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Neurology Week 5 2018/19 > 5: Critical appraisal > Flashcards

Flashcards in 5: Critical appraisal Deck (22)
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1

What is critical appraisal?

Evaluating a piece of research to determine if it's valid i.e can you trust its methods and its conclusions

2

What is

a) internal

b) external

validity in relation to research?

a) Are the method and results sound

b) Can you apply the results of the study to real life

3

What does efficacy mean?

Ability to produce desired result

4

What does effectiveness mean?

Measure of an intervention's benefit in real life

5

What is the impact factor of a journal?

How well respected it is, doesn't automatically mean the study will be good but good journals tend not to accept crap studies

6

How does a cross-sectional study work?

Take a large group and use a questionnaire to split them into subgroups

Gives you an idea of risk factors and disease prevalence at a snapshot in time

7

Cross-sectional studies can only measure (incidence / prevalence).

prevalence

8

What is a case-control study?

Comparing two groups (disease vs control) and their exposure to a risk factor

i.e looking back to see if a certain isolated risk factor has increased the likelihood of x

9

Case-control and cross-sectional studies are (retrospective / prospective).

retrospective

10

What is a cohort study?

Take a group of individuals

filter into subgroups for risk factors they're exposed to (or not)

follow subgroups over time and see how risk factors affected disease incidence

11

cohort study is (prospective / retrospective).

prospective

12

In cohort studies, there is a risk that participants are ___ to follow-up.

lost

13

What is the gold-standard study design for clinical trials?

Randomised control trial

14

What does intention to treat mean in relation to randomised control trials?

Patient results are attributed to the group they were in initially, even if they change / stop the new intervention

15

What is per protocol analysis in relation to randomised control trials?

Only those who finish treatment on the new intervention are analysed in the 'new intervention' results

16

Whether you use intention to treat or per protocol analysis will change the study's ___.

results

17

Which analysis method for RCTs (intention to treat or per protocol) is more accurate?

Intention to treat

Per protocol tends to make the new intervention look better, as you're cutting out the patients who stopped or changed treatment

18

What is the difference between statistical significance and clinical significance?

Statistical significance - difference in results is unlikely to be due to margin of error; it's unlikely that the null hypothesis is true

Clinical significance - changing management will make a difference to patient outcomes, benefits outweigh risks e.g side effects

A study proving a drug lowers BP by 2 mmHg may be statistically significant but NOT clinically significant

19

How do you calculate absolute risk?

Number of events observed / No. of participants in total

20

How do you calculate relative risk?

Absolute risk intervention / Absolute risk control

21

What is a confounding variable?

Variable which isn't not being taken into account which may alter the results of a trial

22

What is publication bias?

Trials which have valuable (but 'boring') results e.g proving the null hypothesis are less likely to be published in journals