Health Care CostsMultivariate AnalysisCosts and Cost AnalysisCost of IllnessDrug CostsCost ControlRisk FactorsSeverity of Illness IndexDirect Service CostsRetrospective StudiesCost-Benefit AnalysisPrognosisCost SharingCritical IllnessCost AllocationUnited StatesProspective StudiesTreatment OutcomeLogistic ModelsTime FactorsCohort StudiesFollow-Up StudiesCross-Sectional StudiesAge FactorsQuestionnairesSurvival AnalysisMental DisordersRegression AnalysisPredictive Value of TestsSurvival RateProportional Hazards ModelsPrevalenceChronic DiseaseHospitalizationModels, EconomicIncidenceIllness BehaviorInfant, NewbornCase-Control StudiesRisk AssessmentOdds RatioAnalysis of VarianceSocioeconomic FactorsSex FactorsComorbidityKaplan-Meier EstimateEmployer Health CostsLength of StayQuality-Adjusted Life YearsNeoplasm StagingDisease-Free SurvivalAcute DiseaseLinear ModelsQuality of LifeSensitivity and SpecificityLongitudinal StudiesChi-Square DistributionInfluenza, HumanRecurrenceFeverPopulation SurveillanceTumor Markers, BiologicalHealth ResourcesAttitude to HealthHealth StatusReproducibility of ResultsOutcome Assessment (Health Care)Models, StatisticalRespiratory Tract InfectionsBiological MarkersDisease ProgressionHIV InfectionsGreat BritainBreast NeoplasmsSick RolePatient Acceptance of Health CareAmbulatory CareHealth SurveysConfidence IntervalsRiskData CollectionRural PopulationAge DistributionInsurance Claim ReviewFoodborne DiseasesDemographyPregnancyIntensive Care UnitsSmokingAlgorithmsCaliforniaEnglandHealth Services AccessibilityMentally Ill PersonsRespiratory Tract DiseasesInterviews as TopicEpidemiologic MethodsChinaPrincipal Component AnalysisEfficiency