Table 1 Characteristics of study sample

Sociodemographic characteristics

Age (years), median [P25; P75]

65.0 [56.0;73.0]

62.0 [53.0;70.0]

71.5 [62.8;76.0]

< 0.001

491

Female, n (%)

155 (31.6%)

107 (30.9%)

48 (33.3%)

0.678

490

Body mass index (kg/cm²), median [P25; P75]

29.0 [26.1;32.7]

29.0 [26.1;33.5]

28.8 [26.0;31.1]

0.156

410

Smoking history, n (%)

0.676

472

Former

145 (30.7%)

100 (30.0%)

45 (32.4%)

Nonsmoker

289 (61.2%)

204 (61.3%)

85 (61.2%)

Current

38 (8.05%)

29 (8.71%)

9 (6.47%)

Comorbidities

Hypertension, n (%)

275 (56.0%)

179 (51.6%)

96 (66.7%)

0.003

491

Diabetes Mellitus, n (%)

137 (27.9%)

83 (23.9%)

54 (37.5%)

0.003

491

Obesity, n (%)

184 (37.5%)

146 (42.1%)

38 (26.4%)

0.002

491

Chronic cardiovascular disease, n (%)

66 (13.5%)

43 (12.4%)

23 (16.0%)

0.367

490

Chronic pulmonary disease, n (%)

59 (12.0%)

37 (10.7%)

22 (15.3%)

0.201

491

Chronic kidney disease, n (%)

40 (8.16%)

23 (6.63%)

17 (11.9%)

0.080

490

Disease chronology

Time since first symptoms to ICU admission (days), median [P25; P75]

9.00 [7.00;12.0]

9.00 [7.00;12.0]

8.00 [6.00;11.2]

0.167

491

Time since hospital admission to ICU admission (days), median [P25; P75]

2.00 [0.00;4.00]

2.00 [0.00;3.00]

2.00 [0.00;4.25]

0.449

491

Hospital stay (days), median [P25; P75]

25.0 [15.0;41.5]

27.0 [16.0;45.5]

22.0 [14.8;32.2]

0.029

491

ICU stay (days), median [P25; P75]

14.0 [7.00;27.5]

12.0 [6.00;27.0]

19.0 [11.8;28.0]

< 0.001

491

Blood gases and laboratory parameters at ICU admission

Oxygen saturation (%), median [P25; P75]

94.0 [90.0;97.0]

94.8 [91.5;97.0]

92.3 [87.0;96.0]

< 0.001

483

PaCO₂ (mmHg), median [P25; P75]

38.7 [33.2;45.0]

37.0 [33.0;45.0]

41.0 [34.3;50.6]

0.002

464

pH, median [P25; P75]

7.41 [7.35;7.45]

7.43 [7.37;7.46]

7.38 [7.28;7.44]

< 0.001

465

PaO₂/FiO₂, median [P25; P75]

107 [76.0;148]

109 [81.8;153]

100 [65.6;136]

0.008

449

Glucose (mg/dL), median [P25; P75]

159 [129;207]

154 [126;197]

174 [135;255]

0.001

486

Creatinine (mg/dL), median [P25; P75]

0.84 [0.70;1.15]

0.82 [0.69;1.04]

0.90 [0.70;1.40]

0.035

487

 C-reactive protein (mg/L), median [P25; P75]

121 [57.0;216]

114 [56.8;199]

150 [59.4;234]

0.147

472

D-dimer (ng/mL), median [P25; P75]

1023 [562;1898]

836 [484;1536]

1578 [976;3822]

< 0.001

451

Leukocyte count (x10⁹/L), median [P25; P75]

9.90 [7.20;13.8]

9.49 [6.95;13.0]

11.7 [8.06;15.8]

< 0.001

487

Neutrophil count (x10⁹/L), median [P25; P75]

8.90 [6.17;12.5]

8.30 [5.80;11.4]

10.6 [7.30;14.8]

< 0.001

468

Lymphocyte count (x10⁹/L), median [P25; P75]

0.63 [0.41;0.88]

0.68 [0.50;0.90]

0.54 [0.35;0.80]

< 0.001

477

Monocyte count (x10⁹/L), median [P25; P75]

0.40 [0.23;0.56]

0.40 [0.25;0.56]

0.34 [0.20;0.58]

0.179

465

Platelet count (x10⁹/L), median [P25; P75]

236 [185;307]

237 [190;304]

230 [165;317]

0.131

485

AST (U/L), median [P25; P75]

42.6 [29.0;68.0]

42.0 [29.0;68.0]

42.8 [29.0;68.3]

0.840

419

ALT (U/L), median [P25; P75]

41.0 [25.0;67.0]

42.5 [27.0;67.8]

35.5 [21.2;63.0]

0.019

448

Urea (mg/dL), median [P25; P75]

52.0 [38.0;73.0]

49.0 [35.0;68.0]

62.2 [46.2;94.0]

< 0.001

445

Severity scores at ICU admission

APACHE-II score, median [P25; P75]

12.0 [9.00;17.0]

11.0 [8.00;15.0]

15.0 [12.0;21.2]

< 0.001

356

SOFA Score, median [P25; P75]

5.00 [4.00;7.25]

5.00 [4.00;7.00]

7.00 [4.00;8.75]

< 0.001

380

Interventions during ICU stay

Antibiotics, n (%)

461 (94.1%)

321 (92.5%)

140 (97.9%)

0.037

490

Hydroxychloroquine, n (%)

32 (6.54%)

26 (7.49%)

6 (4.23%)

0.261

489

Tocilizumab, n (%)

125 (25.6%)

92 (26.5%)

33 (23.2%)

0.523

489

Corticoids, n (%)

483 (98.8%)

341 (98.6%)

142 (99.3%)

0.676

489

High flow oxygen nasal cannula, n (%)

347 (80.5%)

265 (84.9%)

82 (68.9%)

< 0.001

431

Noninvasive positive pressure ventilation, n (%)

144 (29.9%)

96 (28.2%)

48 (34.3%)

0.221

481

Invasive mechanical ventilation, n (%)

384 (78.4%)

247 (71.4%)

137 (95.1%)

< 0.001

490

Prone positioning, n (%)

277 (56.5%)

161 (46.4%)

116 (81.1%)

< 0.001

490