Statistics and Screening

Question 1

What is the formula for +LR and -LR?

Answer 1

LR+= sens/(1-spec)

LR-=(1-sens)/spec

remember specificity always goes in the denominator

Question 2

How are +LRs>1 interpreted?

Answer 2

LRs of 2, 5, and 10 increase disease probability by 15%, 30%, and 45%

Question 3

How are +LRs interpreted?

Answer 3

LRs of 0.5, 0.2, and 0.1 decrease disease probability by 15%, 30%, and 45%

Question 4

Convert odds to probability

Answer 4

probability=odds/(odds+1)

ex: 2:1 odds means 2/3=66% probability

Question 5

Convert probability to odds

Answer 5

odds=prob/(1-prob)

ex: 66% probability means .66/.33= 2:1 odds

Question 6

Overdiagnosis is a form of what kind of bias?

Answer 6

length-time bias. Because indolent things are picked up, which never would have harmed the patient. So of course it looks like screening has a better outcome.

Question 7

What 6 things does the USPTF recommend AGAINST for screening?

Answer 7

1. coronary artery stenosis (I guess stress test?)
2. CAD in lowe risk patients
3. testicular cancer
4. ovarian cancer
5. pancreatic cancer
6. bladder cancer

Question 8

who should be screened for depression?

Answer 8

anyone with access to appropriate follow-up

Question 9

who should be screened for diabetes?

Answer 9

Some say: Only patients with HTN or DLD
Other say: All age>45 yrs every 3 yrs

USPSTF: adults aged 40 to 70 years who are overweight or obese

Question 10

who should be screened for colon cancer?

Answer 10

everyone age 50-75 yrs

Question 11

who should be screened for DLD?

Answer 11

Book says…..
if risk factors: >20 yrs old

Online says…
if man with no RF: >35 yrs old
if woman with RF: >45 yrs old

Question 12

who should get a mammogram?

Answer 12

age>40 yrs old every 2 yrs

Question 13

who should get a pap smear?

Answer 13

women age 21-65 every 3 yrs

Question 14

who should get screened for chlamydia?

Answer 14

sexually active women age 24 years and younger and in older women who are at increased risk for infection

Question 15

who should get screened for HIV?

Answer 15

1x screening for all aged 15 to 65 years

Question 16

who should get a DEXA scan?

Answer 16

women>65 yrs old
men>70
adult with fracture
women >60 yrs old with RF

Question 17

who should get AAA screening?

Answer 17

1x ultrasound screen for men age 65-75 yrs with a smoking history

Question 18

when do you give Td booster?

Answer 18

No wound: every 10 years

Presenting with a wound:
Clean wound: Last had it >10 yrs ago
Big wound: Last had it >5 yrs ago

Question 19

Which adults get Tdap?

Answer 19

1x dose for those 19-64 years old

Question 20

who should NOT get the MMR?

Answer 20

pregnant women, immunocompromised patients, or those born before 1957 (have immunity to measles and mumps)

Question 21

who should get HPV vaccine?

Answer 21

females 9-26 yrs old. Males can get it too, but not as strong a recommendation

Question 22

is hep B vaccine safe for pregnant women?

Answer 22

yes. But the MMR and the varicella are not.

Question 23

what age adult should get the zoster vaccine?

Answer 23

> 60 yrs old, regardless if have had shingles outbreak or not

Question 24

who should get meningococcal vaccine?

Answer 24

young adults, or those without a spleen, or those traveling to endemic area

Question 25

What is the timeline for grief vs. depression after a loved one dies?

Answer 25

Symptoms of depression for >2 weeks at >2 months out = depression
OR
Symptoms of anger, intense longing, thinking about the person, etc at >6 months out = complicated giref

Question 26

Difference between length time bias and lead time bias

Answer 26

Lead-time: Same person dies at same age, but “death from diagnosis” is longer because you picked it up earlier

Length time: Pick up more indolent cases in your group, so outcomes seem to improve

Question 27

Which patients need TWO pneumococcal vaccines after age 65? (the second after 5 years)

Answer 27

1. Asplenia
2. CKD
3. Cancer
4. Immunocompromised