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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
Q

What is critical appraisal?

A

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

2
Q

What is

a) internal
b) external

validity in relation to research?

A

a) Are the method and results sound
b) Can you apply the results of the study to real life

3
Q

What does efficacy mean?

A

Ability to produce desired result

4
Q

What does effectiveness mean?

A

Measure of an intervention’s benefit in real life

5
Q

What is the impact factor of a journal?

A

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

6
Q

How does a cross-sectional study work?

A

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
Q

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

A

prevalence

8
Q

What is a case-control study?

A

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
Q

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

A

retrospective

10
Q

What is a cohort study?

A

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
Q

A cohort study is (prospective / retrospective).

A

prospective

12
Q

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

A

lost

13
Q

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

A

Randomised control trial

14
Q

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

A

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

15
Q

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

A

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

16
Q

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

A

results

17
Q

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

A

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
Q

What is the difference between statistical significance and clinical significance?

A

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
Q

How do you calculate absolute risk?

A

Number of events observed / No. of participants in total

20
Q

How do you calculate relative risk?

A

Absolute risk intervention / Absolute risk control

21
Q

What is a confounding variable?

A

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

22
Q

What is publication bias?

A

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