Week 2 - Principles of Evidence-Based Practice II

Question 1

When appraising evidence, what specific things should you consider? (There are 3)

Answer 1

Validity
Clinical Importance
Applicability

Question 2

Name the critical appraisal skills program (CASP) tools

Answer 2

systematic reviews
RCTs
Case-control studies
Cohort studies

Question 3

What does RAMMBO stand for?

Answer 3

Recruitment (representative pop?)
Allocation (randomised?)
Maintenance (everyone treated equally?)
Measurement (was everyone Blinded to treatment? Were measurements Objective and standardised?)

Question 4

In the example study given during the lecture (deep vein thrombosis) how were the control and experiment groups different?

Answer 4

The experimental group had more women, hence, higher rates of hormone replacement therapy (HRT) in the experimental group

Question 5

Was the study (deep vein thrombosis) blinded?

Answer 5

The outcome assessors were not aware of which study groups the subjects were in, however, the subjects knew (could solve this by using a placebo stocking).

Question 6

what is a consort diagram/ statement?

Answer 6

The CONSORT Statement is an evidence-based, minimum set of recommendations for reporting RCTs.

Transparency- how participants progressed through the study: allocation, exclusions, randomisation, analysis etc.

Question 7

What calculations can you make that help to evaluate clinical significance? And what do they explain?

Answer 7

Event Rate: how often outcome is observed in control and treatment conditions
Absolute and Relative Risk: to allow comparison between control and treatment conditions
Number Needed to Treat: number needed to treat to prevent a bad outcome

Question 8

Why aren’t all effect sizes created equal?

Answer 8

Effect sizes can be used to represent the strength of a relationship between two variables (r), or it can be used to describe the mean difference between two groups (Cohen’s d)

the meaning of an effect size depends on context: a ‘small’ effect size might be considered large depending on the area of study

Question 9

List the two kinds of event rates

Answer 9

CER: control event rate
EER: experimental event rate

Question 10

Explain how to work out the absolute risk reduction

Answer 10

difference in the event rates in the two groups (the size of the treatment effect)

If 20% of patients die with no treatment (A), and 15% die with treatment (B), there is a 5% absolute risk reduction with treatment B:
CER-EER = 0.20 - 0.15 = .05
For every 100 patients enrolled in the treatment group, about 5 bad outcomes would be averted.

Question 11

Explain how to work out the number needed to treat

Answer 11

Number needed to treat = 1/ absolute risk reduction
NNT = 1/ARR

(in the example with 20% of patients dying with no treatment (A), and 15% dying with treatment (B))

ARR = CER - EER = .05
NNT = 1/ .05 =
So the number you need to treat one person to benefit is 20

Question 12

how do you work out Relative Risk Reduction?

Answer 12

RRR is the difference in event rates between two groups, expressed as a proportion of the event rate in the untreated group

RRR = (CER - EER)/ CER = (0.20 - 0.15)/0.20 = 0.25

This means that the disease/ disorder was reduced by 25% in the treatment group compared with the control

Question 13

Explain the Odds Ratio (OR)

Answer 13

measure of association between an exposure and an outcome.

OR = exposed to smoking and have lung cancer/ exposed to smoking and don’t have lung cancer

https://www.youtube.com/watch?v=ITi0SxmQTO8

Question 14

What do you have to consider when applying the evidence to your client? (4 things).

Answer 14

1. Individual baseline risk
2. Judge whether evidence can be extrapolated to your client
3. Understanding factors that may increase benefits or harm their experience
4. Qualitative evidence