Hur 2020.

Study characteristics
Notes	English title Factors associated with intubation and prolonged intubation in hospitalized patients with COVID‐19 Study setting Start of study recruitment (MM/YYYY): 03/2020 End of study recruitment (MM/YYYY): 04/2020 Study design: Retrospective cohort Study centre(s): Multiple centres/clinics/areas within a country Number of centres, clinics or areas: 10 Study setting: Inpatient Number of participants recruited: 486 Sampling method: NR Participants Female participants (absolute number): 215 Age measure, value: Median (IQR), 59 (47‐69) Inclusion criteria: Age more than 18 years and were admitted to any of the 10 hospitals in the Northwestern Memorial HealthCare system spread across the Chicago metropolitan area between March 1 and April 8, 2020 Exclusion criteria: Hospitalised patients with documented ‘‘do not resuscitate and do not intubate’’ (DNR/DNI) orders and those who left the hospital against medical advice, and patients who had missing data on investigated predictor variables and did not reach a clinical endpoint of intubation or discharge from the hospital Smoking frequency: 163 Diabetes frequency: 160 Hypertension frequency: 267 Cardiovascular disease frequency: 111 Asthma frequency: NR Chronic obstructive pulmonary disease frequency: NR Other pulmonary disease frequency: 78 Immunosuppression frequency: 45 Chronic kidney disease frequency: 42 Cancer frequency: 60 Steroid administration frequency: NR Supplemental oxygen administration frequency: 326 Other treatments (frequency): Antibiotics (329), hydroxychloroquine (268), IL‐6R inhibitor (33), remdesivir (9) Prognostic factor(s) Study’s definition for obesity: BMI ≥ 30 kg/m2 The time when obesity has been measured: Before disease or right at presentation Main variable used for determination of obesity: BMI Threshold used for definition: 30 Obesity frequency (absolute number): 259 Prognostic factor(s): BMI 30‐39.99 BMI > 40 Outcome(s) Mechanical ventilation Time to extubation Outcome (prognostic factor) Mechanical ventilation (BMI 30‐39.99) Follow‐up Number of patients followed completely for the outcome: 468 Number of obese patients followed completely for the outcome: 259 Number of non‐obese patients followed completely for the outcome: 227 Univariable unadjusted analysis for obesity Effect measure for obesity: NR Effect measure value (95% CI), P value: NR Multivariable analysis for obesity Modelling method: Logistic regression The set of prognostic factors used for adjustment: Age, sex, race and ethnicity, hospital, body mass index, respiratory rate temperature, O2 sat, pulse, DM, shortness of breath Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 1.46 (0.87, 2.46), 0.151 Outcome (prognostic factor) Mechanical ventilation (BMI > 40) Follow‐up Number of patients followed completely for the outcome: 468 Number of obese patients followed completely for the outcome: 259 Number of non‐obese patients followed completely for the outcome: 227 Univariable unadjusted analysis for obesity Effect measure for obesity: NR Effect measure value (95% CI), P value: NR Multivariable analysis for obesity Modelling method: Logistic regression The set of prognostic factors used for adjustment: Age, sex, race and ethnicity, hospital, body mass index, respiratory rate temperature, O2 sat, pulse, DM, shortness of breath Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 1.92 (1.92, 4.00), 0.080 Outcome (prognostic factor) Time to extubation (BMI 30‐39.99) Follow‐up Number of patients followed completely for the outcome: 468 Number of obese patients followed completely for the outcome: 259 Number of non‐obese patients followed completely for the outcome: 227 Univariable unadjusted analysis for obesity Effect measure for obesity: NR Effect measure value (95% CI), P value: NR Multivariable analysis for obesity Modelling method: Cox regression The set of prognostic factors used for adjustment: Age, sex, race and ethnicity, hospital, body mass index, respiratory rate temperature, O2 sat, pulse, DM, shortness of breath Effect measure for obesity: Hazard ratio Effect measure value (95% CI), P value: 0.53 (0.32, 0.90), 0.018 Outcome (prognostic factor) Time to extubation (BMI > 40) Follow‐up Number of patients followed completely for the outcome: 468 Number of obese patients followed completely for the outcome: 259 Number of non‐obese patients followed completely for the outcome: 227 Univariable unadjusted analysis for obesity Effect measure for obesity: NR Effect measure value (95% CI), P value: NR Multivariable analysis for obesity Modelling method: Cox regression The set of prognostic factors used for adjustment: Age, sex, race and ethnicity, hospital, body mass index, respiratory rate temperature, O2 sat, pulse, DM, shortness of breath Effect measure for obesity: Hazard ratio Effect measure value (95% CI), P value: 0.40 (0.19, 0.82), 0.012
Item	Authors' judgement	Support for judgement
Study Participation	Yes	Appendix 3
Study Attrition Mechanical ventilation	Yes	Appendix 3
Prognostic Factor Measurement	Unclear	Appendix 3
Outcome Measurement Mechanical ventilation	Unclear	Appendix 3
Confounding Bias Mechanical ventilation	Unclear	Appendix 3
Statistical Analysis Bias	Yes	Appendix 3