Critical Appraisal RCT Introduction

Question 1

Assessing Cause and Effect

Answer 1

Each individual is either exposed to the treatment or not
- Assess which ones had the outcome and which ones didn’t

All confounding variables should be kept the same with the only difference being exposure

Question 2

How do biases arise

Answer 2

The only difference in groups should be the experimental intervention
- Biases results from differences in prognostic factors (Patient Characteristics)

Question 3

Steps to practice EBM

Answer 3

1. Ask
2. Acquire
3. Appraise
4. Apply
5. Act and Assess

Question 4

Using pre-appraised resources

Answer 4

Have to be careful as individual studies can be misleading

Question 5

Random Error
- What is it

Answer 5

Random Error: Pure chance causes differences

Question 6

Systematic Error
- What is it

Answer 6

Systematic Error (Bias)
- Underestimation or Overestimation of underlying effects leading to Systematic Deviation from the underlying truth

Question 7

Systematic Error
- Causes

Answer 7

Caused by a feature of the design or the conduct of the research study

Question 8

Random Error vs Systematic Error

Answer 8

Random Error: Graph is spread out and more variable, mean is still the same
- Does not affect the mean

Systematic Error: Graph’s mean deviates from the original
- Affects the mean

Question 9

EBCP definition

Answer 9

Evidence Based Clinical Practice
- Find the best available evidence from systematic reviews and meta analysis
- Determine the strength of those evidences
- How useful it the evidence’s result to the patient

Question 10

Why is it important to study critical appraisals

Answer 10

To be able to assess the quality of studies and deal with misinformation

Be able to tell the difference from high and low quality research

Question 11

Resources to find study synopses and critical appraisals

Answer 11

Wiki Journal Club

ACP Journal Club

RX Files

BMJ Evidence Based Medicine

Question 12

Summary Resources

Answer 12

Dynamed

Lexidrugs

Question 13

Major categories of bias

Answer 13

1. Arises from randomization process
2. Deviations from intended intervention
3. Missing outcome data
4. Measurement of the outcome
5. Selection of the reported result

Question 14

Steps to appraise a therapy trial (JAMA approach)

Answer 14

1. Risk of Bias
2. Clinical Relevance
3. Applicable to Patient Care

Question 15

Risk of Bias
- JAMA Approach

Answer 15

• Was prognostic balance maintained beginning, during the study, and the end

Question 16

Clinically Relevance
- JAMA Approach

Answer 16

How large is the treatment effect
How precise is the estimate of the treatment effect

Question 17

Applicable to Patient Care

Answer 17

• Were the study patients similar to my patients
• Were all important outcomes considered
• Are the benefits worth the harms and costs

Question 18

Understanding Confidence Intervals
- 1.43 [0.51,4.05]

What does 1.43 mean

Answer 18

1.43 times / 43% more likely

For a good event
- Greater than 1 means more likely for good event
- Less than 1 means less likely for good event

Question 19

Understanding Confidence Intervals
- 1.43 [0.51,4.05]

What does 0.51 mean

Answer 19

Lower limit
- Cure rate are up to 50% / 0.50 times lower with duct tape

Question 20

Understanding Confidence Intervals
- 1.43 [0.51,4.05]

What does 4.05 mean

Answer 20

Upper limit
- Cure rate are up to 300% / 4 times higher with duct tape

Question 21

Understanding Confidence Intervals
- Sufficiently precise

Answer 21

If 95% CI crosses a decision threshold then the results are not sufficiently precise

If 95% CI does not cross a decision threshold then the results are sufficiently precise

Question 22

Relevance

Answer 22

1. Does the info focus on outcomes patients care about
2. Is the intervention feasible and is the problem it addresses common
3. Would the information cause a change in practice

If yes to all 3 it is patient oriented evidence

Question 23

Validity

Answer 23

Technical rigor of the work (Is it accurate?)

Question 24

Work

Answer 24

Time, money, and effort to answer a question

Question 25

Usefulness of Medical Information

Answer 25

(Relevance * Validity) / Work

Question 26

Different Types of Bias

Answer 26

1. Detection Bias
2. Observer Bias
3. Publication Bias
4. Recall Bias
5. Selective Outcome Reporting Bias
6. Social Desirability Bias

Question 27

Sources of Bias
- Differences at the start of a study

Answer 27

Between group differences in prognosis

Question 28

Reducing Bias
- Differences at the start of a study

Answer 28

Randomization, Allocation concelment

Question 29

Source of Bias
- Differences that Occur as the study proceeds

Answer 29

Placebo Effect
Co-intervention
Bias in assessment of outcomes

Question 30

Reducing Bias
- Differences that Occur as the study proceeds (Placebo)

Answer 30

Blinding of Patients

Question 31

Reducing Bias
- Differences that Occur as the study proceeds (Co-intervention)

Answer 31

Blinding of caregivers

Question 32

Reducing Bias
- Differences that Occur as the study proceeds (Assessment)

Answer 32

Blinding of assessors of outcomes

Question 33

Source of Bias
- Differences at the Completion of the study

Answer 33

• Loss to follow-up
• Stopping early because of large effect
• Omitting patients who did not receive assigned treatment

Question 34

Reducing Bias
- Differences at the Completion of the study (Follow Up)

Answer 34

Ensure complete follow up

Question 35

Reducing Bias
- Differences at the Completion of the study (Stopping early)

Answer 35

Completing study as initially planned

Question 36

Reducing Bias
- Differences at the Completion of the study (Omitting patients)

Answer 36

Adhering to the intention to treat principle
- Analyze patients in the arm where they were originally randomized