Behavioral Science Flashcards
Clinical trial phases
o Phase 1: “Is it safe?” Small number of healthy volunteers are given the drug
o Phase 2: “Does it work?” Small number of patients with the disease use the drug
o Phase 3: “Is it as good or better?” Large number of patients with the disease are randomly assigned to either the treatment under investigation or the best available treatment (or placebo)
o Phase 4: “Can it stay” Postmarketing surveillance of patients after treatment is approved – detects long term or rare effects
Sensitivity
proportion of all people with disease who test positive (When the test is negative, it rules out disease)
Specificity
proportion of all people without disease who test positive (When the test is positive, it rules in disease)
Positive predictive value
How is this affected by prevalence of disease?
the probability that a person with a positive test actually has the disease
Increased prevalence of disease = higher PPV
Negative predictive value
How is this affected by prevalence of disease?
the probability that a person with a negative test actually doesn’t have the disease
Increased prevalence of disease = lower NPV
Case-control study
What is commonly used to evaluate this?
compares a group of people with a disease to a people without a disease and looks for prior risk factor/exposure
Ex. Patients with COPD had higher odds of a history of smoking than those without COPD
Odds ratio
Cohort study
What is commonly used to evaluate this?
compares a group with a known exposure/risk factor to a group without the exposure/risk factor and looks to see if they develop disease
Ex. Smokers had a higher risk of developing COPD than nonsmokers
Relative risk
Attributable risk
the difference in risk between exposed and unexposed groups, or the proportion of disease occurrences that are attributable to the exposure
o AR = (a/a+b) – (c/c+d)
Absolute risk reduction
the difference in risk attributable to the intervention as compared to a control
o ARR = (c/c+d) – (a/a+b)
Number needed to treat (NNT)
number of patients who need to be treated for one patient to benefit
o NNT = 1/ARR
Number needed to harm (NNH)
number of patients who need to be exposed to a risk factor for one patient to be harmed
o NNH = 1/AR
Standard deviations
1) 68%
2) 95%
3) 99%
Positive skew
Mean>median>mode
Negative skew
mode>median>mean
Top three causes of cancer deaths for men and women
o Men: Lung, prostate, colorectal
o Women: Lung, breast, colorectal
