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Table 1A. THS/TSOC classes of recommendations (updated March 2019).

Classes of recommendations Definition Suggested phrases
Class I (Benefit >>> Risk) Evidence and/or general agreement that a given treatment of procedure is beneficial, useful, and effective • Is recommended
• Is indicated
• Should be performed
Class II Conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of the given treatment or procedure
 Class IIa (Benefit >/>> Risk) Weight of evidence/opinion is in favor of usefulness/efficacy • Is probably recommended
• Should be considered
• Can be performed
 Class IIb (Benefit ≥ Risk) Usefulness/efficacy is less well established by evidence/opinion • May/might be considered
• May/might be reasonable
• May/might be performed
Class III (Benefit ≤ Risk) Evidence or general agreement that the given treatment or procedure is not useful/effective, and in some cases may be harmful • Is not recommended
• Is not indicated
• Should not be performed

THS, Taiwan Hypertension Society; TSOC, Taiwan Society of Cardiology.