Evidence Based Medicine 1

Front 1

SHould you ONLY follow EBM?

Back 1

no, you must still use clinical expertise to tailor tx for your indiidual pts

Front 2

what kind of knowledge should you use alongside EBM?

Back 2

pathphysiology knowledge

Front 3

what would my practice look like with EBM?

Back 3

always modifying diagnostic and tx techniques according to recent literature.

not relying on dogma

throwing "rules" out the window

Front 4

What is POEM and DOE?

Back 4

POEM- patient oriented evidence that matters- pay attention to this because it deals with patient outcomes and regular practice

DOE- disease oriented evidence- don't pay much attention because it is premature research and may not be related to daily practice and hasn't tested for pt outsomes yet

Front 5

what is the cochrane collaboration?

Back 5

an INTERNATIONAL group that conducts systematic reviews to discover POEMs that can change practice

Front 6

give a baby example of when pathophysiology reasoning got trumped by EBM

Back 6

drs used to recmmend laying babies on their stomach to prevent aspiration while sleeping, but research found that this actually dramatically raised SIDS

Front 7

give an example of when a DOE showed something to be good, but a POEM showed it to be bad.
what were they measuring?

Back 7

ecainide and flecainide showed decrease in ventricular arrythmias (DOE measured arrythmmia effect to be good), but pts on these drugs died more often (POEM measured mortality to be bad)

Front 8

Randomised controlled trial (RCT)
what is it?

Back 8

trial where people are randomly assigned to control or intervention group

Front 9

what does risk mean?

Back 9

probaility of a bad outcome

Front 10

What is ARR?
give an example if the intervention group had 12% bad outcomes and the control had 20%

Back 10

Absolute Risk Reduction - is 8%
overall how much less bad outcomes happens with intervention?

Front 11

What is NNT
give an example if the intervention group had 12% bad outcomes and the control had 20%

Back 11

Number Needed to Treat
100/8 = 12.5

how many people do you need to treat before one person would theoretically be saved from the intervention?

Front 12

How are ARR and NNT related to one another?

Back 12

they are inverse of one another

Front 13

What is relative risk?
give an example if the intervention group had 12% bad outcomes and the control had 20%

Back 13

the risk in the intervention over the risk in the conrol

.12/.20 = .6

Front 14

What RR would be good, bad, or neutral

Back 14

below 1 is good
1 shows no effect
above 1 is bad

Front 15

what does it mean if I say the RR of a drug was 1.5?

Back 15

you will be 50% more likely to have a bad outcome if you take the drug

Front 16

what is an odds ratio?
how do you calculate it?

Back 16

the odds that an intervention created a bigger risk

set up a 2x2 table comparing people that did get bad outcomes and those that didn't
multiply each groups numbers and divide between groups

Front 17

is odds ratio and RR the same thing?

Back 17

kind of. they go in the same relative direction, but the numbers don't work out to be the same

Front 18

what is cumulative incidence/risk?

Back 18

the answer to the question "how far has the disease spread in a certain time interval"

measures freq of disease

new cases/population being measured = % cumulative risk

Front 19

highest cumulative risk you can have?

Back 19

100%

Front 20

what kind of calculation is cumulative risk needed for?

Back 20

relative risk

Front 21

what happens in a cohort study?

Back 21

you follow a bunch of undiseased people over time and see if they develop the disease eventually.

people are split into exposed to variable of interest vs not exposed groups.

Front 22

two major kinds of cohort studies? what is the difference?.

Back 22

prospective and retrospective

has the disease outcome occured at the time of the study initiation?

Front 23

what is a clinical trial?

Back 23

when you randomly assign people to an exposure vs nonexposure group to test outcomes

Front 24

What is a community trial?

Back 24

when you randomly assign whole communities rather than individuals to an exposure

ex. comparing communities who are given fluoridated vs non flouridated water for outcomes.

Front 25

why would you do a clinical vs community trial?

Back 25

clinical- for an intervention that would eventually be applied to individuals (i.e. drugs)

community - for an intervention that would eventually be applied to communities like flouridating water

Front 26

what is the difference between incidence and prevalence?

what are they each used to say?

Back 26

incidence- how many new cases happened in a given time period
--used to calculate your risk of developing a disease

prevalence- how many people have something in a given snapshot
---used to calculate your likelihood of having a disease

Front 27

give an example of a low incidence and high prevalence

Back 27

DES has somewhat of a prevalence, but no incidence over the last couple decades

Front 28

difference between morbidity and mortality?

Back 28

morbidity- illness/disease
mortality- death

Front 29

how would you go about reporting mortality? give an example.

Back 29

83 per 100,000

if 83 out of 100,000 people with lung cancer died in a year.

Front 30

is a person either morbid or not?

Back 30

no, they can have co-morbidities

Front 31

What is an open clinical trial?

Back 31

a clinical trial where there is no control group

Front 32

what is a double blind vs triple blind study?

when would you use a triple?

Back 32

double- subject and observer don't know who has tx
triple- also the person analyzing the data doesn't know

triple is used when the data is "soft" or can be interpreted multiple different ways

Front 33

what is a crossover clinical trial?

Back 33

where the participants receive both treatments consecutively, but do not know in which order

Front 34

what is a pilot study?

Back 34

a study condiucted on a small scale to see if it should be conducted for real.

fleshes ot problems and tells you how you should design the real study

Front 35

what is a observational descriptive vs observational analytical study?

when is each performed?

Back 35

both require no intervetnion

descriptive is when we don't have much info
analytic is when we have enough info to formulate a hypothesis to analyze the data to test

Front 36

NOW WE DO EBM VIA DIT!
what are case-control studies? dissect

Back 36

when we look at people who have the disease (case)
and people who don't have the disease (control)

and find out what the case has/does that the control does not

Front 37

what conclusions can you draw from case control studies?

Back 37

risk factors ASSOCIATED with a disese

no causation

Front 38

Who may do a case cotnrol study?

Back 38

CDC

Front 39

What are two qualities about a case control study?

Back 39

observational and retrospective

Front 40

opposite of observational?

Back 40

experimental

Front 41

what exactly does cohort mean?

what does a cohort study have to involve in terms of peritciipants?

Back 41

a group of people with something in common (exposure or non exposure)

you need at least two cohorts for a cohort study

Front 42

what is the difference between odds ratio vs relative risk?

when would you use each?

which is better?

Back 42

odds ratio is just an approximation of relative risk when you don't know the exactl risk percentage (total population of interest and their outcomes)

relative risk is better

Front 43

what is the basic calculation for risk vs odds?

Back 43

Front 44

what is the risk vs odds of rolling a 2 in a 4 sided die?

Back 44

risk- 25% or 1 out of 4
odds- 33% or 1 to 3

Front 45

why are odds used in horse racing?

Back 45

it is a fair payout where if you multiply the amount of the bet by the odds, you are expected to break even

Front 46

when does odds ratio approximate relative risk and when can it not?

Back 46

only when the risk is small

Front 47

if teens normally have 80% of them grow taller and an elixir increases that by 10%, what is the relative risk vs the odds ratio? do the math

Back 47

RR- .9/.8 = 1.125 = 12.5% more likely than control to grow taller

OR- 90:10/80:20 = 9/4 = 2.25 = odds are more than 2 times greater

sooo misleading!

Front 48

how you you put a RR of .8 into words?

Back 48

the risk of developing a disease was decreased by 20% in persons exposed compared to those unexposed

Front 49

2 ways to put into words a RR of 3.3

Back 49

1. the risk of developing a disease was 230% greater than the unexposed group
2. the experimental grop was 3.3 times more likely to develop the disease than the unexposed group

Front 50

when may a RR of 3 be significant vs not significant.

Back 50

depends on how they first started out.

if they started out at a high baseline of risk, then it is impressive (ex. 30% --> 90%)

but .1% to .3% is not impressive

Front 51

between RCT, Cohort, and Case-Control, rank them in order of most to least prone to bias

what sort of RR or OR should we want from each to be impressed?

Back 51

most: case control (OR>4), cohort(RR>3), RCT (even a little)

Front 52

what can case-control studies only be measured by? why?

Back 52

odds ratio because for a given risk, you only know the # of people with it who got the disease vs didn't get it.

you don't know the true population

Front 53

what is the difference between a case control study and a retrospective cohort study>

Back 53

in case control investigator splits individuals by disease status whereas in retrospective cohort, investigator splits study individuals by their exposure status.