Miedema MD, Berman DS, Budoff MJ, Krumholz HM, Blaha MJ, Nasir K. Interplay of Coronary Artery Calcium and Risk Factors for Predicting CVD/CHD Mortality The CAC Consortium. JACC Cardiovascular Imaging 2019, 13: 1175-1186. PMID: 31734198, DOI: 10.1016/j.jcmg.2019.08.024.Peer-Reviewed Original ResearchMeSH KeywordsAdultAgedCause of DeathComputed Tomography AngiographyCoronary AngiographyCoronary Artery DiseaseDiabetes MellitusDyslipidemiasFemaleHeart Disease Risk FactorsHumansHypertensionMaleMiddle AgedMultidetector Computed TomographyPredictive Value of TestsPrevalencePrognosisRetrospective StudiesRisk AssessmentSmokingTime FactorsUnited StatesVascular CalcificationConceptsCoronary artery calciumCoronary heart diseaseRisk factorsCause-specific mortalityRF burdenCause mortalityArtery calciumCAC scoreCVD mortalityAbsence of CACHigher CAC scoresCHD mortality ratesCurrent cigarette smokingCardiovascular disease deathsCAC ConsortiumCAC testingMulticenter cohortCigarette smokingDisease deathsHeart diseasePrognostic informationBaseline riskFamily historyMost deathsMortality rateP573Effects of mobile text messaging on glycemic control in patients with coronary heart disease and diabetes mellitus: a randomized controlled trial
Huo X, Krumholz H, Bai X, Spatz E, Ding Q, Horak P, Zhao W, Gong Q, Yan X, Wu X, Li J, Li X, Spertus J, Masoudi F, Zheng X. P573Effects of mobile text messaging on glycemic control in patients with coronary heart disease and diabetes mellitus: a randomized controlled trial. European Heart Journal 2019, 40: ehz747.0184. DOI: 10.1093/eurheartj/ehz747.0184.Peer-Reviewed Original ResearchCoronary heart diseaseIntervention groupPhysical activityControl groupGlycemic controlHeart diseaseBaseline 6 monthsHigh-risk patientsText messaging programsSecondary outcome analysisMobile health interventionsText message programMean change differenceBP controlGlycemic hemoglobinHbA1c levelsLifestyle modificationUsual careDiabetes mellitusFamily Planning CommissionPrimary outcomeLifestyle recommendationsMonth followRisk factorsClinical trialsEffects of Mobile Text Messaging on Glycemic Control in Patients With Coronary Heart Disease and Diabetes Mellitus
Huo X, Krumholz HM, Bai X, Spatz ES, Ding Q, Horak P, Zhao W, Gong Q, Zhang H, Yan X, Sun Y, Liu J, Wu X, Guan W, Wang X, Li J, Li X, Spertus JA, Masoudi FA, Zheng X. Effects of Mobile Text Messaging on Glycemic Control in Patients With Coronary Heart Disease and Diabetes Mellitus. Circulation Cardiovascular Quality And Outcomes 2019, 12: e005805. PMID: 31474119, DOI: 10.1161/circoutcomes.119.005805.Peer-Reviewed Original ResearchMeSH KeywordsAgedAsian PeopleBiomarkersBlood GlucoseChinaCoronary DiseaseCulturally Competent CareDiabetes MellitusExerciseFemaleGlycated HemoglobinHealth CommunicationHealthy LifestyleHumansHypoglycemic AgentsMaleMedication AdherenceMiddle AgedMotivationPatient Education as TopicRisk Reduction BehaviorSelf CareSingle-Blind MethodTelemedicineText MessagingTime FactorsTreatment OutcomeConceptsCoronary heart diseaseHeart diseaseGlycemic controlIntervention groupUsual careDiabetes mellitusBlood glucosePhysical activityControl groupText message-based interventionBlood pressure controlProportion of patientsRisk factor managementGood glycemic controlSystolic blood pressureBody mass indexText messaging programsText message interventionMobile health interventionsSecondary outcomesBlood pressurePrimary outcomeLDL cholesterolMass indexMedication adherenceEffect of Text Messaging on Risk Factor Management in Patients With Coronary Heart Disease
Zheng X, Spatz ES, Bai X, Huo X, Ding Q, Horak P, Wu X, Guan W, Chow CK, Yan X, Sun Y, Wang X, Zhang H, Liu J, Li J, Li X, Spertus JA, Masoudi FA, Krumholz HM. Effect of Text Messaging on Risk Factor Management in Patients With Coronary Heart Disease. Circulation Cardiovascular Quality And Outcomes 2019, 12: e005616. PMID: 30998400, DOI: 10.1161/circoutcomes.119.005616.Peer-Reviewed Original ResearchMeSH KeywordsAgedAsian PeopleBlood PressureChinaCoronary DiseaseCulturally Competent CareFemaleHealth Knowledge, Attitudes, PracticeHumansMaleMiddle AgedPatient Education as TopicRisk AssessmentRisk FactorsSecondary PreventionSingle-Blind MethodTelemedicineText MessagingTime FactorsTreatment OutcomeConceptsCoronary heart diseaseSystolic blood pressureBody mass indexBlood pressureHeart diseaseSecondary preventionIntervention groupPhysical activityEnd pointSmoking statusMass indexControl groupPrimary end pointRisk factor controlSecondary end pointsRisk factor managementLDL-C levelsDisease-specific knowledgeMobile phone textMobile health technologyUsual careDiabetes mellitusMedication adherenceRisk factorsFactor management
2018
Risk Factors Associated With Major Cardiovascular Events 1 Year After Acute Myocardial Infarction
Wang Y, Li J, Zheng X, Jiang Z, Hu S, Wadhera RK, Bai X, Lu J, Wang Q, Li Y, Wu C, Xing C, Normand SL, Krumholz HM, Jiang L. Risk Factors Associated With Major Cardiovascular Events 1 Year After Acute Myocardial Infarction. JAMA Network Open 2018, 1: e181079-e181079. PMID: 30646102, PMCID: PMC6324290, DOI: 10.1001/jamanetworkopen.2018.1079.Peer-Reviewed Original ResearchConceptsAcute myocardial infarctionMajor cardiovascular eventsCardiovascular eventsRisk factorsC-statisticMyocardial infarctionAggressive risk factor reductionOne-year event ratesSubsequent major cardiovascular eventsRecurrent acute myocardial infarctionIndex AMI hospitalizationRisk factor reductionHigh-risk patientsProspective cohort studyCoronary heart diseaseLow-risk groupAcute care hospitalsCohort studyCommon comorbiditiesHeart failureMean ageRisk modelHeart diseaseMAIN OUTCOMEHigh riskSex Differences in the Presentation and Perception of Symptoms Among Young Patients With Myocardial Infarction
Lichtman JH, Leifheit EC, Safdar B, Bao H, Krumholz HM, Lorenze NP, Daneshvar M, Spertus JA, D'Onofrio G. Sex Differences in the Presentation and Perception of Symptoms Among Young Patients With Myocardial Infarction. Circulation 2018, 137: 781-790. PMID: 29459463, PMCID: PMC5822747, DOI: 10.1161/circulationaha.117.031650.Peer-Reviewed Original ResearchConceptsAcute myocardial infarctionPerception of symptomsChest painCare-seeking behaviorSymptom presentationYounger patientsMyocardial infarctionST-segment elevation acute myocardial infarctionMultivariable hierarchical logistic regressionIndex AMI hospitalizationMajority of womenHierarchical logistic regressionStress/anxietyVIRGO StudyMuscle painPatient characteristicsPredominant symptomAMI symptomsPerceive symptomsProdromal symptomsPatient interviewsHeart diseasePainAMI hospitalizationUS hospitals
2016
Acute Myocardial Infarction in Women
Mehta LS, Beckie TM, DeVon HA, Grines CL, Krumholz HM, Johnson MN, Lindley KJ, Vaccarino V, Wang TY, Watson KE, Wenger NK. Acute Myocardial Infarction in Women. Circulation 2016, 133: 916-947. PMID: 26811316, DOI: 10.1161/cir.0000000000000351.Peer-Reviewed Original ResearchConceptsAcute myocardial infarctionMyocardial infarctionMortality rateFirst scientific statementOutcomes of womenCardiovascular disease mortalityCardiovascular disease riskCardiovascular disease mortality ratesCoronary heart diseaseAmerican Heart AssociationDisease mortality ratesEvidence-based treatmentsCause of mortalityClinical presentationPathophysiological mechanismsHeart AssociationDisease mortalityHeart diseaseCardiovascular diseaseSex-specific differencesCurrent evidenceInfarctionDisease riskWomenScientific statement
2015
Qingdao Port Cardiovascular Health Study: a prospective cohort study
Spatz ES, Jiang X, Lu J, Masoudi FA, Spertus JA, Wang Y, Li X, Downing NS, Nasir K, Du X, Li J, Krumholz HM, Liu X, Jiang L. Qingdao Port Cardiovascular Health Study: a prospective cohort study. BMJ Open 2015, 5: e008403. PMID: 26656011, PMCID: PMC4679897, DOI: 10.1136/bmjopen-2015-008403.Peer-Reviewed Original ResearchMeSH KeywordsAdultAgedAsian PeopleBody Mass IndexCardiovascular DiseasesChinaCohort StudiesCost of IllnessDiabetes Mellitus, Type 2Early DiagnosisEnvironmental ExposureFemaleHealth BehaviorHealth SurveysHumansHyperlipidemiasHypertensionIncidenceMaleMiddle AgedOccupational ExposurePhysical ExaminationPreventive Health ServicesProspective StudiesRisk FactorsSelf ReportSocioeconomic FactorsWorkplaceConceptsAnnual health assessmentCardiovascular diseaseRisk factorsUnique risk factor profileCardiovascular risk factorsClinical risk factorsProspective cohort studyRisk factor profileHospital medical recordsCardiovascular Health StudyPopulation-based studyPopulation-based strategiesHealth assessmentCardiovascular outcomesCohort studyCarotid ultrasoundMean agePhysical examinationCardiovascular healthHeart diseaseMedical recordsDisease onsetMedical insurance claimsHealth StudyUrine analysisSex Differences in Cardiac Risk Factors, Perceived Risk, and Health Care Provider Discussion of Risk and Risk Modification Among Young Patients With Acute Myocardial Infarction The VIRGO Study
Leifheit-Limson EC, D’Onofrio G, Daneshvar M, Geda M, Bueno H, Spertus JA, Krumholz HM, Lichtman JH. Sex Differences in Cardiac Risk Factors, Perceived Risk, and Health Care Provider Discussion of Risk and Risk Modification Among Young Patients With Acute Myocardial Infarction The VIRGO Study. Journal Of The American College Of Cardiology 2015, 66: 1949-1957. PMID: 26515996, PMCID: PMC4628727, DOI: 10.1016/j.jacc.2015.08.859.Peer-Reviewed Original ResearchConceptsCardiac risk factorsAcute myocardial infarctionHealth care provider discussionsRisk modificationRisk factorsHeart diseaseHealth care providersProvider discussionsVIRGO StudyYounger patientsMyocardial infarctionCare providersSignificant cardiac risk factorsYoung AMI patientsPatients age 18Heart disease riskRisk factor prevalenceSelf-perceived riskModified Poisson regressionSex differencesFactor prevalenceAMI patientsCardiac riskSpanish hospitalsProvider feedbackSymptom Recognition and Healthcare Experiences of Young Women With Acute Myocardial Infarction
Lichtman JH, Leifheit-Limson EC, Watanabe E, Allen NB, Garavalia B, Garavalia LS, Spertus JA, Krumholz HM, Curry LA. Symptom Recognition and Healthcare Experiences of Young Women With Acute Myocardial Infarction. Circulation Cardiovascular Quality And Outcomes 2015, 8: s31-s38. PMID: 25714826, PMCID: PMC4801001, DOI: 10.1161/circoutcomes.114.001612.Peer-Reviewed Original ResearchMeSH KeywordsAdultAge FactorsConflict, PsychologicalFemaleHealth Knowledge, Attitudes, PracticeHealth Status DisparitiesHealthcare DisparitiesHospitalizationHumansInterviews as TopicMiddle AgedMyocardial InfarctionPatient Acceptance of Health CarePreventive Health ServicesQualitative ResearchRecognition, PsychologyRisk AssessmentRisk FactorsSex FactorsTime FactorsTime-to-TreatmentConceptsAcute myocardial infarctionCare-seeking behaviorAcute careMyocardial infarctionProdromal symptomsHeart diseaseSymptom recognitionAcute myocardial infarction symptomsAcute myocardial infarction mortalityHealthcare systemMyocardial infarction symptomsPreventive health careCare-seeking experiencesMyocardial infarction mortalityAcute medical therapyPreventive health behaviorsCardiovascular riskMedical therapyPrompt recognitionPreventive carePrimary careInfarction symptomsAged menMortality riskHealth behaviors
2012
2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients With Stable Ischemic Heart Disease
Fihn SD, Gardin JM, Abrams J, Berra K, Blankenship JC, Dallas AP, Douglas PS, Foody JM, Gerber TC, Hinderliter AL, King SB, Kligfield PD, Krumholz HM, Kwong RY, Lim MJ, Linderbaum JA, Mack MJ, Munger MA, Prager RL, Sabik JF, Shaw LJ, Sikkema JD, Smith CR, Smith SC, Spertus JA, Williams SV. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients With Stable Ischemic Heart Disease. Circulation 2012, 126: 3097-3137. PMID: 23166210, DOI: 10.1161/cir.0b013e3182776f83.Peer-Reviewed Original Research2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients With Stable Ischemic Heart Disease
Fihn SD, Gardin JM, Abrams J, Berra K, Blankenship JC, Dallas AP, Douglas PS, Foody JM, Gerber TC, Hinderliter AL, King SB, Kligfield PD, Krumholz HM, Kwong RY, Lim MJ, Linderbaum JA, Mack MJ, Munger MA, Prager RL, Sabik JF, Shaw LJ, Sikkema JD, Smith CR, Smith SC, Spertus JA, Williams SV, Anderson JL. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients With Stable Ischemic Heart Disease. Circulation 2012, 126: e354-e471. PMID: 23166211, DOI: 10.1161/cir.0b013e318277d6a0.Peer-Reviewed Original Research2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients With Stable Ischemic Heart Disease: Executive Summary A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons
Fihn SD, Gardin JM, Abrams J, Berra K, Blankenship JC, Dallas AP, Douglas PS, Foody JM, Gerber TC, Hinderliter AL, King SB, Kligfield PD, Krumholz HM, Kwong RY, Lim MJ, Linderbaum JA, Mack MJ, Munger MA, Prager RL, Sabik JF, Shaw LJ, Sikkema JD, Smith CR, Smith SC, Spertus JA, Williams SV. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients With Stable Ischemic Heart Disease: Executive Summary A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Journal Of The American College Of Cardiology 2012, 60: 2564-2603. PMID: 23182124, DOI: 10.1016/j.jacc.2012.07.012.Peer-Reviewed Original ResearchAmerican CollegeAmerican Heart Association Task ForcePreventive Cardiovascular Nurses AssociationStable ischemic heart diseaseCardiology Foundation/American Heart Association Task ForceIschemic heart diseaseManagement of patientsThoracic surgeryHeart diseasePractice guidelinesCardiovascular AngiographyThoracic surgeonsSTS guidelinesA ReportNurses AssociationAmerican AssociationTask ForceAssociationGuidelinesPatientsSurgeryAngiographyDiseaseDiagnosisPhysiciansDiscontinuation of Antihyperglycemic Therapy After Acute Myocardial Infarction: Medical Necessity or Medical Error?
Lovig KO, Horwitz L, Lipska K, Kosiborod M, Krumholz HM, Inzucchi SE. Discontinuation of Antihyperglycemic Therapy After Acute Myocardial Infarction: Medical Necessity or Medical Error? The Joint Commission Journal On Quality And Patient Safety 2012, 38: 403-407. PMID: 23002492, PMCID: PMC3534988, DOI: 10.1016/s1553-7250(12)38051-3.Peer-Reviewed Original ResearchConceptsAcute myocardial infarctionLeft ventricular ejection fractionAntihyperglycemic therapyDiabetic patientsMyocardial infarctionMedical necessityOne-year mortalityDetailed chart reviewVentricular ejection fractionIschemic heart diseaseNational Medicare databaseMedical errorsAcademic medical centerQuality improvement opportunitiesChart reviewClinical characteristicsOlder patientsRecurrent hypoglycemiaEjection fractionMedicare databaseBlood glucoseHeart diseasePrincipal diagnosisCommunity hospitalMedical Center
2011
30-Day Readmission for Patients Undergoing Percutaneous Coronary Interventions in New York State
Hannan EL, Zhong Y, Krumholz H, Walford G, Holmes DR, Stamato NJ, Jacobs AK, Venditti FJ, Sharma S, King SB. 30-Day Readmission for Patients Undergoing Percutaneous Coronary Interventions in New York State. JACC Cardiovascular Interventions 2011, 4: 1335-1342. PMID: 22192374, DOI: 10.1016/j.jcin.2011.08.013.Peer-Reviewed Original ResearchConceptsPercutaneous coronary interventionReadmission ratesUnique risk factorsRisk factorsCoronary interventionAdministrative databasesComplications of PCIPre-procedural risk factorsRepeat percutaneous coronary interventionChronic ischemic heart diseaseOverall readmission rateHigher readmission ratesIschemic heart diseaseLength of stayNew York State patientsRecognition of patientsDiagnostic risk factorsCost-effectiveness standpointPCI patientsPCI registryChest painHeart failureHospital readmissionHeart diseasePrincipal diagnosisNational and Regional Trends in Heart Failure Hospitalization and Mortality Rates for Medicare Beneficiaries, 1998-2008
Chen J, Normand SL, Wang Y, Krumholz HM. National and Regional Trends in Heart Failure Hospitalization and Mortality Rates for Medicare Beneficiaries, 1998-2008. JAMA 2011, 306: 1669-1678. PMID: 22009099, PMCID: PMC3688069, DOI: 10.1001/jama.2011.1474.Peer-Reviewed Original ResearchConceptsHF hospitalization ratesHeart failure hospitalizationHospitalization ratesMortality rateFailure hospitalizationHeart failure hospitalization ratesPrincipal discharge diagnosis codeOne-year mortality rateDischarge diagnosis codesIschemic heart diseaseAcute care hospitalsService Medicare beneficiariesLower ratesBlack menHF hospitalizationPatient demographicsCare hospitalDiagnosis codesHeart diseaseRisk factorsMedicare beneficiariesHospitalizationStudy periodMortalityNational mean