Prognostic Studies

Question 1

Area under the curve

Answer 1

measure of the accuracy of a quantitative diagnostic test

Question 2

ROC Curves Axis

Answer 2

Y = true positive
X = false positive

Question 3

ROC Curve

Answer 3

a plot of sensitivity against 1=specificity, used to determine the most effective cut-off score to make a diagnosis/prognosis

defines cutoff scores, helps predict the outcome of interest

the more area under the curve, the better it is at predicting the outcome of interest

Question 4

What is the significance of RR/OR?

Answer 4

RR and OR are estimates and are subject to error

you need to have a p value or confidence interval to determine that the result is not due to chance

Question 5

Odds Ratio

Answer 5

proportion of participants who have the outcome of interest compared to the proportion of participants who do not have the outcome of interest

comparing columns

Question 6

Relative Risk

Answer 6

proportion of participants who have the risk factor and the outcome compared to the proportion of participants without the risk factor who have the outcome

comparing rows

Question 7

Relative Risk ratio calculation

Answer 7

(Outcome +, Risk factor +)/ (Outcome +, Risk factor +) PLUS (outcome -, risk factor +)

DIVIDED BY

(outcome +, risk factor -)/(outcome +, risk factor -) PLUS (outcome -, risk factor -)

Question 8

Clinical Significance

Answer 8

<1 = decreased risk or odds of developing outcome

(>) 1 = increased risk or odds of developing outcome

= 1, 50/50 chance

Question 9

Risk Ratio

Answer 9

predicts the probability of an outcome when a risk factor is present vs not present

used in longitudinal cohort studies

Question 10

Logistic Regression

Answer 10

used to predict a categorical outcome variable

Ex: fall vs no fall, discharge vs no discharge

Question 11

Multiple Regression

Answer 11

used when there are multiple variables contributing to an outcome variable or when the outcome is a continuous variable

uses a weighting process

y=a+bx1+bx2+bx3…

Question 12

B is equivalent to

Answer 12

slope of the line
regression coefficient

Question 13

A is equivalent to

Answer 13

intercept of the regression line at y
also known as a regression constant

Question 14

Y is equivalent to

Answer 14

outcome of interest or the value you are trying to predict

Question 15

Simple Linear Regression

Answer 15

exam of two variables that are linearly related to determine how well a variable predicts (x) an outcome (y) variable

can be positive or negative
y = a+bx

Question 16

Standard error of the estimate

Answer 16

represents the average error of prediction for the regression equation

Question 17

Confidence Intervals

Answer 17

provides info about the accuracy of the prediction

Question 18

P-value

Answer 18

estimates the probability that chance contributed to the prognostic equation

does not indicate clinical meaningfulness

Question 19

r²

Answer 19

coefficient of determination

represents the robustness of the regression model

proportion of variance that is shared by two variables

Question 20

Regression

Answer 20

Used to make predictions from one or more variables about the outcome of interest

uses a regression analysis to find the line of best fit to predict the outcome variable

the closer R2 is to 1, the more robust the prediction

Question 21

Correlation can be useful for

Answer 21

developing prediction or prognostic models

Question 22

Correlation does not equal

Answer 22

causation

Question 23

Very high correlation

Answer 23

.9 - 1.0

Question 24

High correlation

Answer 24

.7 - .89

Question 25

Moderate correlation

Answer 25

.5 to .69

Question 26

Low correlation

Answer 26

.26 to.49

Question 27

Little or no correlation

Answer 27

0 to .25

Question 28

Negative correlation

Answer 28

as one variable increases, the other decreases

Question 29

Positive correlation

Answer 29

as one variable increases, so does the other

Question 30

Correlation

Answer 30

a measure of the extent to which two variables are associated. calculated as a correlation coefficient can either be positive or negative

Question 31

Interpret the results of prognostic study

Answer 31

what statistics were used to determine the prognostic statements? Were the stats appropriate (correlation/regression)?

Question 32

Study Process

Answer 32

Were evaluators masked/blinded to reduce bias? Was the study time frame long enough for the participants to experience the outcome of interest? Was the monitoring process appropriate? Were all participants followed to the end of the study?

Question 33

Outcome measures and factors associated w/these measures

Answer 33

Were end points clearly defined? Are the factors associated with the outcome well justified in terms of the potential for their contribution to prediction of the outcome? should be systematic, precise, relevance, defined, reliable, valid

Question 34

Determining quality of prognostic study

Answer 34

study design study sample outcome measures and factors associated w/measures study process

Question 35

Is there a defined, representative sample of pts assembled at a common point that is relevant to the study question?

Answer 35

Were they randomized into groups vs part of a cohort or case-control group? Were they assembled at a common point? Are there enough pts? Study participants must not already have the study outcome

Question 36

Types of prognostic studies

Answer 36

Cohort Case Control Cross-Sectional

Question 37

Classification measures

Answer 37

sensitivity specificity predictive values clinicians need to verify the chosen thresholds is relevant for their pt

Question 38

Discrimination is the same as

Answer 38

accuracy

Question 39

Calibration is the same as

Answer 39

reliability

Question 40

Performance measures

Answer 40

Prognostic Models must demonstrate: Calibration, Discrimination without these, model may be inaccurate and can mislead decision-making of PT

Question 41

Clinical Decision Rules

Answer 41

suggest a course of action treatment-effect modifiers are used to build a CDR guides clinicians in their decision-making and care pathways by predicting treatment response represented as regression/classification tree, score chart rules, or survival groups/meta-models

Question 42

Clinical Prediction Rules

Answer 42

estimates the probability of future outcomes prognostic factors help to build it should be consistent to be helpful presented as regression formula/calculator, nomogram or table/score chart

Question 43

Treatment-Effect Modifiers

Answer 43

Characteristics that predict a pt's response to a treatment influence the relationship between an intervention and an outcome used to create clinical decision rules

Question 44

Prognostic factors

Answer 44

characteristics found in individuals with a disease can influence the course of the disease used to create clinical prediction rules

Question 45

Risk Factors

Answer 45

characteristics found in individuals that are healthy factors that increase the risk of developing a health condition important to PTs who have an interest in prevention

Question 46

Dimensions of Prognosis

Answer 46

Risk Factors Prognostic Factors Treatment-effect modifiers

Question 47

Why is it beneficial to target prognostic factors?

Answer 47

improve treatment decision-making process personalize rehab approaches enhance pt outcomes help better align clinical practice with value-based care principles

Question 48

Contemporary view of prognosis

Answer 48

prognostic-related findings must inform clinical decision making to enhance patient health outcome

Question 49

Traditional prognosis method

Answer 49

prognosis is driven by pathoanatomical diagnosis to guide treatment and guide prognosis. has variable outcomes

Question 50

Prognosis definition

Answer 50

predicting which patient will have the best outcome or respond to a particular treatment traditional and contemporary views