L8- Clinical Epidemiology, Observational / Experimental Studies

Question 1

define case series

Answer 1

a group of similar people/patients, usually in a small quantity, that undergo the same tests/treatments/prognosis for a similar condition

Question 2

randomized controlled trials can also be called…..

Answer 2

• clinical trials

- longitudinal prospective study

Question 3

describe cross-over study

Answer 3

similar to randomized controlled trials except after initial treatment, therapeutic and placebo groups switch after some period of time

Question 4

describe cross-sectional surveys

Answer 4

surveys a population and determines the relationship between a risk factor and a disease

Question 5

describe ecological studies

Answer 5

a cross-sectional study that relate the frequency of some characteristic to some outcome of interest, comparing geographic areas to other geographic areas, not comparing individuals

Question 6

experimental studies are also known as….

Answer 6

interventional studies

Question 7

define the principle of equipoise

Answer 7

is the trial ethical in that the researcher is uncertain of relative effectiveness of treatments tested

-no patient is knowingly disadvantaged by being randomized

Question 8

list the 3 types of experimental designs (clinical setting)

Answer 8

• non-experimental: no control group, everyone is being tested
• quasi-experimental: control group and test group without randomization
• experimental / RCT: randomized control and test group

Question 9

RCT can also be called….

Answer 9

parallel trial (opposite of cross-over trial)

Question 10

list the 4 phases of a clinical trial

Answer 10

1) enrollment
2) allocation- split into groups
3) follow-up
4) analysis

Question 11

define drug efficacy

Answer 11

does the drug work under ideal experimental circumstances

Question 12

define drug effectiveness

Answer 12

does drug work in real-world or normal circumstances`

Question 13

efficacy is related to (1)

effectiveness is related to (2)

Answer 13

1- internal validity

2- external validity / generalizability

Question 14

Intention-to-treat vs Explanatory

Answer 14

Intention to Treat- analyze all subjects, whether they complete the trial or not

Explanatory- analyze only those subjects that completed the trial correctly

Question 15

define equivalence, superiority, and non-inferiority trials when comparing established drug A and new drug B

Answer 15

Equivalence- drugs are equal, none are better than the other

Superiority- drug A is superior

Non-inferiority- drug B is not inferior

Question 16

Hawthorne effect

Answer 16

patients are more compliant and have improved health behaviors when under observation

Question 17

describe statistical significance

Answer 17

α = 0.05%

if p value < α => statistically significant

Question 18

describe clinical significance

Answer 18

does the drug actually help the patient - via symptoms, lab values, radiologically, etc

Question 19

if a trial is clinically significant but not statistically significant what does it indicate

Answer 19

potential trend, although it could be due to chance

Question 20

if a trial is statistically significant but not clinically significant what does it indicate

Answer 20

large sample size - good info on ‘best’ clinical efficacy

Question 21

what is the impact of Power on a sample size (include ideal value)

Answer 21

Power = 1 - β, [β is number of false negatives]

higher the power, the bigger the sample size (80% is ideal)