Pharmacology Case Reports

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Questions and Answers

What is one of the advantages of case-control studies?

They can study the outcome of a disease over time

They are inexpensive and can be conducted quickly (correct)

They can investigate only one variable at a time

They can be used to study rare diseases

What is a critical assumption in case-control studies?

That the outcome of the disease is known

That the exposure is always present

That controls are representative of the general population that does not have the disease (correct)

That cases are selected to be representative of those who do not have the disease

What is a disadvantage of case-control studies?

They can only be used to study rare diseases

They are susceptible to bias (correct)

They can only investigate one variable at a time

They are too expensive to conduct

What is a use of case-control studies?

To generate hypotheses about the causes of a new outbreak of disease Signup and view all the answers

What type of study follows a defined population over time?

Cohort study Signup and view all the answers

Why are case-control studies useful for studying rare diseases?

Because they are the only practical way to study rare diseases Signup and view all the answers

What is a limitation of case-control studies?

They are susceptible to bias Signup and view all the answers

What is a difference between case-control studies and cohort studies?

Case-control studies are retrospective, while cohort studies are prospective Signup and view all the answers

What is the major difference between cohort and case-control studies?

The basis of patient recruitment Signup and view all the answers

What is a major advantage of cohort studies over case-control studies?

They are free from the problem of selecting an undiseased control group Signup and view all the answers

When are cohort studies particularly useful?

When studying multiple possible outcomes from a single exposure Signup and view all the answers

What is an advantage of prospective cohort design?

It is a powerful strategy for assessing incidence Signup and view all the answers

What is a disadvantage of cohort studies?

They can require extremely large sample sizes to study relatively uncommon outcomes Signup and view all the answers

What is a limitation of retrospective cohort studies?

They are less costly and time-consuming Signup and view all the answers

What is a potential problem with prospective cohort studies?

They can require a prolonged time period to study delayed drug effects Signup and view all the answers

Why are cohort studies useful in postmarketing drug surveillance studies?

Because they are useful for studying multiple possible outcomes from a single exposure Signup and view all the answers

What was the concern about cimetidine after metiamide was withdrawn?

It would cause agranulocytosis Signup and view all the answers

What is a limitation of case series in determining causation?

They lack a control group Signup and view all the answers

What is an advantage of case reports and case series?

They provide clinical descriptions of a disease Signup and view all the answers

What is examined in analyses of secular trends?

Trends in an exposure and a disease over time or across geographic boundaries Signup and view all the answers

What is a characteristic of ecological studies?

They use data from entire populations Signup and view all the answers

What is an example of a type of study that analyzes data from a single region and examines how the trend changes over time?

Analysis of secular trends Signup and view all the answers

What is a disadvantage of case reports and case series?

They do not provide explanation other than conjecture Signup and view all the answers

What is the purpose of examining trends in an exposure and a disease over time or across geographic boundaries?

To test whether the trends coincide Signup and view all the answers

What is a case report typically used for in pharmacovigilance?

To raise hypotheses about drug effects and guide further studies Signup and view all the answers

What is an exception to the general rule that a case report cannot be used to make a statement about causation?

When the outcome is very rare and characteristic of the exposure Signup and view all the answers

What is the major strength of a randomized clinical trial?

Random assignment Signup and view all the answers

What is a case series?

A collection of patients with a single exposure, whose clinical outcomes are evaluated Signup and view all the answers

What is the main reason why associations demonstrated in randomized clinical trials are more likely to be causal associations?

Because they use random assignment Signup and view all the answers

What is a common limitation of case reports?

One cannot determine whether the adverse outcome was due to the drug exposure or would have happened anyway Signup and view all the answers

What is the primary purpose of randomization in a randomized clinical trial?

To minimize confounding variables Signup and view all the answers

What is an example of a case series?

100 consecutive women under the age of 50 who suffered from a pulmonary embolism and were taking oral contraceptives Signup and view all the answers

What is the primary purpose of a case series after drug marketing?

To quantify the incidence of an adverse reaction Signup and view all the answers

What is the purpose of a control group in a randomized clinical trial?

To compare the outcomes of the intervention group Signup and view all the answers

What is an example of a postmarketing surveillance study?

A study designed to quantify the incidence of an adverse reaction Signup and view all the answers

What type of question can be answered by a randomized clinical trial?

Is this drug better than placebo or the current established treatment? Signup and view all the answers

What is the purpose of stratification in a randomized clinical trial?

To minimize bias by controlling for confounding variables Signup and view all the answers

What is the main difference between a case report and a case series?

The number of patients involved Signup and view all the answers

What is the primary advantage of using a randomized clinical trial design?

It minimizes bias through randomization Signup and view all the answers

What is the purpose of an intervention group in a randomized clinical trial?

To receive the new intervention or treatment Signup and view all the answers

Study Notes

Case Reports

Describe a single patient who was exposed to a drug and experienced a particular outcome, usually adverse.
Useful for raising hypotheses about drug effects, but cannot determine whether the adverse outcome was due to the drug exposure or would have happened anyway.

Case Series

A collection of patients with a single exposure, whose clinical outcomes are evaluated and described.
Can also be a collection of patients with a single outcome, looking at their antecedent exposures.
Useful for quantifying the incidence of an adverse reaction and being certain that any particular adverse effect of concern does not occur in a larger population than studied prior to drug marketing.

Advantages and Disadvantages of Case Reports and Case Series

Advantages: Hypotheses are formed, easy to perform, and inexpensive.
Disadvantages: Does not provide explanation other than conjecture and does not establish causality or association.

Analyses of Secular Trends (Ecological Studies)

Examine trends in an exposure that is a presumed cause and trends in a disease that is a presumed effect and test whether the trends coincide.
Can be examined over time or across geographic boundaries.

Case-Control Studies

Useful for studying rare diseases or diseases that take long periods to develop.
Critical assumptions to minimize bias:
- Cases are representative of those who have the disease.
- Controls are representative of the general population that does not have the disease and are as identical as possible to the cases, minus the presence of the disease.
- Information is collected from cases and controls in the same way.
Advantages:
- Inexpensive and can be conducted quickly.
- Allows investigation of several possible exposures or associations.
Disadvantages:
- Confounding must be controlled.
- Only one outcome can be studied.
- Susceptible to bias.

Cohort Studies

Identify subsets of a defined population and follow them over time, looking for differences in their outcome.
Advantages:
- Free of the problem of selecting an undiseased control group.
- Prospective cohort studies are free of the problem of the questionable validity of retrospectively collected data.
- Particularly useful when studying multiple possible outcomes from a single exposure, especially a relatively uncommon exposure.
Disadvantages:
- Can require extremely large sample sizes to study relatively uncommon outcomes.
- Inefficiency for studying rare outcomes.
- Prospective cohort studies can require a prolonged time period to study delayed drug effects.

Randomized Clinical Trials (RCTs)

Participants are randomly allocated to either one intervention or another.
Each group is followed up for a specified period of time.
Analyzed in terms of specific outcomes defined at the start of the study.
Two groups should be identical as possible, with the only difference being the intervention.
Advantages:
- Allows assessment of causality.
- Minimizes bias through randomization and/or stratification.
- Questions that can be answered by a RCT:
  - Is this drug better than placebo or the current established treatment?
  - Is this new surgical procedure better than current practice?
  - Is a leaflet better than verbal advice in helping patients make informed choices about treatment options?
  - Is this new service better than the usual service?

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Description

A quiz about case reports in pharmacology, exploring their role in identifying adverse drug effects and raising hypotheses.