U.S. Regulation of Drugs and Post-Marketing Surveillance Pt. 2 - Public Health & Policy

What is the basic aim of Analytical Designs?

How do they accomplish this?

Basic aim is to determine the presence of a Relationship (association) between Exposure and Outcome

They compare frequencies of effect in those who use the drug vs. those who do NOT use the drug

What are the two directions in which a population is followed in Populational Pursuit?

Briefly describe each pursuit direction.

1. PROSPECTIVE (DRUG --> EFFECT / OUTCOME)

- Assemble a group of people with the Exposure but without the Outcome

- Follow them FORWARD chronologically through time

2. RETROSPECTIVE (EFFECT / OUTCOME --> DRUG)

- Assemble a group of people with the Outcome

- Ascertain the Frequency of prior Exposure in REVERSE chronology

What is a Cohort (Prospective) Study?

What can it garner?

Observational study where a population (COHORT) free of the Outcome (EFFECT) at the start of the specified time period is selected based on their Exposure status to a particular drug

- Then followed over time to determine the development of the Outcome (EFFECT)

Can garner Incidence

What does Incidence =?

INCIDENCE = RISK

RISK = INCIDENCE

drill it into your head and slowly go insane

What are three other names for Cohort Studies?

Briefly describe why each name is used.

1. PROSPECTIVE

- Study population is followed from Exposure to Outcome

2. INCIDENCE

- Measures development of Outcome

3. LONGITUDINAL

- Study participants, once identified, are followed individually throughout the study period

What two factors are used to measure Association in Cohort Studies?

What do they represent?

1. FREQUENCY OF EFFECT IN THE EXPOSED

- Incidence (Risk) of Effect in the Exposed (Ie)

2. FREQUENCY OF EFFECT IN THE UNEXPOSED

- Incidence (Risk) of Effect in the Non-Exposed (Ine)

What is Relative Risk (RR) a comparison of?

Comparison of Incidence (Risk) of Effect in the Exposed (Ie) and the Non-Exposed (Ine)

RR = Ie / Ine

What is the interpretation of Relative Risk (RR)?

The risk of developing (insert thing) in those who were exposed is ___ times higher than the risk of developing (insert thing) in those who were not exposed

THERE IS A RELATIONSHIP / ASSOCIATION BETWEEN (EXPOSURE) AND OCCURENCE OF (INSERT THING)

What does a Relative Risk (RR) of 1 mean?

What does a statistical test determine in this case?

Frequency of the Effect is the same in those exposed vs. those not exposed, OR

There is NO relationship / association between exposure and effect

Statistical test determines if RR is significantly different from 1

What are the advantages of Cohort Studies?

Disadvantages?

ADVANTAGES:

- Establishment of a Temporal relationship

- Calculate Incidence and Relative Risk

- Useful for studying rare exposures

DISADVANTAGES:

- Requires large sample size

- Expensive and can take a long time

What is a Case-Control (Retrospective) Study?

Compares cases (with effect) to controls (without effect) to look for differences in Antecedent exposures (drug)

What can Case-Control (Retrospective) Studies NOT measure?

What do they compare?

Cannot measure Incidence due to effect having already developed

Compare the odds of being exposed between cases and controls

What are Odds in relation to Case-Control Studies?

What is the equation for determining Odds of an Event Occurrence?

Odds are ratios of proportions

Odds of Event Occurrence = Proportion of People Experiencing Event / Proportion of People Not Experiencing Event

What does an Odds Ratio compare?

Give the equation for Odds Ratio.

Compares Odds of being Exposed between Cases and Controls

Odds Ratio = A / B

What does A represent in relation to Odds Ratio?

B?

A = Prop. who are Exposed among Cases / Prop. who are Not Exposed among Cases

B = Prop. who are Exposed among Controls / Prop. who are Not Exposed among Controls

What is the interpretation of Odds Ratio?

What does an Odds Ratio (OR) = 1 mean?

Individuals with Case were ___ times more likely to have been exposed to (Exposure) than Controls

If OR = 1, Odds of individuals who were exposed to (Exposure) are the same amongst those in Case and in Control

- Implies the drug is NOT the issue here

What are two other names for Case-Control Studies?

Briefly describe why each name is used.

1. RETROSPECTIVE

- Study populations are followed from Outcome backward to Exposure or No Exposure

- Chronologically backwards

2. TROHOC

- Cohort spelled backwards....

What are the main advantages of Case-Control Studies?

Disadvantages?

ADVANTAGES:

- Study of rare Outcomes / effects (guarantees sufficient number of cases)

- Can study multiple possible Exposures of an effect using the same number of Cases and Controls

- Less costly and less time-consuming

DISADVANTAGES:

- Temporal association is difficult to determine

- Cannot calculate Incidence or Relative Risk

- Recall Bias when ascertaining Exposure

What are two uses of Pharmacoepidemiology?

1. Complements information from Pre-Marketing studies (Clinical Trials)

2. Develops new types of information not available from Pre-Marketing Studies