All EBM Guidelines Evidence Summaries contain an evaluation of the quality of the evidence, determined according to the principles of the GRADE system. The evidence statements have PICO format (Patient, Intervention, Comparison, Outcome), and they use standard wording for each four levels of evidence. If the quality of evidence has been downgraded or upgraded, a comment after the evidence statement lists the reasons for downgrading or upgrading using standard phrases.
A recommendation using standard wording is included in those Evidence Summaries where a recommendation can be given on the basis of the evidence and consensus within the EBM Guidelines Editorial Team. A comment using standard expressions states the reasons for giving a weak recommendation on the basis of high quality evidence or a strong recommendation on the basis of low quality evidence.
Disclaimer: The standard wordings in the following tables have been formulated by the EBM Guidelines Editorial Team on the basis of the GRADE Group publications, and they should be considered as a work under development. They will be revised after feedback from users and stakeholders.
An example of an Evidence Summary with standard wording Psa for Screening of Prostate Cancer
| Level of evidence | Definition | Wording * |
|---|---|---|
| A (high) | We are very confident that the true effect lies close to that of the estimate of the effect. | …is effective / has some effect / is not effective / is harmful… |
| B (moderate) | We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. | appears to be effective / appears to have some effect / appears not to be effective / appears to be harmful… |
| C (low) | Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect. | may be effective / may have limited effect / may not be effective / may be harmful… |
| D (very low) | We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect. | might possibly/might possibly not ….be effective/have limited effect/be harmful… but the evidence is insufficient**There is insufficient evidence on the effect... *** |
* A suitable verb can be used instead of the word “effective”, e.g. “...appears to improve survival”; “...may not prevent exacerbations”. ** “Might possibly be effective/have limited effect/be harmful” can be used when the point estimate suggests clinically meaningful/almost clinically meaningful beneficial or harmful effect. *** This expression is used if no point estimate of the effect is available. | ||||||||||||||||||||||||||||||||||||||||||||
Rating down/up in RCTs
Determinants of strength of recommendations
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* This expression can be used if alternative interventions exist and they might be as good or better options, but comparative studies are not available. **This expression can be used if a strong recommendation is given in spite of low quality evidence. The resource consumption of the intervension should usually be low in this case. *** No comment is needed if low quality of the evidence is the only reason for a weak recommendation. | ||||||||||||||||||||||||||||||||||||||||||||
| References | ||||||||||||||||||||||||||||||||||||||||||||
Guyatt GH, Oxman AD, Schünemann HJ et al. GRADE guidelines: a new series of articles in the Journal of Clinical Epidemiology. J Clin Epidemiol 2011;64(4):380-2. [PubMed]
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