Pharmacoeipdemiology Flashcards
Epidemiology : Definition
the study of factors that determine the occurrence and distribution of diseases in populations.
Pharmacoepidemiology: Definition
the study of the use and effects of drugs in large numbers of people
Pharmacoepidemiologist combine pharmacology and epidemiology, to study the use and effects of medications in human populations.
Investigational New Drug
When there is data to show that a new drug is sufficiently safe to be used in clinical trials, the pharmaceutical company submits an Investigational New Drug (IND) application to the FDA.
New Drug Application
Upon completion of Phase 1-3 clinical trials, the drug company will seek drug approval from the FDA by submitting a New Drug Application (NDA).
Phase 4
Postmarketing Surveillance
The process by which a drug’s safety is monitored to identify potential problems with the use of the drug after receiving FDA approval
Primary data vs secondary data
Primary Data: Collected prospectively for a specific purpose
Secondary Data: Collection of preexisting data for some other purpose
Association vs Causation
Association: If a statistically significant difference was found
Causation: Can generalize one more time and draw a conclusion about causation
Criteria for Determining Causation
Strength of association
Consistency
Specificity
Time sequence
Biological gradient
Coherence
Experimental evidence
Analog w/ the existing literature
Randomized control trial
- Gold standard – strongest type of primary study design to support evidence-based medicine in making firm causal conclusions.
- The goal of a RCT trial is to measure a primary outcome in a highly selected group of individuals
- Randomization: subjects given an equal chance of being assigned to receive one or more clinical interventions
- Blinding: single, double, open-label
Case report vs case series
Case Report: Clinical event experienced by single patients exposed to a drug
Case series: Similar to a case report, except that it describes multiple patients
Both:
Purely observational:
No control group
Do not offer sufficient evidence to make any causal determinations
However, are useful in further clarifying previously determined causal relationships
Ecologic Studies
Analyses of secular trends
- In some situations, group, or aggregate, level data may be available rather than individual patient level
- Gather information in the aggregate (individuals not identified).
Used to analyze:
• Trends in an exposure (drug)
• Trends in a disease
• Test whether trends coincide
Limitations:
• Confounding bias – lack of data on individuals
• Conclusions for the aggregate level data are made on individual patients.
Cross- sectional study
“Prevalence study” – assess the exposure and outcome at one specific point in time in a sample population of interest to identify:
- prevalence of the outcome in the exposed group and the unexposed group
- potential relationships between exposures and outcomes
Key Characteristics:
• Outcome and exposure of interest are determined simultaneously
• Typically involves only one point in time but can be conducted over multiple time points/cross-sections.
• Cannot provide estimates of incidence but are well suited to provide estimates of the prevalence of a condition or exposure.
Case- Control Study
Case-control studies compare cases with a disease to controls without the disease:
- sample with disease of interest (cases)
- sample without disease of interest (control)
Both samples used to determine the exposure status of each individual.
The relative proportions of those exposed within the cases compared with those in the controls giving rise to the OR (odds of exposure in cases vs. odds of exposure in controls).
Key Characteristics:
• Useful when the outcome being examined is relatively rare
• Useful when one wants to study multiple possible causes of a single disease, as one can use the same cases and controls to examine any number of exposures as potential risk factors.
Cohort Study
Identify subsets of a defined population and follow them over time to determine development of disease in exposed vs. nonexposed.
Alternatively, a retrospective cohort study involves observing the past to identify a point in time where subjects were outcome-free and following through to the present or into the future to determine whether an outcome occurs.
Key Characteristics:
• May be desirable when the intentional exposure of a subject to some drug or intervention, as in an experimental manner, is either impossible or unethical. • General purpose is to estimate the risk or rate of some outcome among a cohort of individuals.
Advantages and Disadvantages of Study Designs
