24. Experimental (interventional) epidemiological studies

From greek.doctor
  • Clinical trials vs field trials
    • Clinical trials
      • Are performed on patients
      • Involve treatments
      • Determine secondary and tertiary preventative measures
    • Field trials
      • Are performed on healthy people
      • Involve prophylactic measures
      • Determine primary preventative measures
  • Randomized control trials (RCT)
    • Gold standard of clinical trials
    • Steps
      • People from a sample population are randomly allocated into an intervention group and a control group
      • The intervention group is given the drug/therapy/etc.
      • The control group is given a placebo/the current gold standard in therapy/nothing
      • After a period of time the incidence of a specific disease between the two groups is compared
    • Blinding
      • No blinding – the researchers and the study participants know which group they belong to
      • Single-blinded – only the researchers know which group the study participants belong to
      • Double-blinded – neither the researchers nor the study participants know who is in the control and who is in the interventional group
    • Examples
      • 2 studies tried giving beta-carotene to smokers to see if cancer risk reduced – but the cancer risk actually increased
  • Crossover trial
    • Similar to RCT, but the people in the control and intervention group switch during the trial period
    • This allows the patients to serve as their own controls