Pharmacology Case Reports

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?

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