NR 503 Final Exam Study Guide
i i i i i
• Be isure ito ireview ithe iterminology iand iconcepts iof ithe ifirst ifour iweeks: i these iconcepts ihelp ito
iinform iand isupport ithe ilast ifour iweeks iof ithe icourse.
• All iinformation ilisted ion ithis ireview idoc ican ibe ifound iin ithe icourse itext, iGordis.
Definitions iof istudy idesigns: iChapter i10: iDifferentiate ibetween ithe icase-control iand icohort istudies.
iAsk iyourself, iwhich iis iused iwhen, iand iwhy.
Case-Control:
• Examine ithe ipossible irelationship iof ian iexposure ito ia icertain idisease
• Identify igroup iof iindividuals iwith ithe idisease i(cases)
• For icomparison, igather ia igroup iof ipeople iwithout ithat idisease i(controls)
• Determine iwhat iproportion iof ithe icases iwere iexposed iand iwere inot
• Also idetermine iwhat iproportion iof ithe icontrols iwere iexposed iand inot
• Text: i Thus, iin ia icase-control istudy, iif ithere iis ian iassociation iof ian iexposure iwith ia idisease, ithe
iprevalence iof ihistory iof iexposure ishould ibe ihigher iin ipersons iwho ihave ithe idisease i(cases)
ithan iin ithose iwho ido inot ihave ithe idisease i(controls).
• Ask iyourself: i Why iis ithis iimportant ito ithe iNP iin iprimary icare? i How idoes ithis iinform ia
provider’s idecision-making?
Cohort iStudies: i Chapter i13: i Comparing iCohort iand iCase-Control iStudies: i See iFigure i13-1 iand i13-2
i(busy ipictures ibut ihang iin ithere)
Chapter i13 icomparison iof istudies i- iimportant ito ireview
Matching: iChapter i10: iText: iA imajor iconcern iin iconducting ia icase-control istudy iis ithat icases iand
icontrols imay idiffer iin icharacteristics ior iexposures iother ithan ithe ione ithat ihas ibeen itargeted ifor istudy.
Randomization: iThe ipoint iof irandomization iis ito iprevent iany ipotential ibiases ion ithe ipart iof ithe
iinvestigators/researchers. iText: iThus, ithe iuse iof irandomization iis icrucial ito iprotect ithe istudy ifrom iany
ibiases ithat imight ibe iintroduced iconsciously ior isubconsciously iby ithe iinvestigator iinto ithe iassignment
iprocess.
Bias: i(selection ibias) i(source iof icases) iIssues irelated ito igeneralizability; icases ifrom ia isingle isource iless
ithan idesirable ithan iif ifrom imultiple isources iwith ia ivarying ipool iof icases. i Ask iyourself, iwhy?
Causality: i Table i14-3: i Using ithe iEvidence iin iDeveloping iRecommendations
Cross-Sectional iStudy: iBoth iexposure iand idisease ioutcome iare idetermined isimultaneously ifor ieach
isubject. iTesting ia iperson ifor ithe irelationship ibetween ithe iexposure i(or iexistence iof idisease) iwith
ievidence iof ithe idisease. i See ifigure i10-13 iand iexample iof iserum icholesterol iand iECG.
Incidence iDensity iSampling: iText: iAn iimportant iconsideration iin icase-control istudies iis iwhether ito
iinclude iincident icases iof ia idisease i(newly idiagnosed icases) ior iprevalent icases iof ithe idisease i(people
iwho imay ihave ihad ithe idisease ifor isome itime).
Hypothesis: i Confirm ior irefute ibased iupon istudy; istatement iof iproposed irelationship
, Bradford-Hill iCriterion: iEpidemiologist, istatistician, ideveloped ithe iguidelines ifor ievaluating iwhether
ian iobserved iassociation iis icasual.
• Temporal irelationship
• Strength iof ithe iassociation
• Dose-response irelationship
• Replication iof ithe ifindings
• Biological iplausibility
• Consideration iof ialternate iexplanations
• Cessation iof iexposure
• Consistency iwith iother iknowledge
• Specificity iof ithe iassociation
Epidemiologic iTransition: i Trends ior ichanges iwith itime: i Figure i4-26
Ratio iMeasure iof iAssociation: i Proportional idescription iof iassociation, istrength.
Positive iPredictive iValue i(influencers iof ivalue) iRelate ithis ito iscreening itests; iwhat ivalues iare iused ito
icalculate ithe iPPV.
Odds iRatio: i The iodds iratio iis ithe iprobability, ithe iodds ithat ithe ievent iwill ihappen i(sort iof ilike ibetting).
Prevalence iRate: iThe inumber iof iaffected ipeople iin ithe ipopulation iat ia ispecific itime…. iDivided iby ithe
inumber iof ipersons iin ithe ipopulation iat ithat itime i– ithis itells ithe iproportion iof ithe ipopulation iaffected iby
ithe idisease iat ithat itime. iWhy iis ithis iimportant ito iunderstand??! iSo, iif ithe iprevalence irate iis ilow, ior
igoing idown, iit itells ius ithat i(perhaps) ithe iinterventions iwe iare iimplementing iare iuseful, iworking, ior ithat
iother iconditions/situations ihave ichanged iindicating ia idecreasing iprevalence irate. iOR, iif iit iis igoing iup,
iwhat imight ithat iindicate? i Ineffective iinterventions? i Demographic ichanges? i Etc….
Incidence iRate: iMeasures iof iMorbidity: i Text: i The iincidence irate iof ia idisease iis idefined ias ithe inumber
iof inew icases iof ia idisease ithat ioccur iduring ia ispecified iperiod iof itime iin ia ipopulation iat irisk ifor
ideveloping ithe idisease. i Text: i The icritical ielement iin idefining iincidence irate iis i NEW icases iof idisease.
Relative iRisk: iBoth icase-control iand icohort istudies ilook ifor ian iassociation ibetween iexposure ito ia
i“something” iand idevelopment iof ia idisease. iFor iinstance, iassociation ibetween iexposure ito isun iand ithe
idevelopment iof iskin icancer, imelanoma. iAnd ithen ithe inext istep iis ito iask, iis ithe irelationship ia istrong
irelationship ior iis iit ia iweak irelationship, ithis ihelps ius iin iour icare idelivery ibut iassigning ipriority ito ithe
iassociation, irisk. iThe iratio iof ithe irisk iof idisease iin ithe iexposed iindividual iis iconsidered ithe irelative irisk.
iAnother iway ithis iis isaid iis irelative irisk icould ibe ithe ilikelihood ior iprobability iof ideveloping ithe idisease iin
ithose iexposed icompared ito ithose inon-exposed, iso i….the iratio ibetween ithe itwo igroups.
Prospective iStudy: i Ask iyourself, iwhat iis ithe itime iframe? i Forward ior iback?
Controls: iSelection i/ isource iof icontrols i“Best ifriend icontrols” iAnother iapproach ito icontrol iselection iis
ito iuse ia ibest ifriend icontrol. iIn ithis iapproach, ia iperson iwho ihas ibeen iselected ias ia icase iis iasked ifor ithe
iname iof ia ibest ifriend iwho imay ibe imore ilikely ito iparticipate iin ithe istudy iknowing ithat ihis ior iher ibest
ifriend iis ialso iparticipating. iHowever, ithere iare ialso idisadvantages ito ithis imethod iof iselecting icontrols. iA
ibest ifriend icontrol iobtained iin ithis ifashion imay ibe isimilar ito ithe icase iin iage iand iin imany iother
idemographic iand isocial icharacteristics. iA iresulting iproblem imay ibe ithat ithe icontrols imay ibe itoo isimilar
i i i i i
• Be isure ito ireview ithe iterminology iand iconcepts iof ithe ifirst ifour iweeks: i these iconcepts ihelp ito
iinform iand isupport ithe ilast ifour iweeks iof ithe icourse.
• All iinformation ilisted ion ithis ireview idoc ican ibe ifound iin ithe icourse itext, iGordis.
Definitions iof istudy idesigns: iChapter i10: iDifferentiate ibetween ithe icase-control iand icohort istudies.
iAsk iyourself, iwhich iis iused iwhen, iand iwhy.
Case-Control:
• Examine ithe ipossible irelationship iof ian iexposure ito ia icertain idisease
• Identify igroup iof iindividuals iwith ithe idisease i(cases)
• For icomparison, igather ia igroup iof ipeople iwithout ithat idisease i(controls)
• Determine iwhat iproportion iof ithe icases iwere iexposed iand iwere inot
• Also idetermine iwhat iproportion iof ithe icontrols iwere iexposed iand inot
• Text: i Thus, iin ia icase-control istudy, iif ithere iis ian iassociation iof ian iexposure iwith ia idisease, ithe
iprevalence iof ihistory iof iexposure ishould ibe ihigher iin ipersons iwho ihave ithe idisease i(cases)
ithan iin ithose iwho ido inot ihave ithe idisease i(controls).
• Ask iyourself: i Why iis ithis iimportant ito ithe iNP iin iprimary icare? i How idoes ithis iinform ia
provider’s idecision-making?
Cohort iStudies: i Chapter i13: i Comparing iCohort iand iCase-Control iStudies: i See iFigure i13-1 iand i13-2
i(busy ipictures ibut ihang iin ithere)
Chapter i13 icomparison iof istudies i- iimportant ito ireview
Matching: iChapter i10: iText: iA imajor iconcern iin iconducting ia icase-control istudy iis ithat icases iand
icontrols imay idiffer iin icharacteristics ior iexposures iother ithan ithe ione ithat ihas ibeen itargeted ifor istudy.
Randomization: iThe ipoint iof irandomization iis ito iprevent iany ipotential ibiases ion ithe ipart iof ithe
iinvestigators/researchers. iText: iThus, ithe iuse iof irandomization iis icrucial ito iprotect ithe istudy ifrom iany
ibiases ithat imight ibe iintroduced iconsciously ior isubconsciously iby ithe iinvestigator iinto ithe iassignment
iprocess.
Bias: i(selection ibias) i(source iof icases) iIssues irelated ito igeneralizability; icases ifrom ia isingle isource iless
ithan idesirable ithan iif ifrom imultiple isources iwith ia ivarying ipool iof icases. i Ask iyourself, iwhy?
Causality: i Table i14-3: i Using ithe iEvidence iin iDeveloping iRecommendations
Cross-Sectional iStudy: iBoth iexposure iand idisease ioutcome iare idetermined isimultaneously ifor ieach
isubject. iTesting ia iperson ifor ithe irelationship ibetween ithe iexposure i(or iexistence iof idisease) iwith
ievidence iof ithe idisease. i See ifigure i10-13 iand iexample iof iserum icholesterol iand iECG.
Incidence iDensity iSampling: iText: iAn iimportant iconsideration iin icase-control istudies iis iwhether ito
iinclude iincident icases iof ia idisease i(newly idiagnosed icases) ior iprevalent icases iof ithe idisease i(people
iwho imay ihave ihad ithe idisease ifor isome itime).
Hypothesis: i Confirm ior irefute ibased iupon istudy; istatement iof iproposed irelationship
, Bradford-Hill iCriterion: iEpidemiologist, istatistician, ideveloped ithe iguidelines ifor ievaluating iwhether
ian iobserved iassociation iis icasual.
• Temporal irelationship
• Strength iof ithe iassociation
• Dose-response irelationship
• Replication iof ithe ifindings
• Biological iplausibility
• Consideration iof ialternate iexplanations
• Cessation iof iexposure
• Consistency iwith iother iknowledge
• Specificity iof ithe iassociation
Epidemiologic iTransition: i Trends ior ichanges iwith itime: i Figure i4-26
Ratio iMeasure iof iAssociation: i Proportional idescription iof iassociation, istrength.
Positive iPredictive iValue i(influencers iof ivalue) iRelate ithis ito iscreening itests; iwhat ivalues iare iused ito
icalculate ithe iPPV.
Odds iRatio: i The iodds iratio iis ithe iprobability, ithe iodds ithat ithe ievent iwill ihappen i(sort iof ilike ibetting).
Prevalence iRate: iThe inumber iof iaffected ipeople iin ithe ipopulation iat ia ispecific itime…. iDivided iby ithe
inumber iof ipersons iin ithe ipopulation iat ithat itime i– ithis itells ithe iproportion iof ithe ipopulation iaffected iby
ithe idisease iat ithat itime. iWhy iis ithis iimportant ito iunderstand??! iSo, iif ithe iprevalence irate iis ilow, ior
igoing idown, iit itells ius ithat i(perhaps) ithe iinterventions iwe iare iimplementing iare iuseful, iworking, ior ithat
iother iconditions/situations ihave ichanged iindicating ia idecreasing iprevalence irate. iOR, iif iit iis igoing iup,
iwhat imight ithat iindicate? i Ineffective iinterventions? i Demographic ichanges? i Etc….
Incidence iRate: iMeasures iof iMorbidity: i Text: i The iincidence irate iof ia idisease iis idefined ias ithe inumber
iof inew icases iof ia idisease ithat ioccur iduring ia ispecified iperiod iof itime iin ia ipopulation iat irisk ifor
ideveloping ithe idisease. i Text: i The icritical ielement iin idefining iincidence irate iis i NEW icases iof idisease.
Relative iRisk: iBoth icase-control iand icohort istudies ilook ifor ian iassociation ibetween iexposure ito ia
i“something” iand idevelopment iof ia idisease. iFor iinstance, iassociation ibetween iexposure ito isun iand ithe
idevelopment iof iskin icancer, imelanoma. iAnd ithen ithe inext istep iis ito iask, iis ithe irelationship ia istrong
irelationship ior iis iit ia iweak irelationship, ithis ihelps ius iin iour icare idelivery ibut iassigning ipriority ito ithe
iassociation, irisk. iThe iratio iof ithe irisk iof idisease iin ithe iexposed iindividual iis iconsidered ithe irelative irisk.
iAnother iway ithis iis isaid iis irelative irisk icould ibe ithe ilikelihood ior iprobability iof ideveloping ithe idisease iin
ithose iexposed icompared ito ithose inon-exposed, iso i….the iratio ibetween ithe itwo igroups.
Prospective iStudy: i Ask iyourself, iwhat iis ithe itime iframe? i Forward ior iback?
Controls: iSelection i/ isource iof icontrols i“Best ifriend icontrols” iAnother iapproach ito icontrol iselection iis
ito iuse ia ibest ifriend icontrol. iIn ithis iapproach, ia iperson iwho ihas ibeen iselected ias ia icase iis iasked ifor ithe
iname iof ia ibest ifriend iwho imay ibe imore ilikely ito iparticipate iin ithe istudy iknowing ithat ihis ior iher ibest
ifriend iis ialso iparticipating. iHowever, ithere iare ialso idisadvantages ito ithis imethod iof iselecting icontrols. iA
ibest ifriend icontrol iobtained iin ithis ifashion imay ibe isimilar ito ithe icase iin iage iand iin imany iother
idemographic iand isocial icharacteristics. iA iresulting iproblem imay ibe ithat ithe icontrols imay ibe itoo isimilar
