Clinical Trials and Observational Studies Quiz

5 Questions

Clinical trials assign interventions, while observational studies do not.

To decrease bias and ensure objectivity in the study.

It reduces confounding by randomizing within strata based on prognostic factors.

When therapy is believed to be superior or when randomization is impossible due to rarity of disease.

It is considered a gold standard for true clinical benefit and is easily measured.

Study Notes

Primary difference: Clinical trials involve intentional intervention or treatment, whereas observational studies observe participants without intervention.

Purpose: To reduce bias by concealing the allocation of participants to treatment or control groups from participants, investigators, or both.
Blinding helps ensure objective outcomes, reduces expectation bias, and promotes accurate results.

Function: To distribute participants evenly across different strata (subgroups) based on prognostic factors to minimize confounding variables.
Stratification ensures balance between groups, enhancing the trial's validity and accuracy.

Typically used when:
- A comparative group is not feasible or ethical.
- The intervention is novel, and a control group is not applicable.
- The primary endpoint is a binary response (e.g., response/non-response).

Significance as a primary endpoint: Represents the time point at which 50% of participants have experienced an event (e.g., death, disease progression).
Median survival time provides a more informative and meaningful outcome measure than overall survival rates.

5 Questions