Evidence Based Medicine

Question 1

what is the best type of evidence?

Answer 1

systematic review

Question 2

what are the three main types of study design?

Answer 2

observational descriptive
observational analytical
experimental

Question 3

name two types of observational descriptive studies

Answer 3

case reports

case series

Question 4

name three types of observational analytical studies

Answer 4

cross sectional study
case control study
cohort study

Question 5

name a type of experimental study

Answer 5

randomised control trials

Question 6

what two things are looked at when selecting patients for RCTs?

Answer 6

inclusion criteria

exclusion criteria

Question 7

state some examples of inclusion criteria for RCTs

Answer 7

likely to benefit from the treatment

unlikely to be harmed

Question 8

name some examples of exclusion criteria for RCTs

Answer 8

clear preference for the intervention or control by the patient or the doctor

patient unlikely to adhere to the treatment or follow up

Question 9

what is the aim of patient selection in RCTs?

Answer 9

have a well defined group with an increased likelihood of detecting an effect

Question 10

what is the rule of thumb when it comes to losing patients in RCTs?

Answer 10

fewer than 20% lost with similar losses for the intervention and the control

Question 11

what is confounding?

Answer 11

when the association between an exposure and an outcome is actually the result of another variable

Question 12

what is absolute risk (AR)?

Answer 12

the number of events in treated or control groups, divided by the number of people in that group

Question 13

what is the ARC?

Answer 13

the AR of events in the control group

Question 14

what is the ART?

Answer 14

the AR of events in the treatment group

Question 15

how do you calculate the absolute risk reduction (ARR)?

Answer 15

ARC - ART

Question 16

how do you calculate the relative risk (RR)?

Answer 16

ART/ARC

Question 17

how do you calculate the relative risk reduction (RRR)?

Answer 17

(ARC-ART)/ARC

Question 18

how do you calculate the number needed to treat (NNT)?

Answer 18

1/ARR

Question 19

what are some qualitative research methods?

Answer 19

ask people

observe people

Question 20

what is triangulation>

Answer 20

when the area under investigation is looked at from different perspectives, with two or more research methods

Question 21

what is the role of triangulation?

Answer 21

ensure understanding is as complete as possible

confirm interpretations

Question 22

what is sensitivity?

Answer 22

how well a test detects having the disease

Question 23

how do you calculate sensitivity?

Answer 23

number of true positives/number of people with the disease x100

Question 24

describe what a highly sensitive test will do

Answer 24

pick up most of the disease whilst having very few false negatives

Question 25

what is specificity?

Answer 25

how well a test picks up not having the disease

Question 26

how do you calculate specificity?

Answer 26

number of true negatives/number of people without the disease x100

Question 27

describe what a highly specific test will do

Answer 27

correctly detects no disease with very few false positives

Question 28

what is the positive predictive value?

Answer 28

how reliable a test result is when it shows disease is present

Question 29

how do you calculate positive predictive value?

Answer 29

true positives/all positives x 100

Question 30

what is the negative predictive value?

Answer 30

how reliable a test is when it shows that disease is not present

Question 31

how do you calculate negative predictive value?

Answer 31

true negatives/all negatives x100

Question 32

what can affect the predictive values?

Answer 32

prevalence of disease

Question 33

what is opportunity cost?

Answer 33

a benefit that a person could have received but gave up to take another course of action

Question 34

name three types of economic evaluation

Answer 34

cost effective analysis cost utility analysis cost benefit analysis

Question 35

what is the best study design to determine the prevalence of a disease?

Answer 35

cross sectional study

Question 36

in a randomised control trial, what is reduced by randomisation?

Answer 36

selection bias

Question 37

what study type is being described: a study that looks at all children born at a hospital in one year, measuring their height at intervals up to four years of age?

Answer 37

cohort study

Question 38

what does external validity mean?

Answer 38

the extent to which one can appropriately apply results from a study to other populations

Question 39

what is the best study design to research the aetiology of a disease?

Answer 39

cohort study

Question 40

what does statistical significance mean?

Answer 40

the results of a study are unlikely to have arisen by chance alone

Question 41

what measure seeks to measure the benefits to individuals following a medical intervention?

Answer 41

QALYs

Question 42

what is saturation?

Answer 42

when there is no longer any need to sample more people to reach new conclusions or to back up/challenge existing conclusions