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Epidemiology Exam 2 > Interventional Studies > Flashcards

Interventional Studies Flashcards

1
Q

what methods are at the top of the pyramid?

A

systematic reviews

meta analyses

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2
Q

what method is at the very bottom of the pyramid?

A

in vitro research

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3
Q

list the evidence pyramid in order from lowest to highest

A 
in vitro
animal
case report
case series
ecological
cross-sectional
case-control
cohort
interventional
sys. reviews & meta
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4
Q

systematic reviews

A

compilation of multiple studies into one review

‘collective book report’

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5
Q

meta-analysis

A

compilation of the actual data of multiple studies

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6
Q

other names for interventional studies

A

clinical trial or study
experimental study
human study
investigational study

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7
Q

what are the key differences between observational and interventional studies?

A

forced allocation and ability to show causality in interventional studies

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8
Q

what 4 factors determine the phase of interventional study?

A
  1. purpose/focus
  2. study subjects
  3. sample size
  4. duration (disease specific)
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9
Q

as your phase number increases what also increases?

A

the studies duration and sample size

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10
Q

phase 0 and 1 are the only phases to include?

A

only logical places to include healthy subjects

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11
Q

in phase 4 you never see …..?

A

healthy subjects

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12
Q

describe ‘pre-clinical’ study

A

prior to human investigation

animal testing/study

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13
Q

what does phase 0 study?

A

exploratory or investigation of a new drug

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14
Q

phase 0 – list the 4 factors

A
  1. asses drug actions in a single/few doses
  2. typically healthy subjects (oncology)
  3. very small samples (typically <20)
  4. short duration (just long enough to monitor effects of the dose)
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15
Q

phase 1 – factors

A
  1. assess safety/how the body tolerates a drug
  2. healthy or diseased
  3. small 20 - 80 (<100)
  4. short duration - few weeks
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16
Q

what phases can represent first in human studies?

A

phase 0 or 1
or
phase 0 and 1 can be combined into one study

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17
Q

phase 2 – factors

A
  1. assess effectiveness of drug
  2. diseased
  3. large 100-300
  4. medium duration - weeks to months
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18
Q

in which phases do we assess effectiveness of a drug before it gains FDA approval?

A

phase 2 and 3

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19
Q

phase 3 – factors

A
  1. assess effectiveness
  2. diseased
  3. larger 500 - 3000
  4. long duration - months to year+
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20
Q

discuss phase 3 subjects

A

typically all diseased
may expand to have inclusion criteria to create different comparison groups

introduce different perspectives of null hypothesis
superior/equal/not worse

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21
Q

what is the final stage before FDA approval ?

A

phase 3

must do several phase 3 studies to show a greater ratio of positive to negative effects

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22
Q

generalize the purpose of phase 4

A

post-market study
FDA approval has already been gained and drug is on the market
study assesses the effect of the drug as it is used throughout the population
long term effects
co-morbidities

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23
Q

phase 4 – factors

A
  1. assess long-term safety and effectiveness
  2. diseased - those taking the drug
  3. entire population - hundreds to thousands
  4. varies - can be several years and ongoing
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24
Q

advantages of interventional studies?

A

can demonstrate causality

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25
Q

disadvantages of interventional studies

A

cost
time/complexity
ethics
validity

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26
Q

exploratory vs. explanatory studies

A

explore - looking at effectiveness, usefulness of a drug. non-real clinical environment. looking at how many doses or how big a dose to get effects

explain - interventional style
how to treat disease and patient
more real environment, flexibility to clinical, ability to change treatments

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27
Q

another term for explanatory studies

A

pragmatic studies

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28
Q

interventional study designs

A

simple or factorial

all studies are simple or factorial and parallel or cross-over

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29
Q

between simple and factorial, which requires more subjects?

A

factorial

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30
Q

describe simple design

A

divides subjects into x # of groups with only 1 round of randomization

used to test 1 hypothesis

no further division into groups

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31
Q

describe factorial design

A

divides subjects into >2 groups with at least 2 or more rounds of randomization to create subgroups

can test multiple hypotheses at once

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32
Q

major advantage of factorial design

A

-improves efficiency for answering clinical Q’s

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33
Q

characteristics of factorial design

A
  • bigger study population
  • increased complexity
  • increased risk of drop outs
  • possible restriction to validity
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34
Q

explain parallel studies

A

groups are simultaneously and exclusively studied

no switching between interventions is allowed

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35
Q

explain cross-over studies

A

subjects can serve as their own control by doing one intervention, wash-out phase
and then doing the other intervention

allowing between and w/in group comparisons

36
Q

pictorials of cross-over studies

A

there is always an arrow present showing mvt of subjects

37
Q

wash out

A

a period between cross-overs where the subjects go thru a time period to get the first intervention out of their system

this serves to eliminate contamination

38
Q

lead in

A

a period before the study even starts to clear the subjects system of anything they might have been doing in their normal lives

39
Q

what is the difference between washout and lead in phases?

A

lead in is always before the study begins and washout occurs when subjects are switching groups

40
Q

what are the other benefits of utilizing a lead in period?

A
  • gives subjects a practice period

- can observe the compliance and follow-up abilities of the subjects before the study actually starts

41
Q

another term for lead in phase

A

run-in period/phase

42
Q

disadvantages of cross-over design

A

-only good for long-term conditions that are not curable or the treatment only gives short-term relief

  • subjects must stick w/ study for longer duration
  • washout required
  • complex data analyses
43
Q

outcomes or endpoints in interventional studies

A
  • primary
  • secondary, tertiary, etc.
  • composite
44
Q

primary outcomes

A

the most important outcome

-answers the main research question

45
Q

secondary outcomes

A

lesser importance than primary

-possible for future hypothesis generation

46
Q

composite outcomes

A

combines multiple endpoints into one

can also be considered the primary outcome, with the individual endpoints being the secondary endpoints/outcomes

47
Q

POEMs

A

patient oriented endpoints—most clinically relevant

ex. death, stroke, MI, hospitalization, preventing dialysis

48
Q

DOEs

A

disease oriented endpoints—-elements used in place of evaluating POEMs
ex.
blood pressure for stroke risk
cholesterol for MI risk

49
Q

group allocation

A

random or non-random

50
Q

non-random group allocation

A

subjects do not have equal probability of being selected to each intervention group

51
Q

random group allocation

A

subjects have equal chance of begin assigned to every intervention group

52
Q

randomization - purpose

A

to make groups as equal as possible

based on known and unknown important factors/confounders

but group equality is never guaranteed

53
Q

randomization is used…..

A

in interventional studies only

observational studies do not use randomization

54
Q

examples of forms of randomization

A

simple
blocked
stratified

55
Q

simple randomization

A

equal probability for allocation within one of the study groups

56
Q

blocked randomization

A

ensures balance within each intervention group

best to ensure all groups are equal in size

57
Q

stratified randomization

A

ensures balance with known confounding variables

can also pre-select levels to be balanced within each confounder

58
Q

new term for confounder

A

interfering factors

59
Q

masking of study subjects and investigators

A

single blind
double blind
open-label

60
Q

single blind

A

masking
subjects are not informed of their intervention group

researchers do know

61
Q

double blind

A

masking

subjects and researchers do not know who belongs to which group

62
Q

open-label

A

unmasked/no blinding study

subjects and researchers know who is in what group

63
Q

what can be used to assess adequacy of blinding

A

post-hoc’s survey

64
Q

forms of blinding

A

placebo
placebo-effect
hawthorne-effect

65
Q

placebo therapy

A
  • -inert treatments made to look identical in all aspects to the actual treatment but has no real effects
    ex. dosage form, frequency, monitoring, therapy requirements
66
Q

double dummy

A

more than 1 placebo is used

67
Q

placebo effect

A

improvement in condition by power of suggestion of begin treated, can be as powerful as 30-50%

the positive benefits you get from knowing you could be getting a treatment but you are actually getting the placebo

68
Q

hawthorne-effect

A

study subjects change their behavior solely due to awareness of being studied/observed

69
Q

post-hoc subgroup analysis

A

data-dredging or fishing

reduces power of data and increases risk of type 2 error

70
Q

when is post-hoc accepted?f

A

not accepted when not planned

accepted when it is planned or performed for hypothesis generation

71
Q

sample size determination

A

always have excess in sample size to account for possible drop-outs, deaths, move-away, etc.

72
Q

managing drop-outs

A

either include them anyway or drop them

73
Q

intention to treat method

A

a study that includes data from drop-outs, anything missed is considered null or no benefit

74
Q

intention to treat results in

A
  • preserves randomization process
  • preserves baseline characteristics of groups
  • maintains statistical power of original sample size
75
Q

ignoring drop outs

A

include only compliant subjects in data analyses

must get a larger N to counteract but need drop out to be equal in groups

per-protocol or efficacy-analysis

76
Q

as-treated method

A

ignores group allocation
subjects can switch groups
subjects are evaluated in the group they move to, end in, or spend most time in

77
Q

per-protocol method

A

ignoring drop outs

78
Q

efficacy-analysis

A

only including compliant subjects in data, ignoring drop outs

79
Q

impact of per-protocol results

A
  • biases can effect
  • typically over estimates effects
  • reduces generalizability
80
Q

assessing adherence

A

ways in which the researchers know someone is complying with the rules
drug levels
pill counts
bottle tops

81
Q

methods of improving adherence

A

ways to increase the compliance of subjects
frequent communications or follow-ups
treatment alarms
dosage containers

82
Q

list the bottom 3 studies of the research evidence pyramid beginning with the least

A

in vitro
animal studies
case reports

83
Q

what is the top of the evidence pyramid

A

systematic reviews and meta-analyses

then interventional exploratory and pragmatic studies

84
Q

list the observational study types in order of high to low evidence

A 
cohort
case-control
cross-sectional
ecological
case series
case reports

animal research
in vitro

85
Q

of the following which has the least amount of evidence?

ecological
pragmatic studies
case series
case reports

A

case reports
case series
ecological
pragmatic

Epidemiology Exam 2 (6 decks)

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