Table 1.

Characteristics of included studies

Study name (first author and year)	Study design	Study groups and patients’ number	Inclusion criteria	Treatment regimen	Duration of treatment	Follow-up duration
Bernard 1987	Multicenter randomized controlled trial	Total patients, 99 Steroids, 50 Placebo, 49	Adult patients having ARDS withPaO2 ≤ 7 0mmhg (with FiO2 at least 40%) or PaO2/PAO2 ≤ 0.3; bilateral diffuse infiltrates on chest radiography, PAWP ≤ 18mmhg regardless of PEEP level.	-Treatment started after ARDS onset. Methylprednisolone 30 mg every 6 h (4 doses only).	24 h	Until death or for 45 days
Meduri 1998	Multicenter randomized controlled trial	Total Patients, 24 Steroids, 16 Placebo, 8	Adult patients with hypoxemic respiratory failure diagnosed with ARDS, who were on mechanical ventilation for at least 7 days, with LIS of 2.5 or greater and less than 1-point reduction from day 1 of ARDS onset.	-Treatment started after 7 days of ARDS onset. -Methylprednisolone 2 mg/kg per day (2 mg/kg from day 1 to day 14; 1 mg/kg from day 15 to 21; 0.5 mg/kg from day 22 to day 28; 0.25 mg/day from day 28 to day 32).	32 days	Hospital length of stay.
Confalonieri 2005	Multicenter randomized controlled trial	Total patients, 46 Steroids, 22 Placebo, 23	Patients with clinical and radiographic evidence of pneumonia with bilateral or multi-lobar involvement and PaO2/FiO2 ratio less than 250.	-Treatment started after diagnosis. -Hydrocortisone 200 mg bolus followed by an infusion of 10 mg/h.	7 days	60 days
Annane 2006	Multicenter randomized controlled trial	Total patients, 177 Steroids, 85 Placebo, 92	Patients with septic shock and ARDS; bilateral infiltrates on chest radiography; PaO2/FiO2 ≤ 200, PAWP ≤ 18 mmhg; no left atrial hypertension.	-Treatment started after randomization which occurred within 8 h of disease onset. -Hydrocortisone 50 mg every 6 h and 9 alpha fludrocortisone 50 milligram orally once a day.	7 days	28 days
Steinberg 2006	Multicenter randomized control trial	Total patients, 180 Steroids, 89 Placebo, 91	Adult patients who had ARDS and mechanically ventilated for 7 to 28 days. PaO2/FiO2 ≤ 200 mmhg.	-Treatment started after 7 to 28 days of ARDS onset. -Methylprednisolone: bolus 2 mg/kg followed by 0.5 mg/kg every 6 h for 14 days and then 0.5 mg/kg every 12 hours for 7 days and then tapering over 4days.	21-25 days.	60 days
Meduri 2007	Multicenter randomized control trial	Total patients, 91 Steroids, 63 Placebo, 28	Adult intubated patients with early ARDS (≤ 72 h) defined by the American-European Consensus definition.	-Treatment started within 72 h of ARDS onset. -Methylprednisolone bolus dose of 1 mg/kg followed by an infusion of 1 mg/kg per day from day 1 to day 14; 0.5 mg/kg per day from day 15 to day 21; 0.25 mg/kg per day from day 22 to day 25; and 0.125 mg/kg per day from day 26 to day 28.	Up to 28 days	Hospital length of stay.
Tongyoo 2016	Single-center randomized controlled trial	Total patients, 197 Steroids, 98 Placebo, 99	Adult patients with severe sepsis or septic shock, intubated with ARDS (according to criteria of ARDS by the American European Consensus or by the berlin criteria as moderate to severe ARDS)	-Randomization within 12 h of ARDS onset. -Hydrocortisone 50 mg every 6 h for 7 days	7 days	28 days
Villar 2020	Multicenter randomized control trial	Total patients, 277 Steroids, 139 Placebo, 138	Adult intubated patients with acute onset of ARDS according to criteria of ARDS by the American European Consensus or by the berlin criteria as moderate to severe ARDS.	Dexamethasone 20 mg daily from day 1 to day 5, then 10 mg daily from day 6 to day 10.	10 days	60 days

ARDS acute respiratory distress syndrome, PaO2 partial pressure pf arterial oxygen, PAWP pulmonary artery wedge pressure, PEEP positive end expiratory pressure, LIS lung injury score, FiO2 fraction of inhaled oxygen, APACHE acute physiologic and chronic health evaluation, MMHG millimeter of mercury, MG milligram, KG kilogram