NLA GUIDELINES Bundle (free trial)

6 Quality b Type of Evidence High • Well-designed, well-executed RCTs that adequately represent populations to which the results are applied and directly assess effects on health outcomes • Well-conducted meta-analyses of such studies • Highly certain about the estimate of effect; further research is unlikely to change our confidence in the estimate of effect Moderate • RCTs with minor limitations affecting confidence in, or applicability of, the results • Well-designed, well-executed nonrandomized controlled studies and well-designed, well-executed observational studies • Well-conducted meta-analyses of such studies • Moderately certain about the estimate of effect. Further research may have an impact on our confidence in the estimate of effect and may change the estimate Low • RCTs with major limitations • Nonrandomized controlled studies and observational studies with major limitations affecting confidence in, or applicability of, the results • Uncontrolled clinical observations without an appropriate comparison group (eg, case series, case reports) • Physiological studies in humans • Meta-analyses of such studies • Low certainty about the estimate of effect. Further research is likely to have an impact on our confidence in the estimate of effect and is likely to change the estimate. a is was the system used in the new American Heart Association/American College of Cardiology cholesterol guidelines that were published in the 2014 Evidence-Based Guideline for the Management of High Blood Pressure in Adults Report from the Panel members appointed to the Eighth Joint National Committee. Permission to reuse table granted by the American Medical Association. b e evidence quality rating system used in this guideline was developed by the National Heart, Lung and Blood Institutes (NHLBI's) Evidence-Based Methodology Lead (with Input from NHLBI staff, external methodology team, and guideline panels and work groups) for use by all the NHLBI cardiovascular disease guideline panels and work groups during this project. As a result, it includes the evidence quality rating for many types of studies, including studies that were not used in this guideline. Additional details regarding the evidence quality rating system are available in the online Supplement. Grade c Strength of Recommendation A Strong recommendation ere is high certainty based on the evidence that the net benefit d is substantial. D Recommend against ere is at least moderate certainty based on the evidence that it has no net benefit or that the risks/harms outweigh benefits. B Moderate recommendation ere is moderate certainty based on the evidence that the net benefit is moderate to substantial, or there is high certainty that the net benefit is moderate. E Expert opinion ere is insufficient evidence or evidence is unclear or conflicting, but this is what the expert panel recommends. C Weak recommendation ere is at least moderate certainty based on the evidence that there is a small net benefit. N No recommendation for or against c e system was adapted as a hybrid of the National Heart Lung and Blood Institute's (NHLBI) rating system (NHLBI cardiovascular-based methodolog y) used in the new American Heart Association/American College of Cardiolog y cholesterol guidelines and adapted from the original GRADE system of evidence rating. d Net benefit is defined as benefits minus risks/harms of the service/intervention. Evidence Grading a

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