Table 2.

Summary of findings: association of prior bariatric surgery with mortality and hospitalization in patients with COVID-19

Outcomes	Anticipated absolute effects* (95% CI)		Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)
	Risk without bariatric surgery history	Risk with previous bariatric surgery
Mortality	133 per 1000	33 per 1000 (28 to 38)	OR 0.22 (0.19 to 0.26)	9022 (3 observational studies)	⨁⨁⨁◯ Moderate
Hospital Admission	412 per 1000	164 per 1000 (78 to 313)	OR 0.28 (0.12 to 0.65)	736 (2 observational studies)	⨁⨁⨁◯ Moderate

GRADE Working Group grades of evidence [19]:

High certainty: We are very confident that the true effect lies close to that of the estimate of the effect

Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different

Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect

Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect

CI, confidence interval; OR, odds ratio

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI)