Usmle Step 1-Public Health Sciences

Front 1

Clinical trial phases ?

Back 1

Phase 1: is it safe ? on healthy volunteers

Phase 2: Does it work? on patients with disease

Phase 3: Is it better than others

Phase 4: Can it stay at market? long-term side effects

Front 2

Case-control study compares ? and looks for ?

Back 2

Compares a group of people with disease to agroup without disease.

Looks to see if odds of prior exposure or risk factor differs by disease state.

Patients with COPD had higher odds of a history of smoking than those without COPD.

Front 3

what is Sensitivity?

Back 3

Proportion of all people with disease who testpositive

Front 4

what the odds ratio ?

Back 4

odds of an event (disease) occurring giving a certain exposure to odds of occurring in the absence of the exposure

OR=(a/b)/(c/d)

Front 5

what is relative risk ?

Back 5

risk of developing disease in exposed to unexposed group. (eg, if21% of smokers develop lung cancer vs 1% ofnonsmokers, RR = 21/1 = 21).

For rare diseases(low prevalence), OR approximates RR.

RR = a/(a + b)/c/(c + d)

RR = 1 no association between exposure anddisease.

RR > 1 exposure associated with diseaseoccurrence.

RR < 1 exposure associated with diseaseoccurrence.

Front 6

what is Attributable risk?

Back 6

The difference in risk between exposed and unexposed groups, or the proportion of disease occurrences that are attributable to the exposure (eg, if risk of lung cancer insmokers is 21% and risk in nonsmokers is 1%,then 20% of the lung cancer risk in smokers is attributable to smoking).

AR= a/a+b- c/c+d

Front 7

what is Absolute risk reduction?

Back 7

The difference in risk (not the proportion)attributable to the intervention as comparedto a control (eg, if 8% of people who receivea placebo vaccine develop the u vs 2%of people who receive a flu vaccine, thenARR = 8% − 2% = 6% = .06).

ARR= c/c+d-a/a+b

Front 8

what is Number needed to treat?

Back 8

Number of patients who need to be treated for1 patient to benefit. Lower number = better treatment.

NNT = 1/ARR

Front 9

what is Precision ?

Back 9

reliability of a test. the absence of random variation in a test.

Front 10

what is accuracy ?

Back 10

how close to the bulls eye. The absence of systemic error in a test

Front 11

what is crude mortality rate ?

Back 11

deaths/population

Front 12

what is cause-specific mortality rate ?

Back 12

death from a cause/population

Front 13

what is case-fatality rate ?

Back 13

death from cause/number of persons with disease

Front 14

what is proportionate mortality rate ?

Back 14

deaths from cause/all deaths

Front 15

what is Type I error (α)?

Back 15

Stating that there is an effect or difference when none exists (null hypothesis incorrectly rejected in favor of alternative hypothesis). False positive

telling a man you are pregnant !

Front 16

what is Type II error (β)?

Back 16

Stating that there is not an effect or differencewhen one exists (null hypothesis is not rejectedwhen it is in fact false). False negative

Telling a pregnant lady you are not pregnant.

saying smoking not a risk factor for lung cancer.

Front 17

t-test is used for ?

Back 17

to check the difference between means of two groups

Front 18

Chi-square (χ2) is used for ?

Back 18

Checks differences between 2 or morepercentages or proportions of categoricaloutcomes (not mean values).

Front 19

ANOVA is used for ?

Back 19

Checks differences between means of 3 or more groups.

3 words: ANalysis Of VAriance. 3 groups

Front 20

What is gender identity ?

Back 20

sense of maleness or femaleness

Front 21

what is gender role ?

Back 21

behavior based on gender identity

Front 22

what is sexual identity ?

Back 22

based on secondary sexual characteristics

Front 23

what is sexual orientation ?

Back 23

Love object preference

Front 24

what is primary prevention ?

Back 24

prevention of disease before it occurs. e.g., vaccination

Front 25

secondary prevention ?

Back 25

screen early for asymptotic disease e.g, pap smear. early detection of disease not necessarily preventing the disease from happening.

Front 26

what is tertiary prevention ?

Back 26

treatment to reduce complications. e.g., chemotherapy

Front 27

what is quaternary prevention ?

Back 27

identifying patient at risk of unnecessary treatment, protecting from harm of the new intervention e.g., electronic sharing of patient records to avoid duplicating recent lab studies.

Front 28

what is Health Maintenance Organization ?

Back 28

Patients are restricted (except in emergencies) to a limited panel of providers who are in thenetwork

Front 29

what is Point of Service medical insurance ?

Back 29

Patients are allowed to see providers outside of the network, but have higher out-of-pocket costs,including higher copays and deductibles, for out-of-network services. Requires referral from primary care provider to see a specialist.

Front 30

what is Preferred Provider Organization?

Back 30

Patients are allowed to see physicians who are within or outside of the network. All services havehigher copays and deductibles. Does not require referral.

Front 31

what is Exclusive Provider Organization?

Back 31

Patients are limited (except in emergencies) to a network of doctors, specialists, and hospitals Does not require referral

Front 32

what is selection bias ?

Back 32

non randomization sampling or treatment of allocation of subjects.

Front 33

some ways investigator can lower bias in study design ?

Back 33

Randomization

Double blind

Using a control group

Front 34

what equation for standard error of the mean ?

Back 34

SEM=standard deviation/square root of sample size

Front 35

what the equation for confidence interval ?

Back 35

CI= mean± Z score(Standard error of the mean )

Front 36

What is current recommendation of giving a meningococcal vaccine?

Back 36

All children age 11-12 y

Booster at 16

Can be given to children as young as 2 years if high risk

Front 37

What is current recommendation of giving a meningococcal vaccine?

Back 37

All children age 11-12 y

Booster at 16

Can be given to children as young as 2 years if high risk

Front 38

Which adult patient populations should receive pneumococcal polysaccharide PPSV23 vaccine?

Back 38

All ptns above age 65

Ptns younger than 65 if high risk like asthma, COPD, smoker, resident of long term care facilities, cardiovascular disease, diabetics, liver disease, aspleenia, CSF leaks

Front 39

What is current recommendation of giving a meningococcal vaccine?

Back 39

All children age 11-12 y

Booster at 16

Can be given to children as young as 2 years if high risk

Front 40

Which adult patient populations should receive pneumococcal polysaccharide PPSV23 vaccine?

Back 40

All ptns above age 65

Ptns younger than 65 if high risk like asthma, COPD, smoker, resident of long term care facilities, cardiovascular disease, diabetics, liver disease, aspleenia, CSF leaks

Front 41

What diarrheal disease is reportable disease?

Back 41

Salmonella

Shigella

Front 42

What is premium pay?

Back 42

Monthly payments by patient

Front 43

What is premium pay?

Back 43

Monthly payments by patient

Front 44

What is co-pay ?

Back 44

Amount patients pays at service regardless of premium. E.g, when they visit ER,

Front 45

What is premium pay?

Back 45

Monthly payments by patient

Front 46

What is co-pay ?

Back 46

Amount patients pays at service regardless of premium. E.g, when they visit ER,

Front 47

What is Deductible ?

Back 47

Amount patient must out of pocket before the health insurance begins to pay. E.g, if you have a high premium plan you need to pay less deductible.

Front 48

What is premium pay?

Back 48

Monthly payments by patient

Front 49

What is co-pay ?

Back 49

Amount patients pays at service regardless of premium. E.g, when they visit ER,

Front 50

What is Deductible ?

Back 50

Amount patient must out of pocket before the health insurance begins to pay. E.g, if you have a high premium plan you need to pay less deductible.

Front 51

What is DMAIC ?

Back 51

1. Define the problem

2. Measure, establish an objective baseline

3. Analyze, identify the cause

4. Improve by intervention

5. Control to maintain the improvement