Intervention

Question 1

What are the barriers to EBP?

Answer 1

• lack of time
• lack of training
• lack of quality research evidence

Question 2

How does CrowdCARE address the barriers to EBP?

Answer 2

• lack of time –> shares critical appraisals
• lack of training –> provides tutorials on EBP and critical appraisal
• lack of research evidence –>
  spreads critical appraisal load

Question 3

What is the purpose of critical appraisal?

Answer 3

• Determines quality of evidence of a study

- enables us to give different weight to different studies when making clinical decision

Question 4

3 basic questions to be answered in critical appraisal?

Answer 4

1) Are the results valid? (Internal Validity)
2) Are the results of value? (Clinical Significance)
3) Do the results help in caring for my Px? (External Validity)

Question 5

Construct a Clinical Question for-
What are the search terms?
You are an optometrist working in Melbourne. In your practice, you have some teenagers with myopia who display rapid progression. You usually just recommend good visual hygiene. During a consultation today, one parent mentioned a news report about a ‘breakthrough’ from overnight orthokeratology lenses on myopia progression, and asked if you can prescribe them. You search the literature to see if there is any evidence of their effectiveness.

Answer 5

Patient: teenager with myopia

Intervention: orthoK lenses

Control: No orthoK lenses

Outcome: slowing myopia progression

Question: Do OrthoK lenses reduce myopia progression compared to no orthoK lenses in teenagers with myopia

Search terms: myop* AND orthokeratology AND progres*

Question 6

What is the gold standard study for Intervention Questions?

Answer 6

Randomised Control Trials

Question 7

What is a Randomised Control Trial (RCT)?

Answer 7

• randomly divide participants into 2 groups
• one group gets intervention, other group is control (no intervention)
• only difference b/w 2 groups is intervention so any differences can be attributed to intervention

Question 8

Are all Randomised Control Trials good quality?

Answer 8

no not all equal- must assess quality (Appraise)

Question 9

What methodology is used to critically appraise RCT?

Answer 9

PEDro database scale

Physiotherapy Evidence Database scale

Question 10

How does PEDro work?

Answer 10

11 criteria, 10 scored to give total of 10

Question 11

Explain the steps of appraising Randomised Control Trials:

Answer 11

check word doc`

Question 12

What question in PEDro is not used to calculate PEDro score in RCT?

Answer 12

1. Eligibility criteria specified

Question 13

What is external validity?

Answer 13

Do the results help in caring for my Px?

Question 14

What is internal validity?

Answer 14

Are the results valid?

Question 15

What is statistical significance?

Answer 15

Are the results of value?

Question 16

What ist he purpose of 1. Eligibility criteria specified?

Answer 16

External validity- are results applicable to Px?

Not used to calculate PEDro score

Question 17

Do quasi-randomised allocation procedures satisfy randomly allocated criteria?

Answer 17

NO

Question 18

What is quadi-randomised procedures?

Answer 18

e. g. allocation by surname, birthdate, hospital number

- doesn’t satisfy randomly allocated criteria

Question 19

Why is it important that assessors are blind?

Answer 19

they can influence the effect size with their bias

Question 20

Can analysis be done as if participants were in the group they swaped into?

Answer 20

NO- biases the group allocation

- measure as if participant received treatment they were allocated to

Question 21

What do RCT measure?

Answer 21

average effects of an intervention

• SIZE of intervention (difference in means b/w control and experimental group)
• PRECISION of intervention effect (SD, SE, CI)

Question 22

What is a type I error

Answer 22

Probability of false positive (falsely rejecting null hypothesis)
- cutoff is p<0.05

Question 23

What is power of a study?

Answer 23

Ability to detect differences

Question 24

How can we increase the power of a study?

Answer 24

increasing participants

Question 25

Why do we want a stronger power of study?

Answer 25

Greater ability to detect differences

Question 26

Usual convention of power:

Answer 26

80% chance of detecting differences (20% chance of type II error)

Question 27

What is a Type II error?

Answer 27

probability of falsely accepting null hypothesis

• due to POWER of study wanting 80% chance of detecting differences
• so 20% chance of not detecting differences and falsely accepting null hypothesis

Question 28

Type I error vs Type II error

Answer 28

Type I: falsely rejecting null hypothesis (b/c p<0.05)

Type II error: falsely accepting null hypothesis (b/c power = 80%)

Question 29

If we replicate a study with another sample of participants, would we get the same size of intervention effect?

Answer 29

NO (most likely not)

Question 30

Does the size of the intervention effect of a study measure the size of the intervention effect in a population?

Answer 30

NO

Question 31

What are Confidence Intervals?

Answer 31

• how much uncertainty is associated with estimate of intervention effect
  (i. e. precision/accuracy of estimate)
• range of values that true value lies in

Question 32

What does a Confidence Interval of 95% mean?

Answer 32

we are 95% confident that true intervention effect lies between upper and lower limits of CI
- if you repeated experiment, 95% of intervals computed would contain true population value

Question 33

RCT 1. Eligibility criteria were specified

Answer 33

• not added to PEDro score
• satisfied if provides list of criteria to determine whos eligible for study
• used for assess if study applied to your Px

Question 34

RCT 2. Subjects were randomly allocated to groups

Answer 34

participants randomly allocated to group
random not quasi-randomised allocation
- e.g. role of dice - yes
- e.g. based on DOB, surname- NO

Question 35

RCT 3. Allocation was concealed

Answer 35

all individuals in study unaware of allocation

Question 36

RCT 4. The groups were similar at baseline regarding the most important prognostic indicators

Answer 36

• this is the aim of randomisation
• present at least 1 measure of severity of condition in each group measured at baseline and we judge that they are similar
• often in Table 1

Question 37

RCT 5. There was blinding of all subjects

Answer 37

if participants could not know which group they are allocated to

Question 38

RCT 6. There was blinding of all therapists who administered the therapy?

Answer 38

if you believe that therapist (providing treatment) could not know which group participant is allocated to

Question 39

RCT 7. There was blinding of all assessors who measured at least one key outcome

Answer 39

if you believe assessor cant know which group the participant is allocated to

Question 40

RCT 8. Measures of at least one key outcome were obtained from more than 85% of subjects initially allocated

Answer 40

• satisfied if report explicitly states both:
o the number of participants initially allocated to groups
o the number of participants from whom key outcome measures were obtained.
o In trials in which outcomes are measured at several points in time, a key outcome must have been measured in >85% of subjects at one of those points in time.

Question 41

RCT 9. All subjects for whom outcome measures were available received the treatment or control condition as allocated or, where this was not the case, data for at least one key outcome was analysed by “intention to treat”

Answer 41

satisfied if
o analysis is performed as if participants received the intervention they were allocated to.
o report does not need to mention analysis by intention to treat if it explicitly states that all participants received the intervention as allocated.

Question 42

RCT 10. Results of between-group statistical comparisons are reported for at least one key parameter

Answer 42

e.g. p value or Confidence interval

Question 43

RCT 11. Study provides both point measures and measures of variability for at least one key outcome

Answer 43

e.g. SD, SE, CI