Featured Publications
Clinical characteristics and outcomes for 7,995 patients with SARS-CoV-2 infection
McPadden J, Warner F, Young HP, Hurley NC, Pulk RA, Singh A, Durant TJS, Gong G, Desai N, Haimovich A, Taylor RA, Gunel M, Dela Cruz CS, Farhadian SF, Siner J, Villanueva M, Churchwell K, Hsiao A, Torre CJ, Velazquez EJ, Herbst RS, Iwasaki A, Ko AI, Mortazavi BJ, Krumholz HM, Schulz WL. Clinical characteristics and outcomes for 7,995 patients with SARS-CoV-2 infection. PLOS ONE 2021, 16: e0243291. PMID: 33788846, PMCID: PMC8011821, DOI: 10.1371/journal.pone.0243291.Peer-Reviewed Original ResearchConceptsSARS-CoV-2 infectionYale New Haven HealthSARS-CoV-2Hospital mortalityRisk of admissionMale sexRisk factorsSARS-CoV-2 testingInvasive mechanical ventilationSevere acute respiratory syndrome virusBurden of diseaseRT-PCR testingAcademic health systemDiverse patient populationsRespiratory syndrome virusEthnic groupsAdult patientsClinical characteristicsDischarge dispositionRespiratory supportPrimary outcomeTreatment guidelinesMechanical ventilationRetrospective studyPatient population
2024
Use of electronic health records to characterize patients with uncontrolled hypertension in two large health system networks
Lu Y, Keeley E, Barrette E, Cooper-DeHoff R, Dhruva S, Gaffney J, Gamble G, Handke B, Huang C, Krumholz H, McDonough C, Schulz W, Shaw K, Smith M, Woodard J, Young P, Ervin K, Ross J. Use of electronic health records to characterize patients with uncontrolled hypertension in two large health system networks. BMC Cardiovascular Disorders 2024, 24: 497. PMID: 39289597, PMCID: PMC11409735, DOI: 10.1186/s12872-024-04161-x.Peer-Reviewed Original ResearchConceptsElectronic health recordsHealth recordsHealth systemUncontrolled hypertensionUse of electronic health recordsHypertension managementElectronic health record systemsOneFlorida Clinical Research ConsortiumElectronic health record dataYale New Haven Health SystemBP measurementsICD-10-CM codesHealth system networkPublic health priorityICD-10-CMIncidence rate of deathElevated BP measurementsElevated blood pressure measurementsHealthcare visitsAmbulatory careHealth priorityRetrospective cohort studyEHR dataOneFloridaBlood pressure measurementsGenome-wide association study between SARS-CoV-2 single nucleotide polymorphisms and virus copies during infections
Li K, Chaguza C, Stamp J, Chew Y, Chen N, Ferguson D, Pandya S, Kerantzas N, Schulz W, Initiative Y, Hahn A, Ogbunugafor C, Pitzer V, Crawford L, Weinberger D, Grubaugh N. Genome-wide association study between SARS-CoV-2 single nucleotide polymorphisms and virus copies during infections. PLOS Computational Biology 2024, 20: e1012469. PMID: 39288189, PMCID: PMC11432881, DOI: 10.1371/journal.pcbi.1012469.Peer-Reviewed Original ResearchConceptsGenome-wide association studiesSingle-nucleotide polymorphismsAssociation studiesWhole-genome sequencingAmino acid changesSingle nucleotide polymorphismsPairs of substitutionsViral copiesEpistasis testsGenome sequenceGenetic variationSpike geneAcid changesViral genomeNucleotide polymorphismsSARS-CoV-2Detect interactionsHost factorsVirus copiesCopyInfection dynamicsRT-qPCRPolymorphismOmicron BASARS-CoV-2 infectionHigh burden of viruses and bacterial pathobionts drives heightened nasal innate immunity in children
Watkins T, Green A, Amat J, Cheemarla N, Hänsel K, Lozano R, Dudgeon S, Germain G, Landry M, Schulz W, Foxman E. High burden of viruses and bacterial pathobionts drives heightened nasal innate immunity in children. Journal Of Experimental Medicine 2024, 221: e20230911. PMID: 38949638, PMCID: PMC11215523, DOI: 10.1084/jem.20230911.Peer-Reviewed Original ResearchConceptsBacterial pathobiontsRespiratory virusesBurden of virusesSARS-CoV-2Innate immune activationSARS-CoV-2 viral loadDynamic host-pathogen interactionsInnate immune responseViral coinfectionCytokine profileViral loadNasal virusImmune activationProinflammatory responseIL-1BNasopharyngeal samplesHost-pathogen interactionsImmune responseInterferon responsePathobiontsInnate immunityPaired samplesCXCL10Healthy 1-year-oldVirusSOFA score performs worse than age for predicting mortality in patients with COVID-19
Sherak R, Sajjadi H, Khimani N, Tolchin B, Jubanyik K, Taylor R, Schulz W, Mortazavi B, Haimovich A. SOFA score performs worse than age for predicting mortality in patients with COVID-19. PLOS ONE 2024, 19: e0301013. PMID: 38758942, PMCID: PMC11101117, DOI: 10.1371/journal.pone.0301013.Peer-Reviewed Original ResearchConceptsCrisis standards of careIn-hospital mortalityIntensive care unitAcademic health systemSequential Organ Failure Assessment scoreCohort of intensive care unitSequential Organ Failure AssessmentStandard of careLogistic regression modelsMortality predictionPredicting in-hospital mortalityHealth systemUnivariate logistic regression modelCrisis standardsDisease morbidityCOVID-19Hypertension Trends and Disparities Over 12 Years in a Large Health System: Leveraging the Electronic Health Records
Brush J, Lu Y, Liu Y, Asher J, Li S, Sawano M, Young P, Schulz W, Anderson M, Burrows J, Krumholz H. Hypertension Trends and Disparities Over 12 Years in a Large Health System: Leveraging the Electronic Health Records. Journal Of The American Heart Association 2024, 13: e033253. PMID: 38686864, PMCID: PMC11179912, DOI: 10.1161/jaha.123.033253.Peer-Reviewed Original ResearchConceptsElectronic health recordsRegional health systemImprove hypertension careHealth systemHealth recordsHypertension careDiastolic blood pressureAge-adjusted prevalence ratesNon-Hispanic Black patientsPrevalence ratesLarger health systemCross-sectional analysisTransformation of medical dataLeveraging real-world dataHigh prevalence rateHypertension trendsHypertension prevalenceBlood pressureBlood pressure measurementsHypertension diagnosisPrimary outcomeNational trendsProportion of patientsAntihypertensive medicationsBlack patients
2021
Effectiveness of ChAdOx1 vaccine in older adults during SARS-CoV-2 Gamma variant circulation in São Paulo
Hitchings MDT, Ranzani OT, Dorion M, D’Agostini T, de Paula RC, de Paula OFP, de Moura Villela EF, Torres MSS, de Oliveira SB, Schulz W, Almiron M, Said R, de Oliveira RD, Silva PV, de Araújo WN, Gorinchteyn JC, Andrews JR, Cummings DAT, Ko AI, Croda J. Effectiveness of ChAdOx1 vaccine in older adults during SARS-CoV-2 Gamma variant circulation in São Paulo. Nature Communications 2021, 12: 6220. PMID: 34711813, PMCID: PMC8553924, DOI: 10.1038/s41467-021-26459-6.Peer-Reviewed Original ResearchConceptsSingle doseOxford-AstraZeneca COVID-19 vaccineTest-negative case-control studySevere COVID-19 outcomesCOVID-19COVID-19-related deathsTwo-dose scheduleTwo-dose regimenCase-control studyCOVID-19 outcomesInter-dose intervalCOVID-19 hospitalizationCOVID-19 vaccineSARS-CoV-2ChAdOx1 vaccinePrimary endpointSecondary endpointsFirst doseSecond doseHigh prevalenceElderly individualsElderly populationVariant prevalenceVaccine supplyHospitalizationPrevalence of Dyslipidemia and Availability of Lipid-Lowering Medications Among Primary Health Care Settings in China
Lu Y, Zhang H, Lu J, Ding Q, Li X, Wang X, Sun D, Tan L, Mu L, Liu J, Feng F, Yang H, Zhao H, Schulz WL, Krumholz HM, Pan X, Li J, Huang C, Dong Z, Jiang B, Guo Z, Zhang Y, Sun J, Liu Y, Ren Z, Meng Y, Wang Z, Xi Y, Xing L, Tian Y, Liu J, Fu Y, Liu T, Sun W, Yan S, Jin L, Zheng Y, Wang J, Yan J, Xu X, Chen Y, Xing X, Zhang L, Zhong W, Fang X, Zhu L, Xu Y, Guo X, Xu C, Zhou G, Fan L, Qi M, Zhu S, Qi J, Li J, Yin L, Liu Q, Geng Q, Feng Y, Wang J, Wen H, Han X, Liu P, Ding X, Xu J, Deng Y, He J, Liu G, Jiang C, Zha S, Yang C, Bai G, Yu Y, Tashi Z, Qiu L, Hu Z, He H, Zhang J, Zhou M, Li X, Zhao J, Ma S, Ma Y, Huang Y, Zhang Y, Li F, Shen J. Prevalence of Dyslipidemia and Availability of Lipid-Lowering Medications Among Primary Health Care Settings in China. JAMA Network Open 2021, 4: e2127573. PMID: 34586366, PMCID: PMC8482054, DOI: 10.1001/jamanetworkopen.2021.27573.Peer-Reviewed Original ResearchConceptsAtherosclerotic cardiovascular diseaseLipid-lowering medicationsPrimary care institutionsPrevalence of dyslipidemiaControl of dyslipidemiaLipoprotein cholesterolCare institutionsControl rateFemale sexCardiovascular diseaseMAIN OUTCOMEHigh riskNonstatin lipid-lowering drugsHigh-density lipoprotein cholesterolLow-density lipoprotein cholesterolPrimary health care settingsMajor public health problemLipid lowering medicationsMillion Persons ProjectOverall control rateLDL-C levelsLipid-lowering drugsCross-sectional studyPublic health problemHealth care settingsEffectiveness of the CoronaVac vaccine in older adults during a gamma variant associated epidemic of covid-19 in Brazil: test negative case-control study
Ranzani OT, Hitchings MDT, Dorion M, D'Agostini TL, de Paula RC, de Paula OFP, Villela EFM, Torres MSS, de Oliveira SB, Schulz W, Almiron M, Said R, de Oliveira RD, Vieira da Silva P, de Araújo WN, Gorinchteyn JC, Andrews JR, Cummings DAT, Ko AI, Croda J. Effectiveness of the CoronaVac vaccine in older adults during a gamma variant associated epidemic of covid-19 in Brazil: test negative case-control study. The BMJ 2021, 374: n2015. PMID: 34417194, PMCID: PMC8377801, DOI: 10.1136/bmj.n2015.Peer-Reviewed Original ResearchConceptsSymptomatic COVID-19Negative case-control studyCase-control studyHospital admissionVaccine effectivenessSecond doseDose regimenElderly populationCOVID-19Reverse transcription polymerase chain reaction testingTranscription polymerase chain reaction testingPolymerase chain reaction testingGamma variantInactivated whole virus vaccineAdjusted vaccine effectivenessTest-negative controlsWhole virus vaccineCOVID-19 statusCOVID-19 symptomsYounger age groupsMunicipality of residenceSARS-CoV-2RT-PCR testSelf-reported raceCoronaVac vaccineDiverse functional autoantibodies in patients with COVID-19
Wang EY, Mao T, Klein J, Dai Y, Huck JD, Jaycox JR, Liu F, Zhou T, Israelow B, Wong P, Coppi A, Lucas C, Silva J, Oh JE, Song E, Perotti ES, Zheng NS, Fischer S, Campbell M, Fournier JB, Wyllie AL, Vogels CBF, Ott IM, Kalinich CC, Petrone ME, Watkins AE, Dela Cruz C, Farhadian S, Schulz W, Ma S, Grubaugh N, Ko A, Iwasaki A, Ring A. Diverse functional autoantibodies in patients with COVID-19. Nature 2021, 595: 283-288. PMID: 34010947, DOI: 10.1038/s41586-021-03631-y.Peer-Reviewed Original ResearchConceptsPeripheral immune cell compositionSARS-CoV-2 infectionCOVID-19Effects of autoantibodiesTissue-associated antigensSpecific clinical characteristicsInnate immune activationImmune cell compositionCOVID-19 exhibitCOVID-19 manifestsAnalysis of autoantibodiesSARS-CoV-2Functional autoantibodiesMouse surrogateClinical characteristicsVirological controlClinical outcomesImmune activationMild diseaseAsymptomatic infectionAutoantibody reactivityDisease progressionHealthcare workersHigh prevalenceAutoantibodiesDelayed production of neutralizing antibodies correlates with fatal COVID-19
Lucas C, Klein J, Sundaram ME, Liu F, Wong P, Silva J, Mao T, Oh JE, Mohanty S, Huang J, Tokuyama M, Lu P, Venkataraman A, Park A, Israelow B, Vogels CBF, Muenker MC, Chang CH, Casanovas-Massana A, Moore AJ, Zell J, Fournier JB, Wyllie A, Campbell M, Lee A, Chun H, Grubaugh N, Schulz W, Farhadian S, Dela Cruz C, Ring A, Shaw A, Wisnewski A, Yildirim I, Ko A, Omer S, Iwasaki A. Delayed production of neutralizing antibodies correlates with fatal COVID-19. Nature Medicine 2021, 27: 1178-1186. PMID: 33953384, PMCID: PMC8785364, DOI: 10.1038/s41591-021-01355-0.Peer-Reviewed Original ResearchConceptsDeceased patientsAntibody levelsAntibody responseDisease severityAnti-S IgG levelsCOVID-19 disease outcomesFatal COVID-19Impaired viral controlWorse clinical progressionWorse disease severitySevere COVID-19Length of hospitalizationImmunoglobulin G levelsHumoral immune responseCoronavirus disease 2019COVID-19 mortalityCOVID-19Domain (RBD) IgGSeroconversion kineticsDisease courseIgG levelsClinical parametersClinical progressionHumoral responseDisease onsetThe Association of COVID-19 With Acute Kidney Injury Independent of Severity of Illness: A Multicenter Cohort Study
Moledina DG, Simonov M, Yamamoto Y, Alausa J, Arora T, Biswas A, Cantley LG, Ghazi L, Greenberg JH, Hinchcliff M, Huang C, Mansour SG, Martin M, Peixoto A, Schulz W, Subair L, Testani JM, Ugwuowo U, Young P, Wilson FP. The Association of COVID-19 With Acute Kidney Injury Independent of Severity of Illness: A Multicenter Cohort Study. American Journal Of Kidney Diseases 2021, 77: 490-499.e1. PMID: 33422598, PMCID: PMC7791318, DOI: 10.1053/j.ajkd.2020.12.007.Peer-Reviewed Original ResearchMeSH KeywordsAcute Kidney InjuryAgedCohort StudiesCOVID-19C-Reactive ProteinCreatinineDiureticsFemaleHospital MortalityHumansIntensive Care UnitsLength of StayMaleMiddle AgedProportional Hazards ModelsRenal DialysisRenal Insufficiency, ChronicRespiration, ArtificialRisk FactorsSARS-CoV-2Severity of Illness IndexUnited StatesVasoconstrictor AgentsConceptsAcute kidney injurySARS-CoV-2Cohort studyRisk factorsCOVID-19Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testingTime-updated Cox proportional hazards modelsDialysis-requiring acute kidney injuryYale New Haven Health SystemHigher inflammatory marker levelsMore acute kidney injuryCox proportional hazards modelMulticenter cohort studyHigh rateInflammatory marker levelsTraditional risk factorsProportional hazards modelCoronavirus disease 2019KDIGO criteriaNephrotoxin exposureKidney injuryInjury independentUnivariable analysisNasopharyngeal samplesMarker levels
2020
Evaluation of a Risk Stratification Model Using Preoperative and Intraoperative Data for Major Morbidity or Mortality After Cardiac Surgical Treatment
Durant TJS, Jean RA, Huang C, Coppi A, Schulz WL, Geirsson A, Krumholz HM. Evaluation of a Risk Stratification Model Using Preoperative and Intraoperative Data for Major Morbidity or Mortality After Cardiac Surgical Treatment. JAMA Network Open 2020, 3: e2028361. PMID: 33284333, DOI: 10.1001/jamanetworkopen.2020.28361.Peer-Reviewed Original ResearchSex differences in immune responses that underlie COVID-19 disease outcomes
Takahashi T, Ellingson MK, Wong P, Israelow B, Lucas C, Klein J, Silva J, Mao T, Oh JE, Tokuyama M, Lu P, Venkataraman A, Park A, Liu F, Meir A, Sun J, Wang EY, Casanovas-Massana A, Wyllie AL, Vogels CBF, Earnest R, Lapidus S, Ott IM, Moore AJ, Shaw A, Fournier J, Odio C, Farhadian S, Dela Cruz C, Grubaugh N, Schulz W, Ring A, Ko A, Omer S, Iwasaki A. Sex differences in immune responses that underlie COVID-19 disease outcomes. Nature 2020, 588: 315-320. PMID: 32846427, PMCID: PMC7725931, DOI: 10.1038/s41586-020-2700-3.Peer-Reviewed Original ResearchConceptsInnate immune cytokinesFemale patientsMale patientsImmune cytokinesDisease outcomeImmune responseCOVID-19COVID-19 disease outcomesPoor T cell responsesSARS-CoV-2 infectionSevere acute respiratory syndrome coronavirusAcute respiratory syndrome coronavirusSex-based approachModerate COVID-19Sex differencesRobust T cell activationT cell responsesWorse disease progressionWorse disease outcomesHigher plasma levelsNon-classical monocytesCoronavirus disease 2019T cell activationImmunomodulatory medicationsPlasma cytokinesLongitudinal analyses reveal immunological misfiring in severe COVID-19
Lucas C, Wong P, Klein J, Castro TBR, Silva J, Sundaram M, Ellingson MK, Mao T, Oh JE, Israelow B, Takahashi T, Tokuyama M, Lu P, Venkataraman A, Park A, Mohanty S, Wang H, Wyllie AL, Vogels CBF, Earnest R, Lapidus S, Ott IM, Moore AJ, Muenker MC, Fournier JB, Campbell M, Odio CD, Casanovas-Massana A, Herbst R, Shaw A, Medzhitov R, Schulz W, Grubaugh N, Dela Cruz C, Farhadian S, Ko A, Omer S, Iwasaki A. Longitudinal analyses reveal immunological misfiring in severe COVID-19. Nature 2020, 584: 463-469. PMID: 32717743, PMCID: PMC7477538, DOI: 10.1038/s41586-020-2588-y.Peer-Reviewed Original ResearchConceptsSevere COVID-19Moderate COVID-19Immune signaturesDisease outcomeCOVID-19Disease trajectoriesInterleukin-5Early immune signaturesInnate cell lineagesType 2 effectorsT cell numbersPoor clinical outcomeWorse disease outcomesImmune response profileCoronavirus disease 2019Distinct disease trajectoriesCytokine levelsImmunological correlatesImmune profileClinical outcomesEarly elevationImmune profilingIL-13Immunoglobulin EDisease 2019Development and Validation of the Quick COVID-19 Severity Index: A Prognostic Tool for Early Clinical Decompensation
Haimovich AD, Ravindra NG, Stoytchev S, Young HP, Wilson FP, van Dijk D, Schulz WL, Taylor RA. Development and Validation of the Quick COVID-19 Severity Index: A Prognostic Tool for Early Clinical Decompensation. Annals Of Emergency Medicine 2020, 76: 442-453. PMID: 33012378, PMCID: PMC7373004, DOI: 10.1016/j.annemergmed.2020.07.022.Peer-Reviewed Original ResearchMeSH KeywordsAdolescentAdultAgedBetacoronavirusClinical Laboratory TechniquesCoronavirus InfectionsCOVID-19COVID-19 TestingEmergency Service, HospitalFemaleHumansMaleMiddle AgedOxygen Inhalation TherapyPandemicsPneumonia, ViralRespiratory InsufficiencyRetrospective StudiesRisk AssessmentSARS-CoV-2Severity of Illness IndexYoung AdultConceptsCOVID-19 Severity IndexQuick COVID-19 severity indexQuick Sequential Organ Failure AssessmentSequential Organ Failure AssessmentOrgan Failure AssessmentHours of admissionRespiratory failureSeverity IndexScoring systemSevere acute respiratory syndrome coronavirus 2Acute respiratory syndrome coronavirus 2Respiratory syndrome coronavirus 2Bedside scoring systemOxygen requirementPneumonia severity scoresHours of hospitalizationElixhauser Comorbidity IndexEmergency department patientsSeverity Index scoreCOVID-19 patientsSyndrome coronavirus 2Coronavirus disease 2019Failure AssessmentSimple scoring systemIndependent test cohortRates and Predictors of Patient Underreporting of Hospitalizations During Follow-Up After Acute Myocardial Infarction
Caraballo C, Khera R, Jones PG, Decker C, Schulz W, Spertus JA, Krumholz HM. Rates and Predictors of Patient Underreporting of Hospitalizations During Follow-Up After Acute Myocardial Infarction. Circulation Cardiovascular Quality And Outcomes 2020, 13: e006231. PMID: 32552061, PMCID: PMC9465954, DOI: 10.1161/circoutcomes.119.006231.Peer-Reviewed Original ResearchConceptsAcute myocardial infarctionMyocardial infarctionHospitalization eventsMedical recordsLongitudinal multicenter cohort studyMulticenter cohort studyMedical record abstractionDifferent patient characteristicsHealth care eventsPatients' underreportingTRIUMPH registryAccuracy of reportingCohort studyPatient characteristicsRecord abstractionProspective studyClinical studiesClinical investigationHospitalizationPatientsCare eventsInfarctionEvent ratesParticipantsPredictorsLeveraging the Electronic Health Records for Population Health: A Case Study of Patients With Markedly Elevated Blood Pressure
Lu Y, Huang C, Mahajan S, Schulz WL, Nasir K, Spatz ES, Krumholz HM. Leveraging the Electronic Health Records for Population Health: A Case Study of Patients With Markedly Elevated Blood Pressure. Journal Of The American Heart Association 2020, 9: e015033. PMID: 32200730, PMCID: PMC7428633, DOI: 10.1161/jaha.119.015033.Peer-Reviewed Original ResearchConceptsDiastolic blood pressureSystolic blood pressureElevated blood pressureBlood pressureElectronic health recordsPopulation health surveillanceHealth recordsYale New Haven Health SystemHealth surveillanceHealth systemPatterns of patientsLarge health systemUsual careOutpatient encountersControl ratePatientsCare patternsPopulation healthMonthsHgSurveillancePrevalenceRecordsVisitsCare
2019
Blood utilisation and transfusion reactions in adult patients transfused with conventional or pathogen‐reduced platelets
Bahar B, Schulz WL, Gokhale A, Spencer BR, Gehrie EA, Snyder EL. Blood utilisation and transfusion reactions in adult patients transfused with conventional or pathogen‐reduced platelets. British Journal Of Haematology 2019, 188: 465-472. PMID: 31566724, PMCID: PMC7003815, DOI: 10.1111/bjh.16187.Peer-Reviewed Original ResearchConceptsPathogen-reduced plateletsTransfusion reactionsPlatelet componentsAdult patientsPlatelet transfusionsSeptic transfusion reactionsRed blood cell transfusion requirementsPR plateletsYale-New Haven HospitalPlatelet component transfusionsComparable clinical efficacyType of transfusionTransfusion requirementsTransfusion trendsPlatelet administrationComponent transfusionClinical efficacyNumber of RBCsConventional plateletsBlood utilisationPatientsTransfusionMean timePlateletsRBCsTraditional Chinese Medicine Use in the Treatment of Acute Heart Failure in Western Medicine Hospitals in China: Analysis From the China PEACE Retrospective Heart Failure Study
Yu Y, Spatz ES, Tan Q, Liu S, Lu Y, Masoudi FA, Schulz WL, Krumholz HM, Li J, Group T. Traditional Chinese Medicine Use in the Treatment of Acute Heart Failure in Western Medicine Hospitals in China: Analysis From the China PEACE Retrospective Heart Failure Study. Journal Of The American Heart Association 2019, 8: e012776. PMID: 31364457, PMCID: PMC6761625, DOI: 10.1161/jaha.119.012776.Peer-Reviewed Original ResearchConceptsTraditional Chinese medicineAcute heart failureHeart failureEvidence-based therapiesWestern Medicine HospitalTCM useMedicine HospitalEvidence-based therapy useTraditional Chinese medicine useChinese medicine useCoronary artery diseaseHeart Failure StudyHierarchical logistic regression modelsLogistic regression modelsSalvia miltiorrhizaRandom sampleHospital bleedingPatient's bleedingPatient characteristicsArtery diseaseTherapy useMedicine useHospital characteristicsRetrospective analysisHospital use