TableĀ 1

American College of Chest Physicians classification scheme for grading evidence and recommendations used in this statement2

GradeDescriptionBenefits versus risks and burdensMethodological quality of supporting evidence
1AStrong recommendation, high-quality evidenceBenefits clearly outweigh risks and burdens or vice versaRCTs without important limitations or overwhelming evidence from observational studies
1BStrong recommendation, moderate-quality evidenceBenefits clearly outweigh risks and burdens or vice versaRCTs with important limitations or exceptionally strong evidence from observational studies
1CStrong recommendation, low-quality or very low-quality evidenceBenefits clearly outweigh risks and burdens or vice versaObservational studies or case series
2AWeak recommendation, high-quality evidenceBenefits closely balanced with risks and burdensRCTs without important limitations or overwhelming evidence from observational studies
2BWeak recommendation, moderate-quality evidenceBenefits closely balanced with risks and burdensRCTs with important limitations or exceptionally strong evidence from observational studies
2CWeak recommendation, low-quality or very low-quality evidenceUncertainty in the estimates of benefits, risks and burden; benefits, risk and burden may be closely balancedObservational studies or case series
  • RCT, randomised controlled trial.