现场流行病学基石——病例定义PPT课件.ppt

现场流行病学的基石病例定义,刘明斌2010年2月25日,南昌市疾病预防控制中心中国现场流行病学培训项目,1,主要内容Contents,为什么要使用病例定义？Whyuseacasedefinition?什么是病例定义？Whatisacasedefinition?敏感度和特异度问题Sensitivityandspecificity构建病例定义Constructionofcasedefinitions监测系统病例定义应用实例Applyingcasedefinitions病例一览表LineListing疾病的时间序列Timesequenceofillness,2,为什么使用病例定义?Whyuseacasedefinition?,医生、护士、实验室和其他人员依法报告Doctors,nurses,laboratories,andothersreportnotifiableevents资料产生外在变异Producesextraneousvariabilityinthesedata减少变异性以便：Needtominimizethisvariabilityto:监视趋势Monitortrends评价干预效果Evaluatetheeffectivenessofinterventionactivities地区间的比较Compareareas比较结果应真实反应疾病本身的变化和不同Comparisonsmustreflectchangesordifferencesinthedisease,3,疾病监测的病例定义必须始终保持一致Casedefinitionsforsurveillanceneedtobeconsistentovertime.,报告病例数ReportedCases,年份Quarteryear,4,20052006年某社区病毒性肝炎每周报告发病率ViralHepatitisbyweekforonecounty,2005-2006,乙肝HBV,未分型肝炎Unspecifiedhepatitis,5,20052006年某社区剔除社区医院的病毒性肝炎每周报告发病率ViralHepatitisforacountywithandwithoutonehospital,2005-2006,剔除社区医院,社区总报告发病率,6,病例的错误分类可导致流行病学分析偏差Misclassifiedcasescanbiasepidemiologicanalysis,7,完美的病例分类则可给出不同的率Perfectclassificationgivesdifferentrates,8,在消灭某种疾病X的过程中与其相似疾病的发病率等于10DuringeliminationofdiseaseXtheincidenceofsimilardisease=10,相似疾病Similardisease,疾病XDiseaseX,监测到的疾病总数Totaldiseasedetected,9,在消灭某种疾病X的过程中与其相似疾病的发病率等于1DuringeliminationofdiseaseXtheincidenceofsimilardisease=1,监测到的病例总数Totaldiseasedetected,疾病XDiseaseX,相似疾病Similardisease,10,什么是病例定义?Whatisacasedefinition?,一套标准Asetofstandardcriteria用于确定是否感染Usedtodecideifapersonhasaninfection保证卫生统计结果是真实可信的Assuresthatdifferencesinhealthstatisticsarereal根据目的不同而不同Varieswiththepurpose,11,不同专家会对同一（群）病人进行相同分类吗？Willexpertsclassifythesamepatientsthesame?,10位专家会诊100位病人10expertsreview100patients每位专家均将他们划分为某病病人或非病人EachexpertclassifiesthemasacaseornotacaseofadiseaseX每位专家会按同样方法对每位病人进行分类吗？Willeveryexpertclassifyeverypatientthesameway?Caseornotacase?,12,是否可能存在完美专家？Willoneexpertbeperfect?,假设一位专家审阅100位病人的诊疗记录Oneexpertreviews100patientrecords.他将如何判定病人与非病人？AcaseornotacaseofadiseaseX?一个月后同一专家重新审阅上述100位病人的诊疗记录又将如何？Onemonthlatertheexpertreviewsthesame100records.不同专家将会用同一方法或标准判定每位病人？Willeveryexpertclassifyeverypatientthesameway?Caseornotacase?,13,一个典型的病例定义（临床诊断）：麻疹Atypicalcasedefinition:measles,出皮疹37天Generalizedskinrashof3to7daysduration体温大于38度Fever38C加上以下一项或多项Plusoneormoreofthefollowing鼻卡他症状coryza(鼻塞stuffy,流涕runnynose)咳嗽cough结膜充血conjunctivalinjection,14,敏感度和特异度Sensitivityandspecificity,敏感度Sensitivity能够发现的病例占所有真实病例的比例ofallthetruecasesofthediseasehowmany(whatpercentorproportion)doesthemethoddiscover?特异度Specificity能够发现的非病例占所有非病例的比例ofallthenon-caseshowmany(whatpercentorproportion)doesthemethoddiscover?,15,病例定义永远不可能完美Casedefinitionsareneverperfect,16,敏感度等于真实病例被准确判定的比例Sensitivity=proportionoftruecasescorrectlyidentified,敏感度Sensitivity=90/100=0.90=90%,假阴性率Percentagefalsenegatives=10/100=0.10=10%,17,特异度等于非病例被准确判定的比例Specificity=theproportionofnon-casescorrectlyidentified,特异度Specificity=80/100=0.80=80%,假阳性率Percentagefalsepositives=20/100=0.20=20%,18,假定某社区在疾病X暴发期间同时存在其它不同疾病ConsideracountywithdifferentdiseasesduringanoutbreakofDiseaseX.,与疾病X相似SimilaritytodiseaseX,其它疾病Otherdiseases,疾病XDiseaseX,19,高度敏感的病例定义必将包括很多其它疾病的病例Acasedefinitionthatincludesallcaseswillincludemanyotherdiseases,高度敏感的病例定义Thisiscalleda“highlysensitive”casedefinition,非病例NotCases,20,高度特异的病例定义必将排除包括很多真实病例Acasedefinitionthatincludesonlycaseswillexcludemanycases,X疾病病例DiseaseX,高度特异的病例定义Thisiscalleda“highlyspecific”casedefinition,非病例NotCases,21,病例定义可有多个水平Thecasedefinitionmayhavelevelsofcertainty.,非病例NotCases,疑似病例Suspect,可能病例Possible,临床病例Probable,确诊病例Confirmed,特异度Specificity,敏感度Sensitivity,22,细菌性痢疾暴发的病例定义Casedefinitionforashigellosisoutbreak,非病例NotCases,腹泻Diarrhea2days,Diarrhea2days+呕吐Vomit或者OR发烧Fever38C,Diarrhea2days+Vomit并且ANDFever38C,Suspect,orPossible,orProbable+实验室阳性Shigella,疑似病例Suspect,可能病例Possible,临床病例Probable,确诊病例Confirmed,23,敏感度和特异度可随目标的不同而变化Variabilityinsensitivityandspecificitydependsonpurpose,诊断和治疗Diagnosisandtreatmentofpatients.流行病学调查阶段Phaseofanepidemiologicinvestigation确证暴发原因Toidentifycause常规监测或疾病登记Forroutinesurveillanceorregistries内部或者外部使用Forinternalorexternaluse,24,暴发期间使用敏感病例定义Duringoutbreakstheperformanceofasensitivecasedefinitionimproves,相似疾病,暴发疾病,疾病暴发,25,构建病例定义Constructionofcasedefinitions,26,疾病识别标志：DiseaseIdentifiers:,症状Symptomatology体征（物理检查）Signs(Physicalexamination)临床评价Clinicalevaluations(EKG,EEG,etc.)不符合其他疾病Lackofcompatibilitywithotherdiseases治疗情况Responsetotreatment实验室检测（病毒分离、血糖等）Laboratorytests(virusisolation,bloodsugar,etc.),27,流行病学标准Epidemiologiccriteria,时间Time地点Place人Person宿主因素（基础疾病）Hostfactors(underlyingillness)与其它病例的流行病学联系Linkagestoothercases相关危险因素Associationswithriskfactors,28,感染性胃肠炎：病例定义示例Infectiousgastroenteritis:Examplecasedefinition,临床Clinical:腹泻（3次以上稀便x2天）Diarrhea(3+liquidstoolsx2days)发热Fever无其他原因（药物抗生素）Noothercause(drugs-antibiotics)实验室确诊ConfirmedLaboratory:粪便中发现病原体Organismidentifiedinstool流行病学Epidemiological在最短潜伏期内住院Hospitalizedforminimumincubationperiod潜伏期期间在医院Inhospitalduringincubation,29,使用一个大多数或全部病例具有的症状特征Useonecharacteristicthatwillincludemostorallcases,腹泻Diarrhea发热Fever黄疸Jaundice出疹Rash出疹并发热Rash+fever咳嗽并发热Cough+fever,30,使用在某些病例中发现的更具特异性的症状特征Usemorespecificcharacteristicsthatareseeninsomecases,特殊发现Specificfindings杨梅舌猩红热Strawberrytongue-scarletfever特殊病症Pathognomonicfinding柯氏斑麻疹Koplicksspots=measles,31,使用一组一般性的症状特征Useagroupofcommonfindings,卡他症状Coryza咳嗽Cough结膜炎Conjunctivitis,32,其它标准Othercriteria,不能被其它已知疾病所能解释的症状Symptomsnotexplainedbyanotherconfirmeddiseaseorcondition既往健康人所具有的特征Inapreviouslyhealthyperson,33,川崎病Kawasakidisease,发热持续5天或以上Febrileillnessfor5ormoredays并同时具有以下5种症状中的4种Withfourofthefollowingfivefindings双眼结膜充血Bilateralconjunctivalinjection新发口腔粘膜破损Orallesions(new)手指和脚趾破损Lesionsonfingersandtoes皮疹Skinrash颈部淋巴结病Cervicallymphadenopathy,34,新生儿破伤风NeonatalTetanus,新生儿Neonatewho出生时啼哭Criedatbirth出生后头两天内能正常吸允Hadnormalsuckforfirst2daysoflife出生后第3天至30天以内Developedfrom3to30daysafterbirth无力吸允Inabilitytosuck出现痉挛Generalizedspasticity可有惊厥Withorwithoutconvulsions死亡Commonlyresultsindeath,35,百日咳Pertussis,咳嗽并具有以下任一特征Coughwithoneofthefollowingcharacteristics咳嗽持续2周或2周以上Continuesfor2ormoreweeks阵发Withparoxysms咳嗽后呕吐Posttussivevomiting,36,病例定义应用实例Applyingcasedefinitions,37,举例：人狂犬病监测病例定义的标准Examplecriteriaforacasedefinitionforhumanrabiesforsurveillance,临床标准Clinical:脑炎Encephalitis发病后10天内死亡Deathwithin10daysofonset实验室标准Laboratory:头发毛囊、角膜或者脑组织免疫荧光抗体染色阳性DirectFAofhairfollicle,corneaorbrain抗狂犬病毒IgG或IgM抗体阳性（未经免疫者）Anti-rabiesIgGorIgMinanunvaccinatedperson流行病学标准Epidemiological:被已知宿主动物咬伤Bitefromaknownreservoiranimalspecies被患狂犬病的动物咬伤Bitefromarabidanimal,38,举例：狂犬病病例定义Examplerabiescasedefinition,疑似病例Suspect患脑炎并于10天内死亡Encephalitiswithdeathin10days可能病例=疑似病例Possible=suspectand动物咬伤animalbite临床诊断病例=疑似病例Probable=suspectand被患狂犬病的动物咬伤bitefromrabidanimal确诊病例=疑似病例、可能病例或者临床诊断病例Confirmed=suspect,possibleorprobable免疫荧光抗体检测狂犬病毒阳性RabiesvirusbydirectFAfromcornea,hairfollicle,orbrain或者抗狂犬病毒IgM抗体阳性（未经免疫者）Oranti-rabiesIgMinanunvaccinatedperson,39,根据以下报告的狂犬病例数据，哪些病例符合病例定义？Somedatafromreportedrabiescases.Whichfitthecasedefinitions?,E=脑炎encephalitisY=是YesN=否NoR=患狂犬病的动物RabidAnimal,O=其它动物otheranimalND=没有检测NotdoneCI=角膜印迹CornealImpressionBr=脑组织Brain,40,腮腺炎性脑膜脑炎Mumpsmeningoencephalitis,临床标准Clinical脑膜炎或脑炎症状并发热大于37.5度Symptomsofmeningitisorencephalitiswithfever(37.5C)脑脊液白细胞计数大于50个/ml、葡萄糖大于3,0um/LCSFwith50leucocytes/mlyglucose3,0um/L前2周内患有流行性腮腺炎Mumpsdiseasewithin2weeksbefore流行病学标准Epidemiologic发病前一个月与流行性腮腺炎患者面对面接触过Face-to-facecontactwithamumpscaseinthemonthbeforeonset实验室确诊标准Laboratoryconfirmation抗腮腺炎病毒IgM抗体Anti-mumpsIgM分离到腮腺炎病毒Isolationofmumpsvirus,41,流行性腮腺炎性脑膜炎MumpsMeningitis,疑似病例Suspect症状加接触Symptomspluscontact可能病例Possible症状加流行性腮腺炎Symptomsplusmumpsdisease临床诊断病例Probable疑似或者可能病例加脑脊液检查SuspectorpossiblewithcompatibleCSF确诊病例Confirmed上述三种病例Suspect,possibleorprobable急性期或恢复期检测到IgM抗体或分离到腮腺炎病毒Anti-mumpsIgMorisolationofmumpsvirusduringacuteillnessorconvalescence,42,根据以下病例一览表判定哪些病例符合病例定义Canyouapplythecasedefinitiontothisline-listingofpatients?,43,病例一览表ExampleofaLineListing,1=“Yes”?=“Dontknow”0=“No”,44,如何制作一览表HowtoCreateaLineListing,及时添加新的确诊病例Addnewcasesastheyareidentified在调查过程中保持更新所有病例信息Updatecaseinformationthroughouttheinvestigation根据情况设置变量数量Numberofvariablestoincludewillvary变量少利于目测Fewe