22-11-21 - Information Quality not Quantity

Question 1

Learning outcomes

Answer 1

• Explain the importance of using up to date evidence for addressing clinical questions
• List potential sources of bias in medical research
• Describe the strategy for conducting a systematic review
• Explain the value of a meta-analysis
• Explain the importance of a confidence interval
• Interpret a Forest Plot

Question 2

What are the 3 principles of evidence-based medicine?

Answer 2

• Principles of evidence-based medicine:

1) High quality healthcare rests on the objective and clinically relevant information
2) There is a hierarchy of evidence where some types are stronger than others
3) Scientific data alone is not sufficient basis for making clinical decisions

Question 3

What is the number needed to treat (NNT)?

What is the ideal NNT?

Answer 3

• The number needed to treat is the number of patients who need to be treated in order for one person to benefit
• Ideally the NNT is 1 ie everyone wo is treated benefits
• The larger the NNT, the less benefit

Question 4

What are 3 simple rules when choosing a starting point?

Answer 4

• Rules when choosing a starting point:

1) Questions about treatment alternatives or therapeutic effects involving common illnesses can be found in the systematic reviews/meta-analyses
2) General recommendations relating to common illnesses can be found in the clinical practise guidelines
3) Always begin a search with high quality secondary information sources (the science has already been vetted by experts

Question 5

What does a systematic review attempt to do?

What do researchers who conduct systematic reviews do?

Answer 5

• A systematic review attempts to identify, appraise and synthesis and the empirical evidence that meets pre-specified eligibility criteria to answer a given research question
• Researchers conducting systematic reviews use explicitly methods aiming at minimizing bias, in order to produce more reliable findings that can be used to inform decision making

Question 6

What is a meta-analyses?

What is the aim of this?

Answer 6

• A meta-analysis is when results of the individual studies are combined to produce an overall statistic
• Data is collected from more than one clinical trial and are combined to generate an average result
• This aims to provide a more precise estimate of the effects of an intervention and to reduce uncertainty

Question 7

What does a point estimate indicate?

What does the confidence interval describe?

How does a wide and narrow confidence interval affect our confidence in results?

Answer 7

• The point estimate (usually the mean) indicates the magnitude of the effect if the experimental intervention compared to the control intervention
• The confidence interval describes the uncertainty of this estimate
• It describes the range of values within which we can be reasonable sure that the true effect actually lies in

Question 8

How do we answer a clinical question?

Answer 8

• To answer a clinical question, we start with systematic reviews or meta-analyses (Cochrane database or another source of high-quality systematic reviews
• The we use NICE and SIGN guidelines
• And only then use primary research literature