Lecture 1

Question 1

Prospective definition

Answer 1

following a group of patients over time to determine the outcome of an exposure

Question 2

Retrospective definition

Answer 2

looks backwards in time and examines exposures in relation to an outcome that has already been established at the start of the study

Question 3

PICO of clinical trials

Answer 3

patients, intervention, control, outcomes

Question 4

data safety monitoring boards

Answer 4

independent scientists who monitor safety and scientific integrity of clinical trial. Can recommend to stop a clinical trial if harm is suspected, intervention is not likely to likely to serve purpose, or there is enough evidence of therpeutic benefit

Question 5

Observational study

Answer 5

investigator passively obseves as nature takes its course, can be prospective or retrospective

Question 6

prospective study

Answer 6

study design follows subject going forward in time. Researchers group subjects based on exposure and followimpact of exposure over time (exposure can be a risk or protective factor)

Question 7

retrospective study

Answer 7

investigators study subjects and occurances that have already happened, the exposure and outcome have occured and we are looking at past data, records, and self reports.

Question 8

three types of observational study

Answer 8

cross-sectional, cohort, case-control

Question 9

cross-sectional study

Answer 9

exposure and outcome are obtained simultaneously.
-relationship between exposure and outcome prevalence in a defined population without regard to changes over time
-provides snapshot of outcome and associated risks at specific time

Question 10

case-control study

Answer 10

outcome is determined before exposure is measured
-multiple exposures in relation to an outcome, subjects are sorted as cases or control, and their exposure histories are compared
-retrospective

Question 11

cohort study

Answer 11

examine multiple health effects of an exposure, subjects defined according to exposure level and followed over time for outcome occurance
-exposure determined before the outcome is measured
-usually prospective

Question 12

advantages and disadvantages of cross-sectional

Answer 12

-Adv: less time consuming, inexpesnive, quick picture of exposure or outcome
-dis: difficult to determine temporal relationship between exposure and outcome

Question 13

advantages and disadvantages of case control study

Answer 13

adv: inexpensive, less time consuming, evaluate effects of multiple exposures
Dis: subject to recall bias, difficult to establish chronology of exposure and outcome

Question 14

advantages and disadvantages of cohort study

Answer 14

adv: evaluate mutliple effects of single exposure, direcly measure incidence, clear chronological relationship between exposure and outcomes
dis: expensive, time consuming

Question 15

intervention definition

Answer 15

process or action variable that is the focus of a clinical study (drug, device, vaccine, surgery, survey, interview, etc)

Question 16

Active controlled

Answer 16

experimental drug compared to already liscensed drug

Question 17

placebo controlled

Answer 17

experimental drug compared to substance with no active ingredient but looks the same

Question 18

add on

Answer 18

all subjects receive existing treatment but some are given the experimental drug while other ar given placebo or nothing in addition