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Epidemiology, Biostatistics, Ethics - COMLEX/USMLE Step 3

Terms in this set (70)

Define primary prevention of disease, and list some examples.
Prevent onset of disease

(ex. vaccinations, diet/exercise)
Define secondary prevention of disease, and list some examples.
Prevent progression of disease

(ex. screening tests, HTN meds)
Define tertiary prevention of disease, and list some examples.
Prevent complications of disease

(ex. surgery, rehabilitation)
Screening guidelines for Colon CA
Start at age 50 (or 10y before first degree relative got cancer, whichever sooner)

End at age 75

Screening measures:
- Colonoscopy q 10y
- Flex Sig q 5y + FOBT q 3y
- FOBT q 1y
Screening guidelines for Breast CA
If there is ⊕ FHx, start at ages 40-49. If none, start at age 50

Stop at age 74

Screening measures:
- Mammogram q 2y

(⊕ FHxx* = BRCA1/2 addition)
Screening guidelines for Cervical CA
Start at age 21 (regardless of sexual history)

Continue till 65

Screening measures:
- Pap smear q 3y
- (if >30 yo AND hx of normal Pap = Pap + HPV q 5y)
Screening guidelines for Lung CA
Reserved for those with ≥30 PY hx OR they quit < 15 y prior

Begin at 55

Continue to age 80 (or if quitter, stop when it > 15 y from quit date)

Screening measures:
- Low Dose CT q 1y
Screening guidelines for cholesterol
Males start at 35
Females start at 45
(both in 20s if high risk)

Screening measure:
- Fasting Lipid Panel q 5y
HTN screening guidelines
EVERYONE!

Check BP EVERY VISIT!
Osteoporosis screening guidelines
Females at age 65 (high risk at 60)

Screening measure:
- 1 time DEXA scan
AAA screening guidelines
Males at age 65-75 who have EVER smoked

Screening measure:
- 1 time Abd U/S
STD screening guidelines
Anyone who is sexually active

Perform rapid tests at least once, preferably q 1y
Hepatitis C screening guidelines
All Baby Boomers (1940s-1965)

Get a 1 time antibody screen
Depression screening guidelines
All Adults!

Use PHQ-9 based on clinical judgement
Alcohol abuse screening guidelines
All Adults!

Conduct an interview, use the CAGE questionnaire

(≥2 positive responses = ↑ likelihood of EtOH abuse)
For the Pneumococcal vaccination, you receive __-valent as a child
13-valent
For the Pneumococcal vaccination, you receive __-valent as an adult when you are ≥ __ y.o.
23-valent; ≥ 655* y.o.

(can give earlier, for high risk populations)
(True/False) you can give both 13-valent and 23-valent at the same time if you've got to catch up? Any exceptions?
FALSE! There must be a 1 year gap between 13 and 23 administration.

[EXCEPTION: Immunocompromised, asplenic, CSF leak, and cochlear implant pts may receive 23 at least 8 weeks after 13 administration. Always give 13 FIRST!]
General rule for Pneumococcal vaccination:

"__ before 60, __ after 65"
"13 before 60, 23 after 65"
HPV vaccination schedule
Aka Gardasil vaccination.

Given to BOTH males and females from ages 9-26 usually given as 3 doses over 6 months.

Remember, it does not increase promiscuity. Give it to everyone because it prevents cervical CA
Zoster vaccination recommendation.

Any CI?
EVERYONE!, regardless of previous chicken pox status

Given AFTER 60 y.o. once

(CI in those with severe immunodeficiency as it is a live attenuated vaccine)
Meningococcus vaccination schedule and indications
Given at age 11 and age 16 for a total of 2 doses

Mandatory for those in close, confined spaces like bunkers/dormitories (i.e. college, military, Hajj participants)
MMRV vaccination schedules
Required for ALL, usually given as 2 doses at age 1 and age 4

(CI in ↓ immune system and pregnantt* patients)
HiB vaccine schedule
Given to ALL children < 5 yo

It's usually in 4 doses during the first year of life.
Tdap contraindication
if the patient developed encephalopathy after previous administration (< 7 days from dose)
What's the difference between DTap and Tdap?
The *D*Tap is a much stronger dose, containing more Diptheria compounds for protection as well as *T*etanus and *a*cellular *p*ertussis. It is a stronger vaccine useful for priD *D*Tap is a much stronger dose, containing more *D*iptheria compounds for protection as well as Tetanus and acellular pertussis. It is a stronger vaccine useful for priming weak immune systems, making it ideal for infants

∴ DTap is a peds vaccine that is given for a total of 5 doses. 3 doses are in the 1st year, and 2 additional doses between 1-44* years old.

Tdap is used later, primarily for Tetanus prevention beginning at age 10 (aka adolescence) and is boosted q 10y for a total of 3 lifetime doses.

(Note: during adolescence, can give Td booster but you still need 3 lifetime doses of Tdap)
If you get a dirty wound, and you have already received 3 doses of Tdap in your lifetime. What is the management?
"Dirty" wound with documented 3 doses of Tdap:

- If it has been < 10 years since your last Tdap shot, simply clean and dress the wound. No additional stuff needed.

- If it has been > 10 years since the last Tdap shot, you will need a Td booster

(Note: CDC states that "if you have opportunity to give Tdap, give it." Therefore you can use Tdap in lieu of Td. Also, if ≥ 3 lifetime doses, no TIGG* needed.)
If you get a dirty wound, and you have NOT gotten the 3 lifetime doses of Tdap. What is the management?
"Dirty" wound with < 3 documented doses of Tdap:

- If it has been < 5 years since last Tdap shot. Give a Td booster

- If it has been > 5 years since last Tdap shot. You have to give Td booster + TIG

(Note: CDC states that "if you have opportunity to give Tdap, give it." Therefore you can use Tdap in lieu of Td)
Hepatitis _ gets 2 doses of vaccine. Hepatitis _ gets 3 doses of vaccine.

Pick up where you left off in childhood to get the adequate numbers needed.
Hep A = 2 doses

Hep B = 3 doses
If anaphylactic reaction occurs when the patient is given IM Flu vaccine, what should you offer?
Intranasal Flu vaccine, under supervision though.

Remember that the above is live, attenuated; therefore, don't go giving it to people with ↓ immune systems.
Flu vaccine recommendations?
EVERYONE. Period.

HC workers should get it before winter months.

Get it annually.
(True/False) If a patient's reaction after getting IM influenza vaccination is only a skin rash, you can continue to use the IM vaccine?
True, but remember that you need to observe the patient for 30 min before letting them out of the office.
[Vaccine Type]
MMR, Sabin (oral) polio, VZV, Smallpox, Yellow fever, Typhoid (oral), Rotavirus, Fransciscella tularensis, and influenza (intranasal)
Live, attenuated
[Vaccine Type]
Rabies, influenza (IM), Salk (IM) polio, HAV, Vibrio cholerae, Japanese encephalitis
Inactivated (killed) vaccines
[Vaccine Type]
HBV (HBsAg), HPV (6, 11, 16, 18), and Borrelia burgdorferi (outer surface protein)
Recombinant vaccines
[Vaccine Type]
Tetanus, Diptheria, Pertussis
Toxoid vaccines
[Vaccine Type]
H. influenza, N. meningiditis, Pneumococcal, Typhoid (injected)
Subunit vaccines.

(NOTE: Pneumo-23 is *NOT* conjugated, and will NOT stNOT: Pneumo-23 is *NOT* conjugated, and will *NOT* stimulate helper T-cells. Pneumo-13 is the opposite)
Adenovirus vaccination can be given as enteric-coated capsules, making it a one of kind
Live, pathogenic vaccine
Besides having frank anaphylaxis, these (2) populations should NOT be given live, attenuated vaccinations.
Immunocompromised and pregnant
_______ is the ONLY live, attenuated vaccine that can be given to HIV(+) patients. When can it be given safely?
MMR vaccine.

HIV⊕ patients need to have CD4 count > 2000* to have it administered. Anything less would be a contraindication.
Patient's that have an egg allergy should avoid which particular vaccination
Yellow fever
Probability that test results will be positive in patients with disease
Sensitivity
Probability that test results will be negative in patients without disease
Specificity
Probability that a patient with a positive test actually HAS disease
PPV
Probability that a patient with a negative test actually DOESN'T have disease
NPV
The number of newly reported cases of disease in a given time, divided by the total population
Incidence
The number of existing cases of disease divided by total population at a given time
Prevalence
(True/False) Prospective studies are more prone to bias than retrospective studies.
FALSE

Prospective is less prone to bias than retrospective
(True/False) Interventional studies are less prone to bias than observational studies.
True
Gold standard of experimental study.
Randomized Control Trial.

This study uses intervention and control groups, tracks disease outcomes, and uses Odds Ratios
Observational studies cannot establish __________
CANNOT establish causation (only correlation)
Observational study that provides qualitative data presented in a narrative
Case Series
Observational study that provides a RETROspective snapshot of disease and exposure in a given time; usually asking a group of people a single question ONCE (basically utilizing...)
Cross-Sectional

(utilizes dz prevalence)
Observational study that is comparing the same group of people over time. In essence, it is multiple cross-sectional studies; you ask your group of people a single question over different periods of time. (therefore assessing...)
Longitudinal

(assessing ∆ prevalencee*)
Observational study that is PROspective and seeks to compare groups based on exposure status (exposed vs unexposed) while tracking disease outcome over time. This study utilizes _________ __________.
Cohort study, which utilizes Relative Risk
Observational study that is RETROspective and seeks to compare groups based on disease status (with dz vs without dz) and the correlation of multiple exposures that may relate to the disease state. This study utilizes ________ ___________.
Case Control study, which utilizes Odds Ratio
___________ study requires a large population, and cannot be used to study rare disease
Cohort study
_________________ study needs fewer patients, so it is good for rare disorders
Case-control study
A test with high __________ is used to rule OUT disease.
SeNsitivity.

("SN-N-OUT")
A test with high ____________ is used to rule IN disease
SPecificity

("SP-P-IN")
(True/False) Both sensitivity and specificity take into consideration the pre-test probability of disease.
FALSE

They both DO NOT take pre-test probability into consideration.

∴ They cannot be used as measurements of post-test probabilityy* of disease
PPV is used to rule ______ disease
PPV = rule IN disease
NPV is used to rule _______ disease
NPV = rule OUT disease
Tests with high ___________ tend to have high PPVs
Specificities (aka rarely FP)
Tests with high ___________ tend to have high NPVs
Sensitivities (aka rarely FN)
If there is an ↑ PRE-test probability of disease for the samee* test with the same SP and SN. What happens to the PPV and NPV?
↑ pre-test probability (aka prevalence):

- ↑ PPV
- ↓ NPV
If there is an ↓ PRE-test probability of disease for the samee* test with the same SP and SN. What happens to the PPV and NPV?
↓ pre-test probability (aka prevalence):

- ↓ PPV
- ↑ NPV
Likelihood Ratios (LRs) are calculated strictly based upon (2) and they (do/do not) take into account pre-test probability. This makes them more portable between studies.
LRs are calculated based upon sensitivity and specificity and they do not take into account pre-test probability.

⊕LR = sensitivity/(1 - specificity)

⊗LR = specificity/(1 - sensitivity)
LRs of 1-4 indicate the test will be?
Basically terrible. They wouldn't be useful for changing pre-test probabilities at all.
LRs of 5-10 indicate the test will be? What about LRs of >10
LRs of 5-10 indicate a good test, but LRs > 10 are amazing

Both of the above will significantly change pre-test probability of disease.
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