Summary of findings 1. Obesity Class I compared to Normal Weight or Non‐Obese for Adults with COVID‐19.

Obesity class I (30 kg/m2 ≤ BMI < 35 kg/m2) compared to normal BMI or patients with a BMI < 30 kg/m2 for adults with COVID‐19
Patient or population: Adults with COVID‐19  Settings: Community and in‐hospital
Outcomes Time frame of absolute effects	Absolute effects from study(ies)* (95% CI)			Relative effect 95% CI	No of Participants (studies)	Quality of the evidence (GRADE)	Plain language summary
	Normal BMI or Non‐Obese	Obesity Class I	Difference with Obesity Class I
Mortality (in‐hospital)	180 per 1000	186 per 1000	6 more per 1000 (9 fewer to 23 more)	Odds Ratio: 1.04(CI 95% 0.94 to 1.16)1	335,209 (15)	⊕ ⊕ ⊕ ⊕ HIGH2	Obesity class I has little or no difference on mortality.
Mechanical ventilation (in‐hospital)	198 per 1000	254 per 1000	56 more per 1000 (31 more to 84 more)	Odds Ratio: 1.38(CI 95% 1.2 to 1.59)3	187,895 (10)	⊕ ⊕ ⊕ ⊖ MODERATE4	Obesity class I probably increases the risk of mechanical ventilation.
ICU admission (in‐hospital)	208 per 1000	263 per 1000	55 more per 1000 (10 more to 107 more)	Odds Ratio: 1.36(CI 95% 1.06 to 1.75)5	162,741 (7)	⊕ ⊕ ⊕ ⊖ MODERATE6	Obesity class I probably increases the risk of ICU admission.
Hospitalisation (30‐days, community)	146 per 1000	141 per  1000	5 fewer per 1000 (23 fewer to 17 more)	Odds Ratio: 0.96(CI 95% 0.82 to 1.14)7	515,155 (5)	⊕ ⊕ ⊕ ⊖ MODERATE8	Obesity class I probably has little or no difference on the risk of hospitalisation.
Severe COVID‐19 (in‐hospital)	158 per 1000	217 per  1000	59 more per 1000 (21 more to 102 more)	Odds Ratio: 1.48(CI 95% 1.16 to 1.87)9	1040 (3)	⊕ ⊕ ⊖ ⊖ LOW10	Obesity class I may increase the risk of severe Covid‐19.
Pneumonia	‐	‐	‐	‐	‐	‐	No studies were found that looked at the impact of obesity class I on pneumonia.
*The basis for the control group absolute risks from the study(ies) is mean risk across study(ies) unless otherwise stated in comments. The intervention absolute risk and difference is based on the risk in the comparison group and the relative effect of the intervention (and its 95% CI).
GRADE Working User Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate.

1.Systematic review. Baseline/comparator control arm of reference used for intervention. 

2. No reasons to rate down.

3. Systematic review. Baseline/comparator control arm of reference used for intervention. 

4. Imprecision: serious. The lower bound 95% CI crossed our absolute risk difference of 50 per 1000 patients followed.

5. Systematic review. Baseline/comparator control arm of reference used for intervention.

6. Inconsistency: serious. Lack of overlap in point estimates and 95% CI across studies. Our subgroup analyses failed to explain the observed heterogeneity. Low credibility (based on ICEMAN) for one statistically significant subgroup analysis based on the reference group. 

7. Systematic review. Baseline/comparator control arm of reference used for intervention.

8. Inconsistency: serious. A significant subgroup effect was observed based on the adjustment criteria. The credibility of this subgroup effect, however, was low (based on ICEMAN). 

9. Systematic review. Baseline/comparator control arm of reference used for intervention. 

10. Risk of Bias: serious. 2 of 3 studies were at an overall high risk of bias. Imprecision: serious. The lower bound 95% CI crossed our prespecified absolute risk difference threshold of 50 per 1000 patients followed. 

Note: BMI ‐ Body Mass Index; CI ‐ Confidence Interval; GRADE ‐ Grading of Recommendations, Assessment, Development and Evaluations