2019
Samenvatting MTB
BLOK 1
LOES KIEVITSBOSCH
, Epidemiologie 1
CONTENTS
Epidemiologie.......................................................................................................................................................... 4
Frequentiematen ................................................................................................................................................ 5
Plotselinge uitbraken .............................................................................................................................................. 9
Attack rate ........................................................................................................................................................... 9
Reproductiegetal ................................................................................................................................................. 9
Epidemische curve ............................................................................................................................................ 11
Onderzoeksopzet .................................................................................................................................................. 13
Onderzoeksdesigns ........................................................................................................................................... 14
Cohortonderzoek .......................................................................................................................................... 15
Patiënt-controleonderzoek ........................................................................................................................... 16
Cross-sectioneel onderzoek .............................................................................................................................. 18
Ecologisch onderzoek ........................................................................................................................................ 18
Proces randomized onderzoek .......................................................................................................................... 19
Frequentie ............................................................................................................................................................. 20
Associatiematen .................................................................................................................................................... 24
Betrouwbaarheid en validiteit .............................................................................................................................. 27
Betrouwbaarheid .............................................................................................................................................. 27
Reproduceerbaarheid ................................................................................................................................... 27
Validiteit ............................................................................................................................................................ 27
Interne validiteit ............................................................................................................................................ 27
Externe validiteit ........................................................................................................................................... 28
Toevallige fouten........................................................................................................................................... 29
Systematische fouten .................................................................................................................................... 29
Gouden standaard......................................................................................................................................... 29
Bias .................................................................................................................................................................... 30
Selectiebias ................................................................................................................................................... 30
Selectieve uitval ............................................................................................................................................ 32
Informatiebias ............................................................................................................................................... 32
Confounding .................................................................................................................................................. 33
Effectmodificatie ........................................................................................................................................... 34
Vertekening verhelpen ...................................................................................................................................... 34
Randomisatie ................................................................................................................................................ 35
Restrictie ....................................................................................................................................................... 35
Matchen ........................................................................................................................................................ 35
Standaardfout ............................................................................................................................................... 36
1
, Epidemiologie 2
Stratificatie .................................................................................................................................................... 37
Standaardisatie ............................................................................................................................................. 37
Schematische weergave confounding/effectmodificatie ................................................................................. 37
Multivariabele regressieanalyse ................................................................................................................... 37
Causale diagrammen ..................................................................................................................................... 38
Betrouwbaarheidsinterval ................................................................................................................................ 39
Etiologie en causaliteit .......................................................................................................................................... 41
Levels of evidence ............................................................................................................................................. 42
Preventie ........................................................................................................................................................... 42
Diagnostiek en prognostiek................................................................................................................................... 42
Soorten validiteit ............................................................................................................................................... 44
Maten ter kwantificatie van diagnostische tests .......................................................................................... 44
Likelihood ratio ................................................................................................................................................. 46
Likelihood ratio van een positieve testuitslag ............................................................................................... 46
Likelihood ratio van een negatieve testuitslag ............................................................................................. 46
Predictieve waarden ......................................................................................................................................... 47
Positieve predictieve waarde ........................................................................................................................ 47
Negatieve predictieve waarde ...................................................................................................................... 47
Testen combineren ........................................................................................................................................... 47
In serie geschakelde tests ............................................................................................................................. 47
Parallelle tests ............................................................................................................................................... 48
Inter- en intrabeoordelaarsovereenkomst ....................................................................................................... 48
Percentage overeenstemming ...................................................................................................................... 48
Cohen’s kappa ............................................................................................................................................... 48
Correlatiecoëfficiënt ..................................................................................................................................... 49
Verdeling van verschillen tussen beide metingen per individu .................................................................... 49
Intraklassecorrelatiecoëfficiënt voor overeenstemming .............................................................................. 49
Interventie............................................................................................................................................................. 50
Uitvoering interventieonderzoek ...................................................................................................................... 50
Vertroebeling van onderzoeksresultaten.......................................................................................................... 51
Stratificatie .................................................................................................................................................... 52
Designs .............................................................................................................................................................. 53
Bijwerkingen medicatie ..................................................................................................................................... 53
Hypothesen testen ................................................................................................................................................ 55
Type fouten ....................................................................................................................................................... 56
Type 2 fout .................................................................................................................................................... 56
Type 1 fout .................................................................................................................................................... 56
2
, Epidemiologie 3
Type 3 fout .................................................................................................................................................... 57
One-independant sample z-test........................................................................................................................ 57
Non-directional, tweezijdige toets .................................................................................................................... 57
Z-toets ........................................................................................................................................................... 58
Directional, eenzijdige toets ............................................................................................................................. 58
Lower-tail critical hypothesis test (H1:<) ...................................................................................................... 58
Effect size .......................................................................................................................................................... 58
Cohen’s d....................................................................................................................................................... 59
Power ................................................................................................................................................................ 59
T-toets ................................................................................................................................................................... 61
Geschatte standaardfout (SM) .......................................................................................................................... 61
Vrijheidsgraden (df) .......................................................................................................................................... 61
T-verdeling ........................................................................................................................................................ 61
Geschatte d → Effect size ................................................................................................................................. 62
Percentage variantie als gevolg van de behandeling (r²) → Effect size ............................................................ 62
Betrouwbaarheidsinterval (BI) .......................................................................................................................... 62
Onafhankelijke t-toets....................................................................................................................................... 63
Geschatte variantie (pooled variance s²P) ........................................................................................................ 64
Statistiek................................................................................................................................................................ 66
Samenvatting werkgroepopdrachten ............................................................................................................... 66
Standaardiseren waardes.............................................................................................................................. 66
Meetniveaus.................................................................................................................................................. 66
Binomiale kansverdeling ............................................................................................................................... 67
Normale kansverdeling ................................................................................................................................. 67
T-verdeling .................................................................................................................................................... 68
Kansberekening ................................................................................................................................................. 68
Rekenregels ................................................................................................................................................... 68
Confounding/effectmodificatie ..................................................................................................................... 70
Toevalsovereenkomst ................................................................................................................................... 71
Cohen’s kappa ............................................................................................................................................... 71
Bijlage 1: Hoorcollege 1......................................................................................................................................... 73
Bijlage 2: Hoorcollege 2......................................................................................................................................... 90
Bijlage 3: Hoorcollege 3......................................................................................................................................... 97
Bijlage 4: Hoorcollege 4....................................................................................................................................... 108
Bijlage 5: Hoorcollege 5....................................................................................................................................... 121
Bijlage 6: Hoorcollege 6....................................................................................................................................... 130
Bijlage 7: Hoorcollege 7....................................................................................................................................... 140
3
Samenvatting MTB
BLOK 1
LOES KIEVITSBOSCH
, Epidemiologie 1
CONTENTS
Epidemiologie.......................................................................................................................................................... 4
Frequentiematen ................................................................................................................................................ 5
Plotselinge uitbraken .............................................................................................................................................. 9
Attack rate ........................................................................................................................................................... 9
Reproductiegetal ................................................................................................................................................. 9
Epidemische curve ............................................................................................................................................ 11
Onderzoeksopzet .................................................................................................................................................. 13
Onderzoeksdesigns ........................................................................................................................................... 14
Cohortonderzoek .......................................................................................................................................... 15
Patiënt-controleonderzoek ........................................................................................................................... 16
Cross-sectioneel onderzoek .............................................................................................................................. 18
Ecologisch onderzoek ........................................................................................................................................ 18
Proces randomized onderzoek .......................................................................................................................... 19
Frequentie ............................................................................................................................................................. 20
Associatiematen .................................................................................................................................................... 24
Betrouwbaarheid en validiteit .............................................................................................................................. 27
Betrouwbaarheid .............................................................................................................................................. 27
Reproduceerbaarheid ................................................................................................................................... 27
Validiteit ............................................................................................................................................................ 27
Interne validiteit ............................................................................................................................................ 27
Externe validiteit ........................................................................................................................................... 28
Toevallige fouten........................................................................................................................................... 29
Systematische fouten .................................................................................................................................... 29
Gouden standaard......................................................................................................................................... 29
Bias .................................................................................................................................................................... 30
Selectiebias ................................................................................................................................................... 30
Selectieve uitval ............................................................................................................................................ 32
Informatiebias ............................................................................................................................................... 32
Confounding .................................................................................................................................................. 33
Effectmodificatie ........................................................................................................................................... 34
Vertekening verhelpen ...................................................................................................................................... 34
Randomisatie ................................................................................................................................................ 35
Restrictie ....................................................................................................................................................... 35
Matchen ........................................................................................................................................................ 35
Standaardfout ............................................................................................................................................... 36
1
, Epidemiologie 2
Stratificatie .................................................................................................................................................... 37
Standaardisatie ............................................................................................................................................. 37
Schematische weergave confounding/effectmodificatie ................................................................................. 37
Multivariabele regressieanalyse ................................................................................................................... 37
Causale diagrammen ..................................................................................................................................... 38
Betrouwbaarheidsinterval ................................................................................................................................ 39
Etiologie en causaliteit .......................................................................................................................................... 41
Levels of evidence ............................................................................................................................................. 42
Preventie ........................................................................................................................................................... 42
Diagnostiek en prognostiek................................................................................................................................... 42
Soorten validiteit ............................................................................................................................................... 44
Maten ter kwantificatie van diagnostische tests .......................................................................................... 44
Likelihood ratio ................................................................................................................................................. 46
Likelihood ratio van een positieve testuitslag ............................................................................................... 46
Likelihood ratio van een negatieve testuitslag ............................................................................................. 46
Predictieve waarden ......................................................................................................................................... 47
Positieve predictieve waarde ........................................................................................................................ 47
Negatieve predictieve waarde ...................................................................................................................... 47
Testen combineren ........................................................................................................................................... 47
In serie geschakelde tests ............................................................................................................................. 47
Parallelle tests ............................................................................................................................................... 48
Inter- en intrabeoordelaarsovereenkomst ....................................................................................................... 48
Percentage overeenstemming ...................................................................................................................... 48
Cohen’s kappa ............................................................................................................................................... 48
Correlatiecoëfficiënt ..................................................................................................................................... 49
Verdeling van verschillen tussen beide metingen per individu .................................................................... 49
Intraklassecorrelatiecoëfficiënt voor overeenstemming .............................................................................. 49
Interventie............................................................................................................................................................. 50
Uitvoering interventieonderzoek ...................................................................................................................... 50
Vertroebeling van onderzoeksresultaten.......................................................................................................... 51
Stratificatie .................................................................................................................................................... 52
Designs .............................................................................................................................................................. 53
Bijwerkingen medicatie ..................................................................................................................................... 53
Hypothesen testen ................................................................................................................................................ 55
Type fouten ....................................................................................................................................................... 56
Type 2 fout .................................................................................................................................................... 56
Type 1 fout .................................................................................................................................................... 56
2
, Epidemiologie 3
Type 3 fout .................................................................................................................................................... 57
One-independant sample z-test........................................................................................................................ 57
Non-directional, tweezijdige toets .................................................................................................................... 57
Z-toets ........................................................................................................................................................... 58
Directional, eenzijdige toets ............................................................................................................................. 58
Lower-tail critical hypothesis test (H1:<) ...................................................................................................... 58
Effect size .......................................................................................................................................................... 58
Cohen’s d....................................................................................................................................................... 59
Power ................................................................................................................................................................ 59
T-toets ................................................................................................................................................................... 61
Geschatte standaardfout (SM) .......................................................................................................................... 61
Vrijheidsgraden (df) .......................................................................................................................................... 61
T-verdeling ........................................................................................................................................................ 61
Geschatte d → Effect size ................................................................................................................................. 62
Percentage variantie als gevolg van de behandeling (r²) → Effect size ............................................................ 62
Betrouwbaarheidsinterval (BI) .......................................................................................................................... 62
Onafhankelijke t-toets....................................................................................................................................... 63
Geschatte variantie (pooled variance s²P) ........................................................................................................ 64
Statistiek................................................................................................................................................................ 66
Samenvatting werkgroepopdrachten ............................................................................................................... 66
Standaardiseren waardes.............................................................................................................................. 66
Meetniveaus.................................................................................................................................................. 66
Binomiale kansverdeling ............................................................................................................................... 67
Normale kansverdeling ................................................................................................................................. 67
T-verdeling .................................................................................................................................................... 68
Kansberekening ................................................................................................................................................. 68
Rekenregels ................................................................................................................................................... 68
Confounding/effectmodificatie ..................................................................................................................... 70
Toevalsovereenkomst ................................................................................................................................... 71
Cohen’s kappa ............................................................................................................................................... 71
Bijlage 1: Hoorcollege 1......................................................................................................................................... 73
Bijlage 2: Hoorcollege 2......................................................................................................................................... 90
Bijlage 3: Hoorcollege 3......................................................................................................................................... 97
Bijlage 4: Hoorcollege 4....................................................................................................................................... 108
Bijlage 5: Hoorcollege 5....................................................................................................................................... 121
Bijlage 6: Hoorcollege 6....................................................................................................................................... 130
Bijlage 7: Hoorcollege 7....................................................................................................................................... 140
3
