Lecture 15 9/23/24 Flashcards

1
Q

What is the purpose of descriptive studies?

A

summarize clinical features and characteristics of a series of cases observed in clinical settings or in the population

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2
Q

What is the conceptual design of descriptive studies?

A

record and point out unique features and commonalities of a series of cases

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3
Q

What is measured in a descriptive study?

A

-frequency of diseases and a descriptive account of disease entity
-does NOT explain risk factors that may be associated with the illness or death

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4
Q

What are the strengths of descriptive studies?

A

-relatively inexpensive
-can be accomplished in a short time

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5
Q

What is the limitation of descriptive studies?

A

no associations can be made

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6
Q

What are the characteristics of a case report?

A

-detailed presentation of a single case
-generally not representative of the general course of disease

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7
Q

What are the characteristics of a case series?

A

-collection of cases
-useful in hypothesis generation

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8
Q

What is provided by a survey?

A

data about the frequency and distribution of a disease in a specified population

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9
Q

What is the purpose of a cohort study?

A

-to determine incidence rate; rate at which healthy subjects in a given population become sick
-to determine risk rate/ratio; probability of a subject developing a disease following an exposure to risk factors

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10
Q

What are the strengths of a cohort study?

A

-can examine multiple effects of a single exposure
-can clarify temporal relationship between exposure and disease
-allows direct measurement of incidence of disease in the exposed vs. non-exposed groups
-ideal for evaluation of rare exposures

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11
Q

What are the limitations of a cohort study?

A

-inefficient for evaluation of rare outcomes
-can be extremely expensive and time consuming
-validity of results can be affected by losses to follow-up

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12
Q

What is the purpose of a cross-sectional study?

A

-estimate the prevalence of an infection/disease in a population at a point in time or given time period
-make association between set of risk factors and prevalence of infection/disease

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13
Q

What is the conceptual design of a cross-sectional study?

A

data relating to the disease status and risk factors that may be associated with disease are measured simultaneously

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14
Q

What is measured by a cross-sectional study?

A

-prevalence of infection/disease
-association between disease and risk factors

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15
Q

How is rate ratio of disease calculated?

A

prevalence of disease among exposed/prevalence of disease among non-exposed

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16
Q

How is rate ratio of exposure calculated?

A

prevalence of exposure among diseased/prevalence of exposure among non-diseased

17
Q

What is an odds ratio?

A

-ratio of two odds
-odds of disease among exposed/odds of disease among non-exposed
-odds of exposure among diseased/odds of exposure among non-diseased
-can be calculated as AxD/BxC

18
Q

What are the strengths of a cross-sectional study?

A

-inexpensive and quick
-examine multiple associations for a single disease

19
Q

What are the limitations of a cross-sectional study?

A

-difficult to establish temporal relationships between exposure and disease outcome
-cannot measure incidence or risk of disease directly

20
Q

What is the purpose of a case-control study?

A

determine if some exposures in the past are likely to have been associated with the occurrence of clinical illnesses/deaths being observed

21
Q

What is measured by a case-control study?

A

odds ratio; odds that a case was exposed/odds that a control was exposed

22
Q

What are the strengths of a case-control study?

A

-quick and inexpensive
-suited for eval. of diseases with long latent periods
-optimal for eval. or rare diseases
-can examine multiple etiologic factors for a single disease

23
Q

What are the limitations of a case-control study?

A

-difficult to directly compute incidence rates of disease in exposed and non-exposed individuals
-temporal relationship between exposure and disease may be difficult to establish
-particularly prone to bias

24
Q

How do cohort studies compare to case-control studies and cross-sectional studies?

A

-cohort studies begin by looking at exposures and following for the outcomes
-case-control studies start with outcomes and determine potential exposures retroactively
-cross-sectional studies look at exposures and outcomes simultaneously