Table 2. Analysis of the quality of evidence (GRADE) in relation to the overall rate of occurrence of the assessed outcomes.

Certainty assessment								Patients (n)		Certainty of evidence
Outcome follow-up	Studies (n)	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Others considerations	OAGB	Control
BMI at 6-month	3	RCT	VS	Serious (I2>50)	NS	VS	None	78	80	⊕⭘⭕⭕ Very low
BMI at 1-year	4	RCT	VS	NS	NS	Serious	None	117	129	⊕⭘⭕⭕ Very low
BMI at 5-year	2	RCT	VS	NS	NS	Serious	None	82	90	⊕⭘⭕⭕ Very low
%EWL at 1-year	4	RCT	VS	Serious (I2>50)	NS	NS	None	129	139	⊕⭘⭕⭕ Very low
%EWL at 5-year	2	RCT	VS	Serious (I2>50)	NS	VS	None	82	90	⊕⭘⭕⭕ Very low

BMI: body mass index; OAGB: one anastomosis gastric bypass; RCT: randomized controlled trial; VS: very serious; NS: not serious; EWL: excess weight loss.