Exam Two - Clinical Prediction Rules

Question 1

CPR use a combination of clinical findings to predict:

Answer 1

• presence of a disorder
• likelihood of a treatment outcome
• most likely prognosis

Question 2

What is the goal of CPR?

Answer 2

intended to simplify and increase the accuracy of clinicians’ diagnostic and prognostic assessments

Question 3

CPR is used in combination with….

Answer 3

clinical intuition!
- not a replacement for experience
- reduce the influence of bias in clinical judgements

Question 4

CPRs are especially useful when…

Answer 4

• decision making is complex
• clinical stakes are high
• opportunities exist to avoid unnecessary tests without compromising patient care

Question 5

CPRs quantify what three aspects of our practice?

Answer 5

• diagnosis
• prognosis
• intervention

Question 6

Diagnosis CPRs are frequently designed to maximize _______ in order to better rule ______ the diagnosis

Answer 6

sensitivity
out

Question 7

A _________ diagnostic CPR rules out the fracture

Answer 7

negative

Question 8

A _________ diagnostic CPR does not rule in the fracture because its not __________

Answer 8

positive
specific

Question 9

What question does intervention CPRs seek to answer?

Answer 9

what patient characteristics predict a positive outcome following an intervention?

Question 10

Nearly all intervention CPRs were derived using a ________ study design. Is that good?

Answer 10

“single arm”
nope because there’s no control group or covariation of cause and effect

Question 11

Single arm study designs seek to answer:

Answer 11

what is similar among responders that is different from nonresponders?
- use multiple logistic regression

Question 12

describe pathway of single arm intervention CPR

Answer 12

get group, then measure outcome of interest and possible predictors, then apply intervention, then measure change in outcome of interest, the separate the responders from nonresponders

Question 13

many PT intervention CPRs define “improvement” using the ______- scale

Answer 13

Global Rating of Change (GROC) scale

Question 14

Prognosis CPRs predict the…

Answer 14

natural course of a condition, or its risk for development

Question 15

What is a prognostic factor?

Answer 15

a characteristic that increases or decreases a person’s risk for a certain outcome

Question 16

What are a few types of prognostic factors?

Answer 16

• demographic
• disease-specific
• co-morbidities
• other (insurance, access to healthcare)

Question 17

What are favorable prognostic factors?

Answer 17

• increase likelihood of a positive event or decrease the likelihood of an adverse event

Question 18

What are unfavorable prognostic factors

Answer 18

• increase the likelihood of an adverse event or decrease the likelihood of a positive event

Question 19

nearly all prognostic CPRs were derived using a _____ study design. Is this good?

Answer 19

single arm
yes, it’s good. you aren’t giving an intervention, you’re just letting time pass before you measure outcomes of interest again

Question 20

describe pathway of single arm prognosis CPR

Answer 20

get participants, then measure possible predictor variables, then let time pass (no intervention), then evaluate outcome of interest again, then separate participants into yes/no

Question 21

Why are we concerned with intervention CPRs not having a control group?

Answer 21

with no control group, the identified predictors may simply indicate which patients will get netter over time (alone)

Question 22

If we do a two arm study design for intervention CPRs, what experimental design does it mimic?

Answer 22

RCT
- allows us to test intervention effectiveness
- allows ID of exam findings that predict success with that intervention

Question 23

What are some cons to a two arm study design for intervention CPRs

Answer 23

more subjects, more expensive, more complicated

Question 24

Typically, CPR results include:

Answer 24

1 - sensitivity
2 - specificity
3 - likelihood ratios

Question 25

why is sensitivity useful for intervention CPRs?

Answer 25

negative test results for CPRs with high sensitivity are useful for ruling out a condition or outcome

Question 26

why is specificity useful for intervention CPRs?

Answer 26

positive test results for CPRs with high specificity are useful for ruling in a condition or outcome

Question 27

why are likelihood ratios useful to have for intervention CPRs?

Answer 27

it tells us to what extent we should shift our suspicion for a condition or outcome

Question 28

What is the process of CPR development?

Answer 28

level four - derivation
level three - narrow validation
level two - broad validation
level one - impact analysis

Question 29

step one of derivation of CPR

Answer 29

define the condition or outcome of interest
- consider measurement validity

Question 30

step two of derivation of CPR

Answer 30

compile a list of variables that may predict the condition or outcome of interest (do a lit review, expert opinion, or focus groups)
important that all logical potential predictors are included BUT you need at least 10 subjects per possible predictor

Question 31

T or F: authors need to provide a rationale for predictor variables?

Answer 31

true, because otherwise there is an increased risk of spurious findings that cannot be explained

Question 32

step three of derivation

Answer 32

measurement of predictors variables and track outcomes
consider
- reliability/validity of predictor variables
- subject inclusion/exclusion criteria
- masking to limit bias

Question 33

step four of derivation

Answer 33

collect/analyze data
prospective - measure predictor variables and track subject outcomes
retrospective - evaluate subject outcomes and predictor variables measured previously

Question 34

How do you determine which combination of variables best predicts the outcome of interest?

Answer 34

multiple logistic regression

Question 35

what does narrow validation do?

Answer 35

demonstrates that repeated application leads to the same results in the same setting

Question 36

what does broad validation do?

Answer 36

answers how much you can generalize the CPR

Question 37

what does the impact of the CPR answer?

Answer 37

how helpful is this clinically? does it even matter? who cares? is it useful

Question 38

widespread use of CPR is not technically recommended until:

Answer 38

1 - it has been validated using a prospective design in more than one setting (level 2)
2 - an impact analysis complete (level one). it may show that CPR doesn’t make a difference in patient outcomes or cost

Question 39

When is it acceptable to use CPRs before they’ve been appropriately validated?

Answer 39

1 - under unique clinical circumstances where clinician uncertainty is greater
2 - when the PT setting, presentation, and expertise is similar to the CPR
3 - the magnitude of the effect of the CPR is especially great/high