Level of evidence
Category	Quality of level	Source	CSCO expert consensus
1A	High	Based on data from well‐structured and rigorously controlled meta‐analysis, and/or large‐scale, randomized controlled clinical trials	Uniform consensus achieved (support level: ≥80%)
1B	High	Based on data from well‐structured and rigorously controlled meta‐analysis, and/or large‐scale, randomized controlled clinical trials	Consensus achieved with minimum disagreement (support level: 60%‐80%)
2A	Relatively low	Based on data from meta‐analysis, small‐scale randomized controlled trials, well‐designed large‐scale retrospective studies, and/or case‐control studies	Uniform consensus achieved (support level: ≥80%)
2B	Relatively low	Based on data from meta‐analysis, small‐scale, randomized controlled trials, well‐designed large‐scale retrospective studies, and/or case‐control studies	Consensus achieved with minimum disagreement (support level: 60%‐80%)
3	Low	Based on data from single‐arm clinical studies, case reports, and/or expert opinions	No consensus reached and had major disagreement (support level: <60%)