TABLE 2

Unadjusted hazard ratios (HRs) for 28-day mortality from the day of acute respiratory distress syndrome (ARDS) diagnosis

VariablesUnadjusted HR (95% CI)p-value
Influenza virus alone0.52 (0.31–0.89)0.02
Influenza virus and co-pathogen0.76 (0.83–1.56)0.46
Non-influenza virus pneumonia1.10 (0.83–1.46)0.49
Aspiration0.64 (0.41–0.99)0.048
Nonpulmonary sepsis2.40 (1.73–3.32)<0.001
Miscellaneous0.86 (0.55–1.34)0.51
Age, per 1-year increment1.023 (1.013–1.033)<0.0001
Male sex1.11 (0.83–1.60)0.24
Time of presentation to hospital to the ICU, per 1-day increment1.24 (0.64–1.86)0.59
Prognostic scores
 SAPS II at admission, per 1-point increment1.031 (1.024–1.038)<0.0001
 SOFA score on day 1 of ARDS, per 1-point increment1.213 (1.171–1.256)<0.0001
Coexisting condition
 Diabetes mellitus1.10 (0.72–1.68)0.67
 Valvular and/or coronary disease with treatment1.20 (0.84–1.72)0.31
 Aplasia and/or recent chemotherapy for solid tumour or haematological disease1.45 (1.06–2.01)0.02
 Cirrhosis2.05 (1.42–2.95)<0.0001
 COPD0.76 (0.53–1.07)0.14
 Obesity1.05 (0.77–1.44)0.75
MV
PaO2/FIO2 ratio#, per 1-mmHg increment0.990 (0.986–0.995)<0.0001
 Driving pressure#, per 1-point increment1.062 (1.035–1.089)<0.0001
Organ support and treatments
 Treatment with vasopressors2.88 (1.47–3.62)0.02
 Treatment with glucocorticoids1.58 (1.14–2.06)0.005
 Renal replacement therapy2.39 (1.84–3.18)<0.001
 Prone positioning0.86 (0.64–1.13)0.27
 Extracorporeal membrane oxygenation0.78 (0.45–1.29)0.34

ICU: intensive care unit; SAPS: Simplified Acute Physiology Score; SOFA: Sequential Organ Failure Assessment; MV: mechanical ventilation; PaO2: arterial oxygen tension; FIO2: inspiratory oxygen fraction. #: worst data recorded between 12 and 24 h of MV from the diagnosis of ARDS, after optimisation of MV.