Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

epidemiology (WOODS) > test 2 > Flashcards

test 2 Flashcards

1
Q

what are the types of research in increasing strength of evidence

A

in vitro (test-tube) research, animal research, case reports, case series, ecological, cross-sectional, case control cohort

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is study design selection based on

A 
hypothesis
randomization
ethics of methodology
efficiency & practicality
costs
validity of acquired information (internal and external)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the difference between type 1 and type 2 error

A

type one is when you have a false positive

type 2 is when you get a false negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are observational studies

A

study design considered natural. researchers observe subject elements occurring naturally or selected by the individual (most not able to prove causation)
there is NO researcher-forced group allocation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are interventional study designs

A

considered experimental. investigator-selections intervention/exposure
there IS researcher-forced group allocation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are examples of interventional study designs

A

pre-clinical, analytic studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are examples of observational study designs

A

cases (reports/series), ecological, cross-sectional, case-control, cohort

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

define equipoise

A

genuine confidence that an intervention may be worthwhile (risk vs benefit) in order to use it in humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the 4 principles of bioethics

A

autonomy, beneficence, justice, nonmaleficence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

define autonomy

A

self-rule/ self-determination. participants must:
have full and complete understanding of risks and benefits
decide for ones-self, without outside influences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

define beneficence

A

to benefit, or do good for, the patient (not society)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

define justice

A

equal and fair treatment regardless of patient characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

nonmaleficence

A

do no harm. researchers must not:

  • withhold info
  • provide false info
  • exhibit professional incompetence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the 3 main guidelines for human studies

A
  • respect for persons (research should be voluntary, subjects autonomous)
  • beneficence (research risks are justified by potential benefits)
  • justice (risks and benefits of the research are equally distorted)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

define consent

A

agreement to participate, based on being fully and completely informed (given by mentally-capable individuals of legal age)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

define assent

A

agreement to participate, based on being fully and completely informed, given by mentally-capable individuals not able to give legal consent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the IRB and what are its duties

A

institutional review board (ethics committee)
role is to project human subjects from undue risk (research not complying with principles of bioethics)
all human subject studies must be reviewed by an IRB prior to study initiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

who decides the laws and regulations that the IRB must follow

A

DHHS: department of health and human serves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the rules followed by the IRB called

A

Common Federal Rules (CFR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the agency that administers and enforces the regulations that the IRB must follow

A

the office of human research protections (OHRP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are the levels of IRB review and what do they entail

A
  • full board: used for ALL interventional trials with more than minimal/no risk to patients (all medication-related studies)
  • expedited: minimal risk and/or no patient identifiers
  • exempt: no patient identifiers, low/no risk, de-identified dataset analysis (environmental studies, use of existing data/specimens (de-identified))
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the DSMB and what do they do

A

Data safety & monitoring Board

  • semi-independent committee not involved with the conduct of the study but charged with reviewing study data as study professes, to assess for undue risk or benefit
  • pre-determined review periods
  • can stop study early, for either overly-positive or overly-negative findings
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the main difference between interventional study designs and observational

A

in interventional, investigator selects interventions and allocates study subjects to forced-intervention groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what observational studies are considered analytical

A

cross-sectional, case-control, cohort

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are characteristics of phase 1 studies

A

small sample size
short
main focus: safety
could use healthy individuals or those with the disease of interest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what are characteristics of phase 2 studies

A 
middle sample size (100-300_
commonly utilized with condition of interest
assessing efficacy in diseased pop
short-to-medium duration
likely to have narrow inclusion criteria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what are characteristics of phase 3 studies

A

larger sample size (1000-3000)
used in patients with condition of interest
long duration (many months to year or longer)
superiority vs non-inferiority vs equivalency
assesses efficacy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are characteristics of phase 4 studies

A

post marketing
long term effects (risk and benefits)/safety
very large population (more inclusive)
required for FDA approval

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are the main advantages of interventional studies

A

cause precedes effect (shows causation)

only design used for FDA for approval process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what are main disadvantages of interventional studies

A 
cost
complexity/time
ethical considerations
generalizability (external validity)
are methodology/findings applicable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are differences between explanatory and pragmatic interventional studies

A

explanatory: set dosage/prediscribed, more control
pragmatic: less controlled, more clinically relevant (can change dosage based on patient)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

define simply interventional study design

A

divides (randomizes) subjects exclusively into 2+ groups (single randomization process; no subsequent randomization divisions)
commonly used to test single hypothesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

define factorial interventional study design

A

divides subjects into 2+ groups and then further additionally sub-divides (randomizes) each of the groups into 2+ groups
used to test multiple hypotheses at same time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

define parallel interventional study design

A

groups simultaneously and exclusively managed
no switching of interventions after initial randomization
simple and factorial are also parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

define cross-over design of interventional studies

A

self-control studies
groups serve as their own control by crossing over from one intervention to another during the study
allows for smaller total N
allows for between and within group comparison

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

why is a washout period used

A

to get rid of any other confounding variables and to get the participant back to baseline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

how would you describe a lead-in phase

A

used to test for compliance. make sure that the person will be able to complete the requirements of the study (or at least predict if they will be able to)
can also be used as a washout phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what are some disadvantages of cross over design of interventional studies

A

*only suitable for long-term conditions which are not curable or which treatment provides short-term relief
*duration of study for each subject is longer
*carry over effects during cross over (wash out required)
*environment can have effects
complexity in data analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what is the difference between primary, secondary/tertiary, and composite outcomes/endpoints

A

primary: most important, key outcomes (main research question used for developing/conducting study
secondary/tertiary: lesser importance but still valuable, possible for future hypothesis generation
composite: combines multiple endpoints into a single outcome (could be considered primary outcome, and if so, then secondary outcomes may be the individual outcome elements from composite)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what is the difference between non-random and random group allocation/sample selection

A

non-random: subjects do not have equal probability of being selected or assigned to each interventional group (convenience sampling)
random: subjects do have equal probability of being assigned to each intervention group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

explain the different forms of randomization

A

simple: probability for allocation within one of the study groups
blocked: ensures balance within each intervention group (used when researcher wants to assure that all groups are equal in size)
stratified: ensures balance with known confounding variables (can also pre-select levels to be balanced within each interfering factor-confounder)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

define the different types of masking

A

single-blind: study subjects are not informed which intervention they are receiving (but clinicians/researchers are)
double blind: neither investigators nor study subjects are informed which intervention each subject is receiving
open label: everyone knows which intervention each subject is receiving

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what can be used to assess adequacy of blinding

A

post-hoc survey

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what are the different forms of blinding

A

placebo (dummy); inert treatments made to look identical in all aspects to the active treatments
placebo effect: improvement in condition: by power of suggestion and due to the care being provided
hawthorne-effect: desire of study subject to please investigators by reporting positive results (improvement), regardless of treatment allocation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

explain intent-to-treat

A
  • more conservative decision to use for drop outs/lost to follow-up
  • either use last known assessment and use that data for all following visits or use the person’s baseline as their values (no effect)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what does intent-to-treat result in

A

preserves randomization process
preserves baseline characteristics and group balance at baseline which controls for known and unknown confounders
maintains statistical power (original sample size)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

how can it be deemed appropriate to ignore individuals that drop out in interventional study

A

using pre-protocol or efficacy analysis: must comply for certain predetermined amount of study or their data is not included at all

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what does it mean to treat someone “as treated” in interventional studies when managing for drop outs/lost to follow up

A

ignore group assignments

allow subjects to switch groups and be evaluated in group they ended up in or stayed in longest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what is the major down fall of using pre-protocol in drop out decision in interventional studies

A

bias estimates of effect (commonly over-estimates effects) which reduces generalizability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

what are ways to improve adherence (compliance)

A

frequent followup visits/communications
treatment alarms/notifications
medication blister packs or dosage containers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

define equipoise

A

state of mind characterized by a legitimate uncertainty or indecision as to choice or course of action: there is implied/presumed benefit from the study that is occurring and that makes it worth completing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what are some ways to assess adherence (compliance)

A

drug level (multiple useful sites)
pill counts at each visit
bottle counter-tops

53
Q

define case-control studies

A

observational, analytical studies allowing researcher to be a passive observer of natural events occurring in individuals with the disease/condition of interest (cases) who are compared with people who do not have the condition of interest (controls)

54
Q

what are group assignments based on in case-control studies

A

disease status (outcome)

55
Q

what does the control group in case-control studies supply information about

A

the expected baseline risk-factor profile in the population from which the cases are drawn

56
Q

when are case-control studies particularly useful

A 
when studying a rare disease or investigating an outbreak
it is not possible to randomize
limited resources (time/money/subjects)
57
Q

sources for selection of controls in case-control studies

A

institutional/organization/provider: illnesses of controls should be unrelated to exposure being studied
spouses/relatives/friends: genetic, environmental, socio-economical, etc. similarities

58
Q

describe case-cross over design

A
  • subjects are their own controls during the other times that they do not have their acute change in risk
  • the only case-control study design able to adequately attempt to address the issue of temporality
59
Q

define nested case-control studies

A

case control studies conducted after, or out of, a prospective cohort study

60
Q

describe the types of sampling used in nested case-control studies

A

survivor sampling: sample of non-diseased individuals (survivors) at end of study period
base sampling: sample of non-diseased individuals at start of study period
risk-set sampling: sample of non-diseased individuals during study period at same time when case was diagnosed

61
Q

define recall bias

A

related to the amount/specificity that cases or controls recall past events differently
(usually cases are more likely to recall past exposures and levels of exposure)

62
Q

explain individual and group matching

A

individual: matches individuals based on specific patient-based characteristics, used when each case has unique and important characteristics
group: proportion of cases and proportion of controls with identical characteristics are matched, requires cases to be selected first

63
Q

what can be accomplished with analytical studies

A

we can compare groups and create statistical measures of association in those comparisons

64
Q

define cohort studies

A

observational, analytical studies allowing researcher to be passive observer of natural events occurring in naturally-exposed and unexposed (comparison) groups

65
Q

what is group allocation based on in cohort study designs

A

based on exposure status or group membership (something in common)

66
Q

when are cohort studies most valuable

A
  • when unable to randomize
  • limited resources (time/money/subjects)
  • exposure of interest is rare in occurrence and little is known about its associations/outcomes
  • when more interested in incidence rates/predictors of or risks for outcome of interest (more than effects of interventions)
67
Q

define prospective cohort studies

A

exposure group is selected on the basis of a past or current exposure and both groups (exposure and non-exposure) followed into the future to assess for outcomes of interest (which has yet to occur), and the compared

68
Q

define retrospective cohort studies

A

at the start of the study, both the exposure and the outcome of interest have occurred

69
Q

define ambidirectional cohort study

A

uses retrospective design to assess past differences but adds all data collected on additional outcomes prospectively from start of study (looking for outcomes in the past and into the future)

70
Q

define cohort

A

group with someone in common

71
Q

define birth cohort

A

individuals assembled based on being born in a geographic region in a given time period

72
Q

define inception cohort

A

individuals assembled at a given point based on some common factor (where people live or where they work, or something they have in common)
*selected on being a stable population with updated annual population lists, and other unique attributes

73
Q

define exposure cohort

A

individuals assembled based on some common exposure (frequency connected to environmental or other one-time events)

74
Q

define fixed cohort

A

a cohort (derived from an irrevocable event) which can’t gain members but can have loss-to-follow-ups

75
Q

define closed cohort

A

a fixed cohort with no loss-to-follow-up

76
Q

define open (dynamic) cohort

A

a cohort with new additions and some loss-to-follow-ups (cohort can increase or decrease over time)

77
Q

how are the exposed study group decided

A

allocate subject based on pre-defined criteria of “exposure”

78
Q

how is an unexposed study population chosen internally

A
  • patients from the same “cohort”, yet who are unexposed

* if there are only levels of exposure, you may have to use the lowest exposure group as comparator

79
Q

how is an unexposed study population chosen in the general population

A

used as a second choice when the best-possible comparison group (internal) is not realistically possible (i.e.: everyone is exposed; or the exposure subjects drawn from the general population)

80
Q

how is an unexposed study population chosen in a comparison cohort

A
  • this is the least acceptable group (but still can be utilized)
  • simply attempt to match group as close as possible on numerous personal characteristics (can’t control for other potentially harmful exposures in comparison cohort)
81
Q

what is the one type of observational study that can address temporality

A

prospective cohort

82
Q

what are the advantages of prospective cohort studies

A
  • can obtain a greater amount of study-important info from patients
  • follow-up/tracking of patients may be easier
  • better at giving answer to temporality
  • may look at multiple outcomes from a supposed single exposure
  • can calculate incidence & incidence rate
83
Q

disadvantages of prospective cohort studies

A
  • time, expense & lost-to-follow-up
  • not efficient for rare diseases
  • not suited for long induction/latency conditions
  • exposure (or its amount) may change over time
84
Q

what are the effects of loss to follow up on Cohort studies

A
  • possible with prospective cohorts
  • lowers sample size (power) (increased risk of Type 2 error, loss of study participation (follow-up) may not be equal between groups)
85
Q

advantages of retrospective cohort studies

A
  • best for long induction/latency conditions
  • able to study rare exposures
  • useful in the data already exists
  • saves time and money compared to prospective studies
86
Q

disadvantages of retrospective cohort studies

A
  • requires access to charts, databases, employment records
  • info may not factor in or control for other exposures to harmful elements
  • patients may not be available for interview if contact necessary for missing or incomplete data
  • exposure (or its amount) may have changed over time
87
Q

issues affecting outcome occurrence in groups for cohort studies

A

level of exposure (stratify)
induction period
latency period

88
Q

define induction period

A

interval between exposure which causes disease and onset of disease-process

89
Q

define latency period

A

interval between disease-process onset&clinical diagnosis and disease

90
Q

define healthy worker effect

A

if healthy, you work (even if exposed). if too ill to work (due to exposure). you may be unemployed (now part of non-working general population)

91
Q

define selection bias

A

how exposure status is defined/determined (less of an issue with exposure status)

92
Q

define cross-sectional studies

A

observational, descriptive/analytical studies that examine relationships of health/disease to other variables of interest at the same time

93
Q

what is another name for cross-sectional studies

A

prevalence studies

94
Q

what is the study group of a cross-sectional study

A

entire population or subset

95
Q

why are cross-sectional studies called this

A

because information gathered represent what is occurring at a point in time or time-frame a cross a population (snap shot in time)

96
Q

what are cross-sectional studies useful for

A

determining prevalence of a disease and risk factors across the pop
measuring current health status and planning for health services across the population
evaluating differences in subgroups within the population

97
Q

what are the main disadvantages of cross-sectional studies

A

prevalent cases may represent survivors
difficult to study diseases of low frequency
problems in determining temporal relationship of a presumed cause and effect

98
Q

what are the 2 cross-sectional approaches

A
  1. collect data on each member of the population

2. take a sample of the population and draw inferences to the remainder

99
Q

define probability samples

A

every element in the population has a known probability of being included in the sample

100
Q

what are the 3 main probability schemes of sampling for cross-sectional studies

A

simple random: obtain a list of population names and assign numbers to names and use random number generator to select names
stratified random: mutually exclusive categories, divide pop into relevant subgroups
systematic/convenience: decide on what fraction of pop is to be sampled and how they will be sampled

101
Q

what are the 2 major approaches to collection of new information in cross sectional studies

A

questionnaires/surveys

physical examination

102
Q

what does NHANES do

A

assesses the health and nutritional status of adults and children
combines interviews and physical examinations
survey sample is selected to represent the US population of all ages
travel around in 18 wheelers

103
Q

what does NHIS do

A

principle source of info on health of the civilian, non-institutionalized population
survey sample is selected to represent the US pop of all ages
data is collected through personal household interview
consists of a set of core questions that remain largely unchanged and a set of supplements used to respond to public health data needs as they arise

104
Q

what is NAMCS

A

national survey designed to meet the needs for objective, reliable information about the provision and use of ambulatory medical care serves in the U.S
based on a sample of visits to non-federal, office based physician primarily engaged in direct patient care

105
Q

what is NHCS

A

combined national survey designed to describe the national patterns of healthcare delivery in non-federal hospital based settings
*discharges from inpatient departments and institutions, visits to emergency departments, outpatient departments and ambulatory surgery centers

106
Q

what 3 previous cross-sectional surveys are integrated into NHCS

A

NHDS, NHAMCS, DAWN

107
Q

what is BRFSS

A

state-based system of telephone health surveys that collect info on health risk behaviors, preventive health practices, and healthcare access primarily related to chronic disease and injury

108
Q

define true positive

A

the screening test was positive and you actually do have the disease (test got it right)

109
Q

define true negative

A

the screening test was negative and you actually do not have the disease (the test got it right)

110
Q

define false positive

A

the test comes back positive, but you do not have disease (test got it wrong)

111
Q

define false negative

A

the test comes back negative, but you actually have the disease (test got it wrong)

112
Q

define sensitivity

A

how well a test can detect presence of disease when in fact disease is present (positivity of test n the diseased)

proportion of time that a test is positive in a patient that does have the disease

113
Q

what is the equation for sensitivity

A

sensitivity: TP/ (TP + FN) X 100%

TP/ (all diseased) X 100%

114
Q

define specificity

A

how well a test can detect absence of disease when in fact the disease is absent

proportion of time that a test is negative in a patient that does not have the disease

115
Q

what is the equation for specificity

A

TN/ (TN+FP) X 100%

TN/ (all not exposed) X 100%

116
Q

define positive predictive value (PPV)

A

how accurately a positive test predicts the presence of disease

Percentages of TP’s in patients with a positive test (correct prediction)

117
Q

what is the equation for PPV

A

TP/ (TP+FP) X 100%

TP/ (all positive tests) X 100%

118
Q

define negative predictive value (NPV)

A

how accurately a negative test predicts the absence of disease

percentage of TN’s in patients with a negative test (correct prediction)

119
Q

what is the equation for NPV

A

TN/ (TN+FN) X 100%

TN/ (all negative tests) X 100%

120
Q

define diagnostic accuracy/ diagnostic precision

A

(TP+TN)/ (TP+FP+FN+TN) X 100%

(TP+TN)/ (all patients) X 100%

121
Q

define likelihood ratio +

A

probability of a positive test in the presence of disease divided by probability of a positive test in the absence of disease

122
Q

what is the equation for LR+

A

sensitivity/ (1-specificity)

[(A/(A+C))/(B/(B+D))]

123
Q

what is the equation for LR-

A

(1-sensitivity)/Specificity

[C/(A+C))/ (D/ (B+D))]

124
Q

define receiver operator curves (ROC)

A

more efficient way to show a relationship between sensitivity and specificity for tests with numerical (continuous) outcomes

125
Q

define validity

A

ability to accurately discern between those that do and those that do not have the disease

126
Q

define internal validity

A

extent to which results accurately reflect what was being assessed (true situation of study population)

127
Q

define external validity

A

extent to which results are applicable to other populations (not included in the original study; also known as generalizability)

128
Q

define reliability

A

ability of a test to give the same result on repeated uses

epidemiology (WOODS) (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions