General Questions

Question 1

Link these question types with the relevant study types
1 - aetiology
2 - how to diagnose
3 - effectiveness
4 - patient experience
5 - demographic/incidence

A - qualitative studies
B - RCTs
C - case control/cohort
D - descriptive studies
E - diagnostic test accuracy studies

Answer 1

1 - C
2 - E
3 - B
4 - A
5 - D

Question 2

What are the 4 A’s? (And what do they mean?)

Answer 2

A - assess (PICOS)
A - access (NICE, evidence summaries, SRs, primary studies, expert opinion)
A - appraise (CASP)
A - apply/act (skills, cost, accessibility, plausibility)

Question 3

When might the best evidence still not provide certainty about management to a patient?

Answer 3

1. Many studies are based on population data; what my be applicable to the population may not be for an individual pt
2. Multiple options available (patient’s wants & needs come first wrt potential side effects)
3. ‘Best evidence’ may still not be applicable to pt (excluded groups)
4. May still not be enough evidence to use certain treatments

Question 4

What is the GRADE tool?

Answer 4

? DM lecture

Question 5

Generalisability/external validity

Answer 5

PICO relevant to your local context?

P - patients similar in demographic/characteristics/stage of disease
I - feasibility/cost of intervention, alternatives available & effect clinically significant?
C - is the comparator the baseline treatment in my healthcare setting?
O - were all important outcomes considered?
(Benefits, harms, PROs & PROMs)

• implications for practice (would you recommend + justify why)

Question 6

When asked to explore a study further, what questions could you ask?

Answer 6

DTA - cost of test, patient experience of using test, HCP experience

Question 7

Explaining a box and whisker plot

Answer 7

Box = summary/point estimate for that single study - may be mean difference
Whisker = CI (precision)

Explaining where it lies in a forest plot:
- size of effect (point estimate, where lies on x-axis)
- direction of effect (position relative to line of no effect, positive/negative & significance of this)
- weight of study (size of box, given as percentage in next column)
- precision (95% CI, describe what effect the intervention could confer)
- significance of effect (whether the CI overlaps with line of no effect)

Question 8

Meta-analysis/forest plot - explain the diamond at the bottom of each sub-plot

Answer 8

Vertical axis - point pooled estimate of studies above
Horizontal axis - CI pooled estimate

(Comment on size, direction, precision & significance of pooled estimate)

Question 9

What is I²?

Answer 9

A quantitative measure of heterogeneity.

Heterogeneity - a measure of variation in effect sizes across included studies in a meta-analysis that is not accountable to chance

Question 10

What factors may increase heterogeneity between studies?

Answer 10

Clinical:
Population
- types/stage of disease, severity, spread
- stage of treatment/previous intervention
- age of participants (also ethnicity, race, sex etc)
- type of treatment & where available
- motivation of people taking part (could also be affected by demographic)
Intervention
- type of intervention (ie. - definitions for ‘moderate exercise’)
- dose (duration, intensity, who delivers/self-administered?)
- support available & degree of follow up
- ease of access/some degree of healthy reproducer/ptpt effect?
Outcome
- variation in outcome measure/tools used - detection bias

Methodological:
Study design
- variation in quality of studies
- variation in study protocol (ie - levels of confounding, bias and recruitment strategies)

Question 11

What is the null hypothesis (H0)

Answer 11

No statistically significant difference between the two groups/arms

Question 12

What is evidence based practice?

Answer 12

The combination of:
- the best available evidence
- the doctor’s own clinical expertise
- patient’s ICE & preferences

Question 13

When conducting a literature search, what must you check for at each step?

Answer 13

• quality
• relevance
• currency

Question 14

What are evidence summaries?

Answer 14

Summarises existing evidence using SRs & identifies gaps in the evidence

Question 15

How do clinical guidelines differ from evidence summaries?

Answer 15

• conduct de novo SRs
• comprehensive review of 1ry & 2ry sources & economic analysis
• addresses entire disease pathway, searches driven by need for info not restricted by quality of evidence
• use GRADE to evaluate confidence in evidence
• engage stakeholders
• develop recommendations for clinical practice

Question 16

What does the GRADE tool do?

Answer 16

Summarises strength of evidence at level of clinical question/outcome of interest, provides a systematic approach for developing recommendations

Question 17

What are the 5 domains of the GRADE tool?

Answer 17

Risk of Bias (evidence hierarchy & critical appraisal)
Imprecision (width CI, worst possible est effect?)
Inconsistency (CI overlap, heterogeneity)
Indirectness (applicability to pop/setting (PICO)
Publication bias (‘missing studies’, pot effect on est effect)
- English language, effect size

Question 18

What factors are considered when making strong recommendations?

Answer 18

• strength/certainty of evidence (GRADE)
• size of effect (relative to adverse eff)
• cost/resource
• pt preference

Question 19

What are the 6 domains from the AGREE II tool?

Answer 19

1. Scope & purpose
2. Stakeholder involvement (guideline development group, all relevant professional groups, views & preferences target pop)
3. Rigour of development (clear descriptions, systematic methods, strengths & limitations)
4. Clarity of presentation (specific, different options)
5. Applicability ( facilitators & barriers, resource implications, advice, monitoring/auditing criteria)
6. Editorial independence (conflicting interests)

Question 20

What is the difference between internal & external validity?

Answer 20

Internal validity - degree to which effect observed is attributable to evidence & not other internal factors (bias & confounding)

External validity - affected by internal validity, ability to generalise to local population

Question 21

In an open study, how do you measure risk?

Answer 21

Person years

Measure of length of time individual has been in study (when ptpts in study for different times)

Question 22

What is the difference between study population & study sample?

Answer 22

Pop - all from target pop who would be eligible for study
Sample - those who actually participate