Asthma Management Handbook

Methods used for developing evidence-based recommendations

For each of the systematic reviews, the research assistant and secretariat prepared evidence reports for the working group, with advice from the methodologist.

The working group met in person to interpret the evidence and develop evidence-based recommendations. For each recommendation, the working group identified the relevant body of evidence (e.g. the full set of studies in the evidence report, or a selection where a recommendation was based on a sub-population or a specific intervention).

The working group graded each recommendation using the NHMRC system for grading a recommendation.1

Table. National Health and Medical Research Council (NHMRC) body of evidence matrix

Component A
Excellent
B
Good
C
Satisfactory
D
Poor
Evidence base One or more level I studies with a low risk of bias or several level II studies with a low risk of bias


 
One or two level II studies with a low risk of bias or a SR/several level III studies with a low risk of bias
 
One or two level III studies with a low risk of bias, or level I or II studies with a moderate risk of bias Level IVstudies, or level I to III studies/SRs with a high risk of bias
Consistency All studies consistent


 
Most studies consistent and inconsistency may be explained Some inconsistency reflecting genuine uncertainty around clinical question Evidence is inconsistent
Clinical impact Very large Substantial Moderate Slight or restricted
Generalisability Population/s studied in body of evidence are the same as the target population for the guideline Population/s studied in the body of evidence are similar to the target population for the guideline Population/s studied in body of evidence differ to target population for guideline but it is clinically sensible to apply this evidence to target population Population/s studied in body of evidence differ to target population and hard to judge whether it is sensible to generalise to target population
Applicability Directly applicable to Australian healthcare contex Applicable to Australian healthcare context with few caveats Probably applicable to Australian healthcare context with some caveats Not applicable to Australian healthcare context

SR, systematic review; several, more than two studies.

Source

National Health and Medical Research Council (NHMRC), NHMRC additional levels of evidence and grades for recommendations for developers of guidelines. NHMRC, Canberra, 2009.

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The methodologist and research assistant gave specific advice on how to score the ‘consistency’ and ‘evidence base' domains. Advice was also given to help score the remaining domains.

The working groups finalised the recommendation grades over a series of face-to-face meetings and teleconferences, supplemented by online surveys to streamline the process.

References

  1. National Health and Medical Research Council (NHMRC). NHMRC additional levels of evidence and grades for recommendations for developers of guidelines. NHMRC, Canberra, 2009. Available from: http://www.nhmrc.gov.au/guidelines/resources-guideline-developers