Prevention, Ethics and Biostatistics

Question 1

What are the USPSTF recommendations for cholesterol screening in patients WITHOUT CAD risk factors?

Answer 1

• Men begin at 35
• women at 45yo
• screen Q5years

Question 2

USPSTF recommendations for screening mammograms?

Answer 2

• women >50yo

- q2 years

Question 3

Legal obligation to conform to a reasonable standard of care?

Answer 3

Duty of care

Question 4

Failure to conform to the standard of care?

Answer 4

Breach of duty

Question 5

The breach of duty is determined to be the cause of injury/harm?

Answer 5

Causation

Question 6

what are the 2 ways that the standard if care can be established in a malpractice case?

Answer 6

• expert testimony

- Res ipsa loquitur (“it speaks for itself”)

Question 7

Supervisors are responsible for the actions of their subordinates?

Answer 7

Vicarious liability

Question 8

Incidence

Answer 8

new cases/total # of people at risk

Question 9

Prevalence

Answer 9

of people with disease/total population

Question 10

Sensitivity

Answer 10

A/(A+C)

Question 11

Specificity

Answer 11

D/(D+B)

Question 12

PPV

Answer 12

A/(A+B)

true positives that tested positive

Question 13

NPV

Answer 13

D/(C+D)

How many true negatives our of all of the negative tested

Question 14

Do high-prevalence diseases have a high PPV or a high NPV?

Answer 14

High PPV

Question 15

Relative Risk

Answer 15

RR= (A/(A+B))/(C/(C+D))

• RR>1 –> exposure increases risk of disease
• RR

Question 16

What study is used to develop relative risk?

Answer 16

Cohort study

Question 17

Odds Ratio

Answer 17

(AxD)/(CxB)

used to estimate RR in low0-prevalence

Question 18

What study is used to develop odds ratio?

Answer 18

Case-control

Question 19

Attributable Risk

Answer 19

(A/(A+B)) - (C/(C+D))

Question 20

Absolute Risk Reduction

Answer 20

ARR= (C/(C+D)) -(A/(A+B))

Question 21

Number needed to treat

Answer 21

1/ARR

Question 22

What is a statistically significant p-value?

Question 23

What does a lower p-value indicate?

Answer 23

the more statistically significant the finding it (the less likely it was just due to chance)

Question 24

Confidence interval

Answer 24

CI=mean +/- (Zx SEM)

• For 90%, Z=1.645
• for 95%, Z=1.96
• for 99% CI, Z=2.58

Question 25

If the CI for an odds ratio or relative risk crosses one, what does this indicate?

Answer 25

No association between risk and disease

Question 26

If the CI for a study between 2 treatment groups crosses 0, what does this indicate?

Answer 26

No actual difference between the 2 treatments

Question 27

what percentage of the study population falls within 1 SD of the mean? 2 SD? 3 SD?

Answer 27

1=68%
2=95%
3=99.7%

Question 28

What can you identify in case-control studies? What can you calculate?

Answer 28

• potential risk factors (these are ALWAYS retrospective)

- Odds ratio

Question 29

What is a cohort study? What can you calculate?

Answer 29

• Follow a cohort that is exposed to a given risk factor to see how many develop a disease (prospective)
• Relative risk

Question 30

Type of bias? When studying the effects that infection control education has on physicians, both the experimental and the control groups improve their hand hygiene

Answer 30

Hawthorne effect (chase behavior when you know you’re being observed)

Question 31

Bias? Sending out a survey to people diagnosed with a fatal illness 5 years after a diagnosis will preferentially sample those will low-grade disease or fewer comorbidities

Answer 31

Late look bias

Question 32

Bias? Sicker patents are preferentially encouraged to enroll in a study

Answer 32

Selection bias