Evidence-based Practice

Question 1

What is the aim of critical appraisal?

Answer 1

To understand strengths, weaknesses and potential for bias in research before you apply it

Question 2

List 4 considerations used to determine if evidence is valid

Answer 2

1. Is it clinically significant?
2. Is it clinically important?
3. Is the evidence applicable
4. Is the evidence relevant?

Question 3

What are the 4 tools in the Critical Appraisal Skills Program (CASP)?

Answer 3

1. Systematic Reviews
2. RCTs
3. Case Control Studies
4. Cohort Studies

Question 4

List 2 screening questions you should ask when appraising systematic reviews

Answer 4

1. Did the review address a clearly focused question?
2. Did the author look for the right type of papers?

Should answer YES to both

Question 5

List 8 detailed questions you should ask when appraising the evidence from systematic reviews

Answer 5

1. Were all important, relevant studies included?
2. Did the author do enough to assess quality of included studies?
3. If results were combined, was it reasonable to do so?
4. What were overall results of the review?
5. How precise were results?
6. Do results apply to population?
7. Were all important outcomes considered?
8. Are the benefits worth the harm and cost?

Question 6

What does the appraisal method RAMMbo stand for?

Answer 6

R - Recruitment

A - Allocation

M - Maintenance

M - Measurement

b - blind testing
o - objective and standardised measures

Question 7

Give 1 question you should ask when appraising a models Recruitment (RAMMbo)?

Answer 7

1. Are Ps representative of population?

Question 8

Give 2 question you should ask when appraising a models Allocation (RAMMbo)?

Answer 8

1. Was the assignment to treatments randomised?

2. Were the groups similar at the start of the trial?

Question 9

Give 2 question you should ask when appraising a models Maintenance (RAMMbo)?

Answer 9

1. Were the individuals in the groups treated equally?

2. Were the outcomes ascertained and analysed for most Ps?

Question 10

Give 2 question you should ask when appraising a models Measurements (RAMMbo)?

Answer 10

1. Were the Ps and clinicians blinded?

2. Were measurements objective and standardised?

Question 11

What is the CONSORT Statement?

Answer 11

An evidence based, minimum set of recommendations for reporting RCTs.

A 25 item checklist

Question 12

What does CONSORT stand for?

Answer 12

CONsolidated
Standards
Of
Reporting 
Trials

Question 13

Is statistical significance the same as clinical significance?

Answer 13

No

Question 14

What is clinical significance?

Answer 14

The practical importance of a treatment effect

Whether it has a real genuine, palpable, noticeable effect on daily life

Question 15

When is a treatment effect clinically relevant?

Answer 15

A small therapeutic benefit may be important for a highly fatal disease, but may not be enough to justify a new intervention in a disease with a good prognosis

Question 16

What does clinical importance require?

Answer 16

A substantial change in an outcome that matters

Question 17

What calculations can you use to ascertain clinical significance?

Answer 17

1. Event rare
2. Absolute and relative rate
3. Number needed to treat

Question 18

What is the Absolute Risk of a disease?

Answer 18

Your own risk of developing the disease over a period of time

Expressed as 1 in 10, 10%, or 0.1 risk

Question 19

What is Relative Risk?

Answer 19

Used to compare the risk in two different groups of people

Eg. Smokers have a higher risk of lung cancer relative to non smokers

Question 20

What is the Event Rate?

Answer 20

The proportion of people in control/treatment conditions of an experiment who experience a particular event (response to drug)

Question 21

Name the 2 types of Event rates

Answer 21

1. CER- Control event rate

2. EER - Experimental Event rate

Question 22

What is Number Needed to treat?

Answer 22

The number you need to treat to prevent a bad outcome

Question 23

What is the Absolute Risk Reduction (ARR)?

Answer 23

The AAR is the difference between the event rates in the 2 groups or the size difference between 2 treatments

Question 24

What does the AAR tell you?

Answer 24

The AAR tells you the size of the treatment effect

Question 25

How do you calculate AAR or Absolute Risk Reduction?

Answer 25

CER - EER (Control event rate minus experimental event rate) Difference between event rates in the 2 groups

Question 26

If 20% of patients die with no treatment (A) and 15% die with treatment (B), what is the Absolute Risk Reduction?

Answer 26

5% CER-EER 0.20-0.15 =0.05 or 5% This means that for every 100 patients enrolled in the treatment group about 5 deaths would be prevented

Question 27

What is another way of expressing the Absolute Risk Reduction?

Answer 27

The Number Needed to treat NNT The number of patients that need to be treated in order to have an impact on 1 person to prevent additional bad outcomes

Question 28

How do you calculate the Number Needed to Treat NNT?

Answer 28

NNT= 1/ARR Number Needed to Treat = 1 divided by the Absolute Risk Rate

Question 29

What is the Number Needed to Treat in a clinical trial of a drug preventing migraines if 2 out of 100 people taking the drug experience migraines (2%) compared to 4 out of 100 taking a placebo?

Answer 29

ARR = CER- EER =0.02 NNT = 1/ARR = 1/0.02 = 50 The number you need to treat for 1 person to benefit is 50

Question 30

What is Relative Risk Reduction RRR?

Answer 30

RRR is the difference in event rates between 2 groups expressed as a proportion of the event rate in the untreated group The relative or proportional difference

Question 31

What is the Relative Risk Reduction if 20% of patients die with no treatment A and 15% die with treatment B. ?

Answer 31

There is a 5% Absolute Risk Reduction with treatment B. The Relative Risk Reduction is 25% RRR = (CER - EER)/CER = (0.2 - 0.15)/0.2 = 25 This means that the disease was reduced by 25% in the treatment group compared with the Control group

Question 32

What are the similarities between Absolute Risk Reduction ARR and Relative Risk Reduction RRR?

Answer 32

Both calculations explain the same difference BUT in different ways

Question 33

What are the differences between Absolute Risk Reduction ARR and Relative Risk Reduction RRR?

Answer 33

ARR explains the simple difference between rates RRR describes the Relative or proportional difference

Question 34

What is the Odds Ratio (OR)?

Answer 34

Odds Ratio is a measure of association between an exposure and an outcome. The OR represents the odds that an outcome will occur given a particular exposure compared to the odds of the outcome occurring in the absence of that exposure

Question 35

What is the Odds Ratio OR if 100 patients with lung cancer and 100 patients without lung cancer were recruited into a study and questioned about their tobacco use over the past 20 years. 90 with lung cancer and 10 without reported smoking?

Answer 35

OR= exposed to smoking & have cancer / exposed to smoking and don’t have cancer Calculate cross product OR = 90x90/10x10=81 If you have lung cancer you’re 81 times more likely to have smoked than if you don’t have cancer

Question 36

What is the standard effect size?

Answer 36

Provides an indication of the size of treatment effects is the magnitude sufficient to be of practical relevance?

Question 37

What calculation is used to find effect size?

Answer 37

Cohen’s d Cohen’s d = (M1-M2)/SDpooled Take the mean difference between 2 treatments and divide by the pooled variance

Question 38

How do you interpret standard effect size?

Answer 38

0. 2 = small 0. 5 = moderate 0. 8 = large

Question 39

List 3 ways to assess whether results apply to your clients

Answer 39

1. Assessment of their individual baseline risk 2. Judgment about whether the evidence can be extrapolated to your client 3. Understanding of factors that may increase the benefits or harm their experience

Question 40

List 4 considerations when applying evidence results

Answer 40

1. Do the results apply to my client? 2. What are my clients values and preferences? 3. Can the practice be implemented in this setting? 4. How can I help my client make a decision?

Question 41

What are the benefits of qualitative research?

Answer 41

Provides guidance in deciding whether findings apply to clients Determines how people feel about things and what their experiences were

Question 42

What is the efficacy of a treatment determined by?

Answer 42

Clinical trials which many variables are carefully controlled to demonstrate that the relationship between the treatment and outcome are relatively ambiguous

Question 43

What do efficacy studies emphasise?

Answer 43

Internal validity of the experiment * controlling types of Ps * using manuals for standardisation * training and monitoring therapists * controlling number of treatment sessions * random assignment and blind testing

Question 44

What do effectiveness studies seek to examine?

Answer 44

The outcomes of interventions under circumstances that are similar to the real world (external validity)