Systematic Reviews and Meta Analysis

Question 1

Define systematic reviews

Answer 1

A review of clearly formulated question that uses systematic and explicit methods

• Identifies, selects and critically appraises relevant research
• Collects and analyses data from studies that are included in the review
• Involves collating all of the experimental evidence i.e. “a study of studies”

Question 2

What is the rationale for systematic reviews

Answer 2

Often individual studies may not be large enough to produce answers on their own

There may be conflicting results across studies resulting in different conclusions

Question 3

5 types of evidence

Answer 3

1. Clinical opinion - based on experience/expertise
2. Case reports - a finding from a single patient
3. Case series - a number of cases
4. Case-control studies - a retrospective study that compares subjects who have a condition (cases) with patients who do not (controls)
5. Randomised controlled studies (RCTs) - prospective investigations of effects where groups are assigned before treatment begins // GOLD STANDARD

Question 4

Evidence Based Medicine Pyramid

Answer 4

Question 5

What is a meta-analysis

Answer 5

An optional part of a systematic review

Necessary as most treatments are only moderately effective

Question 6

How do we demonstrate/refute moderate treatment effects

Answer 6

Avoid:

1. Moderate random errors (fluctuations from the “truth” due to the play of chance)
2. Moderate biases (i.e. systematic differences from the “truth” due to e.g. study design)

Question 7

When do you conduct a meta-analysis

Answer 7

• When more than 1 study has estimated an effect
• If the patients, interventions and outcomes are sufficiently similar to produce a clinically useful and meaningful result
• When the data is available
• The effect size with 95% CIs is constructed for each study and these are lined up as a forest plot

Question 8

Explain the forest plot and the Cochrane logo

Answer 8

• The circle formed by two ‘C’ shapes represents our global collaboration
• The lines within illustrate the summary results from an iconic systematic review. Each horizontal line represents the results of one study
• The diamond represents the combined result, our best estimate of whether the treatment is effective or harmful

Question 9

Name the 3 main glucocorticoids

Answer 9

Dexamethasone

Hydrocortisone

Methylprednisolone

Question 10

What type of agents are glucocorticoids

Use in Covid-19 patients

Answer 10

Strong anti-inflammatory agents

Question 11

What are the concerns with SSRI (selective serotonin reuptake inhibitors) anti-depressants

Answer 11

• No better than placebos
• No dose-response relationship
• The effect of SSRIs is so small as to not be clinically meaningful
• Only of benefit in severe depression
• Beneficial effects are due to side effects augmenting the placebo effect

Question 12

SSRI antidepressant systematic review

Answer 12

All antidepressants had a greater efficacy than placebo