Appendix 3: Grading of Evidence
Levels of evidence for studies of intervention
Levels of evidence for validity of candidate risk factors
Of note, FRAX risk factors are all grade A or B according to evidence for reversibility of risk 63.
Grading of recommendations
Recommendations follow the Grading of Recommendations Assessment, Development, and Evaluation GRADE binary classification of recommendations as either strong or conditional (also known as discretionary or qualified recommendations) 311. Recommendations have been made after assessment of 312:
- The balance between desirable and undesirable effects -The larger the difference between the desirable and undesirable effects, the more likely a strong recommendation is warranted.
- The quality of evidence - The higher the quality of evidence, the more likely a strong recommendation is warranted.
- Values and preferences - The more variability/ uncertainty in values and preferences the more likely a conditional recommendation is warranted.
- Costs (resource allocation) - The higher the costs of an intervention (i.e., the more resources consumed) the more likely a conditional recommendation is warranted.
For example, a strong recommendation applies where the clinician considers that most people ought to receive the intervention, or where adherence to the recommendation could be used as a performance or quality indicator and that deviation from this recommendation would prompt documentation of a clinician’s rationale. NICE suggests using ‘offer’ (or similar action wording such as ‘measure’, ‘advise’, ‘commission’ or ‘refer’) when describing a strong recommendation313.
A conditional recommendation applies where the clinician examines the evidence and prepares to discuss this with the patient together with the patient’s values and preferences, or where documentation of the discussion of the pros and cons of an intervention is the indicator of quality, rather than the course of action itself. NICE suggests using wording such as ‘consider’ when describing conditional recommendations.
Where insufficient evidence is available or the evidence available is equivocal, recommendations are not made.