| Appendix 2 |
|
| Definitions
of strength of evidence grades |
|
| US guideline17 | |
| a) | Multiple well-designed randomized clinical trials, directly relevant to the recommendation, yielded a consistent pattern of findings. |
| b) | Some evidence from randomized clinical trials supported the recommendation, but the scientific support was not optimal. For instance, either few randomized trials existed, the trials that did exist were somewhat inconsistent, or the trials were not directly relevant to the recommendation. |
| c) | Reserved for important clinical situations where the panel achieved consensus on the recommendation in the absence of relevant randomized controlled trials. |
| UK guideline18 | |
| a) | Many well designed randomized controlled trials directly relevant to the recommendation, yielding a consistent pattern of findings. |
| b) | Some evidence from randomized controlled trials, but not optimal. More interpretation of the evidence was needed. |
| c) | No randomized controlled trials but the issue is important enough to merit a recommendation which is based on published evidence and expert opinion of the authors and reviewers. |
| New Zealand guideline19 / Canada guideline20 | |
| I) | Evidence obtained from at least one properly randomized controlled trial. |
| II-a) | Evidence obtained from well-designed controlled trials without randomization. |
| II-b) | Evidence obtained from well-designed cohort or case control analytic studies, preferably from more than one centre or research group. |
| II-c) | Evidence obtained from multiple time series with or without intervention.III) Opinions of repeated authorities, based on clinical experience. |