Clin. Epi. Study Designs - Experimental

Question 1

describe randomized controlled trials

Answer 1

Question 2

describe the advantages vs disadvantages of randomized controlled clinical trials

Answer 2

Question 3

describe the principle of equipoise

Answer 3

• genuine uncertainty as to whether the outcomes of the research will be beneficial
• if the answer to the research question is known, the research is not “in equipoise”
• subjects may participate in a randomized controlled research study only when uncertainty surrounds which arm they should be in

Question 4

describe examples of randomization

Answer 4

Question 5

describe the levels of blinding

Answer 5

Question 6

describe efficacy

Answer 6

• efficacy of an agent being tested, such as vaccine, can be expressed in terms of the rates of developing disease in the vaccine and placebo groups

Question 7

describe phase I trials

Answer 7

• these trials are clinical pharmacologic studies–small studies of 20 to 80 patients that look at safety issues with the new drug or other treatment
  
  • toxic and pharacologic effects are examined, including safety, safe ranges of human dosage, and the side effects observed with the new treatment
• if the drug passes these studies, it then undergoes phase II studies

Question 8

describe phase II trials

Answer 8

• phase II studies consist of clinical investigations of 100 to 300 patients in order to evaluate the efficacy of the new drug or treatment and to further assess its relative safety

Question 9

describe phase III trials

Answer 9

• these studies are large-scale randomized controlled trials for effectiveness and relative safety
• these studies often include 1000 to 3000 or more participants

Question 10

describe phase IV studies

Answer 10

• phase IV studies, which are also called post-marketing surveillance, are important for monitoring new agents as they come into general use by the public

Question 11

summarize the 4 phases of drug trials

Answer 11

Question 12

describe internal vs external validity

Answer 12

• internal validity
  
  • the study was done properly and the findings of the study are therefore valid in the study population
• external validity
  
  • findings of the study are generalizable from the study population to the defined population and presumably, to the total population

Question 13

describe comparative effectiveness research

Answer 13

• some randomized trials are designed to compare a new therapy to a placebo
• other randomized trials focus on comparing a new treatment with an older accepted treatment in order to determine whether the new treatment is superior to th established treatment

Question 14

describe equivalence studies

Answer 14

• as newer and cheaper medications are developed, studies are often conducted to determine whether the new, cheaper alternatives are as effective as the most expensive interventions whose effectiveness has already been documented
• determines if the cheaper interventions are as effective as the more expensive treatments
• the term non-inferiority studies has also been used

Question 15

describe superiority studies

Answer 15

• superiority studies are studies in which newly developed agents are evaluated to determine whether they are more effective (superior) than currently available interventions

Question 16

describe the 2 approaches of analyzing results

Answer 16

• intention to treat
  
  • analyze according to group initially assigned by randomization regardless of whether they received treatment
• explanatory
  
  • analyze according to treatment actually received, regardless of randomization