BIOL 437 Week Nine p.2 (Experimental Studies) Flashcards
inclusion criteria
-broad vs. specific
>related to extent of generalization
exclusion criteria
- that will help control error
- those with difficulty in complying (ex. alcoholics)
sample size calculations
- used to ensure number of participants is adequate to test the specific hypothesis
- formulation of null and 1 or 2 -tailed research hypothesis
- desired level of statistical significance
- use table or formula
characterize the cohort
- identify info
- demographics
- variables that may be associated with outcome
- clincial factors
- typically the first table in a final report
measure variables
- that may be associated with the outcome
- change during the study
- to assure disease is or is not present at baseline
- measures various predictors of outcomes
- be parsimonious
choosing comparision group
- not contaminated by treatment
- ideally ‘blind’
- status quo vs. new treatment
assuring compliance
- call day beofre clinical visit
- providing reimbursement
- adhering to intervention protocol
- measuring compliance
adhering to intervention protocol
- should be well-tolerated (ex. minimal side effects)
- taking once a day vs. complex schedule
selecting patient populaiton compromise between
- The population most efficeint for answering the clinical question
- The population best for generalizing the study findings
selecting endpoint
-often complicated
-surrogate endpoint
>don’t do death
>useful in randomized controlled trials when the outcome of interest is rare
phase 1 trial
- unblinded, uncontrolled study with less than 30 patients
- to determine the safety of a test in humans
- patients often have advanced disease and have tried other options
- often undergo intense monitoring
phase ll trial
-relatively small (up to 50) randomized, blinded trials
-test:
>tolerability
>safe dosage
>side effects
>how the body copes with the drug
-what disease it can fight against
phase III trial
- much larger (maybe 1000s)
- involve random assigment
- used to evaluate efficacy of new treatment
- different dosages often part of evaluation
phase IV trial
- large study conducted after the therapy has been approved by health canada
- asseses rate of serious side effects and explore further uses
types of randomized controlled trail
- Run-in design
- Factorial design
- Randomization of matched pairs
- Group randomization
run-in design
- all subjects in cohort placed on placebo
- then those who remain in study are randomly assigned to either treatment or placebo
- limitation: subjects who remain may not reflect the population of interest
- can be useful to minimize bias due to loss to follow-up
factorial design
- 2 or more series of treatments are tried in all combinations
- can evaluate efficacy of 2 interventions in a single cohort
- subjects assigned 1 of 4 groups randomly
randomization of matched pairs
-comparison group similar in regards to confounding
-more accurate estimates than unmatched
-matched according to confounding
>1 assigned to study
>1 to control
groups may involve
- practices
- schools
- hospitals
- communities
individuals within a cluster
-likely to be more similar to each other compared to those in other clusters
ethical principles
- lead to greater likelihood of benefits
- protect subjects from harm
- ensure people’s time is not wasted
- desire to participate is not frustrated
Tuskegee syphillis study
- Black americans
- told being treated but weren’
- no informed consent
- diagnostic lumbar punctures (spinal taps)
- contagious nature never told to families
- found that 20% descrease in life expectancy
