Interpreting and Applying Study Results 1

Question 1

Internal Validity

Answer 1

Are the study findings true?
Timing: cause precedes effect
Relationship: cause and effect are related
Plausibility: mechanisms; non-spurious relationship

Question 2

External validity

Answer 2

Are study finding generalizable to populations other than the study sample?
People: evaluate inclusion/exclusion criteria
Situation: evaluate study setting

Question 3

Threats to internal validity

Answer 3

Confounding
Systematic error/bias
History
Minim: Randomization, blinding, controls, Intent to treat (ITT) vs Per protocol (PP) analysis

Question 4

Intent to Treat ITT

Answer 4

Estimate treatment effect as assigned
All randomized pts must be included
Mandated by the FDA for industry clinical trials

Question 5

Per Protocol PP

Answer 5

Estimate treatment effect as received
Only pts who complete the study are included
Secondary

Question 6

ITT or PP in Superiority Studies

Answer 6

ITT

Question 7

ITT or PP in Non-inferiority studies

Answer 7

ITT + PP

Question 8

Threats to External validity

Answer 8

Placebo effect, Hawthorne effect, Pygmalion effect

Differences between study pop vs real life or study environment vs real life

Question 9

Evidence Based Medicine

Answer 9

Clinical decisions based on objective scientific evidence

Requires clinician to critically evaluate the available body scientific evidence

Question 10

ISEA

Answer 10

Pharmacotherapy Decisions
I: Identify the information you need and formulate question (PICO)
S: Perform literature search for scientific evidence
E: Critically evaluate
A: Interpret and apply to your pt situation

Question 11

PICO

Answer 11

Patient
Intervention
Comparison
Outcome

Question 12

Points to consider

Answer 12

Need
Efficacy
Safety
Misuse
Cost/cost-savings