Classes 16-19 Flashcards
(25 cards)
List study designs from lowest to highest strength of evidence
I - In vitro/test tube Am - Animal Research Chris - Case Reports Christopher - Case Series Every other - Ecological Chris - Cross-Sectional Christopher - Case-Control Can - Cohort Immediately - Interventional Suck - Systematic Reviews My dick - Meta-Analyses
Interventional Study designs in order of increasing strength of evidence
Pre-clinical Phase 1 Phase 2 Phase 3 Phase 4
(T/F) All interventional study designs are analytical studies
True
Observational Study designs in order of increasing strength of evidence
Cases (Reports/Series) Ecological Cross-Sectional Case-Control Cohort
(T/F) All observational study designs are analytical studies
False. Only Cross-Sectional, Case-Control, and Cohort studies are analytical studies.
Pre-clinical studies
Bench/animal research
Prior to human investigation
Phase 1
- Small n (20-80)
- short duration
- First time in humans to assess safety/toxicity
- Also can be used secondarily to assess dosage and pharmacokinetics
Phase 2
- Larger n (100-300)
- Short-medium duration
- Expand on safety assessment
- Begin to assess efficacy
- Narrower inclusion criteria (Commonly utilize patients with condition of interest)
Phase 3
- Large n (1000-3000)
- Longer duration (months to a few years)
- Primary purpose to assess efficacy
- Secondary purpose safety
Phase 4
- Post marketing
- Primary purpose to assess long term effects (risk & benefits) in diseased patients
- Large n - expand use population
Advantages of Interventional trials
- Proves causation
- Only design used by FDA for approval process
Disadvantages of Interventional trials
- Cost
- Complexity/Time
- Ethical considerations (Risk vs Benefit)
- Generalizability from restricted inclusion criteria
Explanatory Interventional study
- NOT like clinical treatments
- Strict rules - can’t change treatment on patient to patient basis
Pragmatic interventional study
- Studies that are more applicable to clinical environment
- Usually no placebo - compare two or more real drugs
- Allow co-morbidities
- Allow patient to patient based clinical decisions
Limitations of pragmatic interventional study
Lose researchers control over intervention
Simple Interventional study
- Single randomization
- Commonly used to test single hypothesis
Factorial Interventional study
- Divides subjects into 2 or more groups then divides those into 2 or more subgroups
- Used to test multiple hypotheses simultaneously
Pros of factorial
- Improves efficiency of answering clinical questions
Cons
- Increases sample size
- Increases complexity
- Increases risk of drop outs
- May restrict generalizability of results
Parallel Interventional study
- Groups simultaneously and exclusively managed
- No switching of intervention groups after initial randomization
Cross over Interventional study
Groups serve as own control by crossing over from one interventional to another during study
Disadvantages of cross over
- Only suitable for long term studies
- Duration longer
- Carry over effects (fixed by wash-out)
- Treatment by period interaction (treatment different effects in different time periods)
Run-in/Lead-in phase
Subjects blindly given placebo to wash-out effects of anything prior to study
Wash-out
Subjects blindly given placebo to wash out effects of previous intervention before starting new intervention
