B5-021 EBM C. difficile

Question 1

causative agent of antibiotic associated colitis

Answer 1

C. difficile

Question 2

most common microbial cause of HAIs in US hospitals

Answer 2

C. difficile

Question 3

how does a C. difficle superinfection occur?

Answer 3

1. C. dif acquisition
2. Antibiotics knock out normal GI flora
3. C. diff superinfection and antibiotic associated colitis

Question 4

how many patients experience recurrence following C. diff infection?

Answer 4

1 in 5

Question 5

what was the null hypothesis in a non-inferiority trial?

Answer 5

is the new treatment inferior to the standard treatment

Question 6

what is the biggest limitation of a systematic review?

Answer 6

lack of clarity in the primary study question

Question 7

major differences in the outcome seen among the studies included in systematic reviews

Answer 7

heterogeneity

Question 8

• frequently used to estimate treatment effects
• can provide justification for formal RCT

Answer 8

observational cohort study

Question 9

what does heterogenity suggest in systematic reviews that include both RCTs and observational cohort studies?

Answer 9

confounding in observational studies

Question 10

what type of bias are we concerned about in a systematic review?

Answer 10

confounding

Question 11

PICO

Answer 11

Population
Intervention
Control
Outcome

Question 12

why do we randomize patients?

Answer 12

to ensure both groups are relatively equal at baseline

Question 13

NNT calculation

Answer 13

1/ARR

Question 14

study population is defined on the basis of outcome status with backwards directionality

Answer 14

case control study

Question 15

works well in situations where the outcome of interest is rare

Answer 15

case control study

Question 16

small study that aggregates information on a few studies and is typically used to describe a new or novel clinical presentation

Answer 16

case series study

Question 17

compares frequency of and exposure and outcome at a population level

Answer 17

ecologic study

Question 18

when the exposure of interest and outcome of interest are assessed at the same time, a […] design is employed

Answer 18

cross sectional

Question 19

conducted using one time survey

Answer 19

cross sectional study

Question 20

used to calculate prevalence of certain condition, exposure, or state

Answer 20

cross sectional study

Question 21

used to describe continous data

Answer 21

mean
median
mode

Question 22

best used to describe cumulative data across study populations

Answer 22

mean and standard deviation

Question 23

best used for categorical data

Answer 23

risk

Question 24

allows researchers to compare two treatments and evaluate if the treatment of interest is as good as the control

Answer 24

non inferiority trial

Question 25

bias of concern in cross sectional and case control designs

Answer 25

recall

Question 26

addresses possible problems in the makeup of the study population

Answer 26

selection bias

Question 27

• observer-expectancy effect
• researcher unconsciously influences study participants due to some unrecognized cognitive bias

Answer 27

pygmallion effect

Question 28

participants change behavior because they are being observed

Answer 28

Hawthorne effect

Question 29

length of time between detection of disease and the time when usual clinical presentation will occur is altered due to study

Answer 29

lead time bias

Question 30

why survival time is not used as an indicator of screening test effectiveness in RCT

Answer 30

lead time bias

Question 31

time is added preferentially to the screened group just because the disease was detected prior to typical clinical presentation

Answer 31

lead time bias