Table 1 Training and test sets characteristics
From: COVID-19 ICU mortality prediction: a machine learning approach using SuperLearner algorithm
“Training set” Model 1 (n = 1293) | “Training set” Models 2–3 (n = 656) | “Test set 1” (COVID-19 VENETO ICU Network) (n = 124) | “Test set 2” (IRCCS Ca’ Granda Ospedale Maggiore Policlinico) (N = 199) | |
|---|---|---|---|---|
Gender (m) | 78% (1002) | 78% (506) | 68% (84) | 75% (150) |
Age | 60/69/75 | 61/68/74 | 56/67/73 | 51/61/66 |
SOFA score | 3/4/7 | 3/4/6 | 4/6/8 | 4/5/7 |
Individual components of SOFA score | ||||
SOFA score: assessment of respiratory system (PaO2/FiO2): 0 | 5% (50) | 1% (7) | 0% (0) | 1% (2) |
1 | 1% (16) | 2% (13) | 2% (2) | 1% (2) |
2 | 29% (324) | 44% (278) | 44% (48) | 8% (16) |
3 | 34% (372) | 28% (179) | 29% (32) | 48% (94) |
4 | 31% (337) | 24% (153) | 24% (26) | 42% (83) |
SOFA Platelets (×103/μL): 0 | 90% (567) | 90% (567) | 52% (58) | |
1 | 6% (38) | 6% (38) | 21% (23) | |
2 | 3% (18) | 3% (18) | 27% (30) | |
3 | 0% (3) | 0% (3) | 0% (0) | |
4 | 1% (4) | 1% (4) | 0% (0) | |
SOFA Glasgow Coma Scale (GCS): 0 | 63% (400) | 63% (400) | 69% (75) | |
1 | 23% (148) | 23% (148) | 25% (27) | |
2 | 3% (17) | 3% (17) | 3% (3) | |
3 | 1% (7) | 1% (7) | 2% (2) | |
4 | 9% (60) | 9% (60) | 1% (1) | |
SOFA bilirubin (mg/dl or umol/L): 0 | 90% (571) | 90% (571) | 99% (108) | |
1 | 7% (46) | 7% (46) | 1% (1) | |
2 | 1% (9) | 1% (9) | 0% (0) | |
3 | 1% (4) | 1% (4) | 0% (0) | |
4 | 0% (2) | 0% (2) | 0% (0) | |
SOFA creatinine (mg/ml or umol/L): 0 | 82% (511) | 82% (511) | 86% (93) | |
1 | 13% (81) | 13% (81) | 10% (11) | |
2 | 3% (18) | 3% (18) | 4% (4) | |
4 | 2% (10) | 2% (10) | 0% (0) | |
SOFA mean arterial pressure or administration of vasoactive agents required: 0 | 68% (429) | 68% (429) | 83% (91) | |
1 | 7% (41) | 7% (41) | 1% (1) | |
2 | 4% (23) | 4% (23) | 0% (0) | |
3 | 15% (93) | 15% (93) | 11% (12) | |
4 | 7% ( 41) | 7% (41) | 5% (5) | |
Palliative Score (PS) | 70/100/100 | 70/100/100 | 60/90/100 | |
Individual components of PS | ||||
PS Ambulation: 30 | 2% (14) | 2% (14) | 0% (0) | |
40 | 0% (3) | 0% (3) | 0% (0) | |
50 | 2% (12) | 2% (12) | 2% (2) | |
70 | 14% (84) | 14% (84) | 21% (25) | |
100 | 82% (501) | 82% (501) | 78% (93) | |
PS Activity: 50 | 2% (13) | 2% (13) | 0% (0) | |
60 | 2% (12) | 2% (12) | 2% (2) | |
80 | 11% (64) | 11% ( 64) | 8% (10) | |
90 | 30% (177) | 30% (177) | 39% (46) | |
100 | 55% (323) | 55% (323) | 51% (60) | |
PS Self-Care: 30 | 1% (9) | 1% (9) | 0% (0) | |
40 | 2% (12) | 2% (12) | 0% (0) | |
50 | 3% (17) | 3% (17) | 2% (3) | |
60 | 14% (84) | 14% (84) | 27% (32) | |
100 | 80% (491) | 80% (491) | 71% (85) | |
PS Intake: 20 | 2% (13) | 2% (13) | 0% (0) | |
30 | 3% (16) | 3% (16) | 10% (12) | |
80 | 5% (29) | 5% (29) | 5% (6) | |
100 | 90% (550) | 90% (550) | 85% (101) | |
PS level of consciousness (LOC): 10 | 1% (7) | 1% (7) | 0% (0) | |
40 | 1% (7) | 1% (7) | 0% (0) | |
60 | 4% (26) | 4% (26) | 10% (12) | |
100 | 93% (573) | 93% (573) | 90% (108) | |
Charlson Comorbidity Index (CCI): 0 | 48% (616) | 44% (291) | 66% (82) | 60% (119) |
CCI distribution when > 0 | 1/2/3 | 1/2/3 | 1/2/3 | 1/1/2 |
Individual components of CCI | ||||
Liver disease: None | 96% (1246) | 96% (631) | 98% (121) | |
Mild | 2% (20) | 2% (14) | 2% (3) | |
Moderate-severe | 2% (27) | 2% (11) | 0% (0) | |
Diabetes mellitus: None or diet-controlled | 78% (1012) | 80% (522) | 82% (102) | |
Uncomplicated | 10% (127) | 15% (96) | 8% (10) | |
End-organ damage | 12% (154) | 6% (38) | 10% (12) | |
Tumor: None | 93% (1203) | 94% (617) | 96% (119) | |
Localized | 6% (77) | 5% (35) | 2% (3) | |
Metastatic | 1% (13) | 1% (4) | 2% (2) | |
Acute myocardial infarction: Yes | 12% (153) | 11% (73) | 3% (4) | |
Peripheral vascular disease: Yes | 13% (167) | 15% (98) | 13% (16) | |
Chronic heart failure: Yes | 8% (99) | 8% (50) | 4% (5) | |
Transient ischemic attack: Yes | 4% (54) | 4% (23) | 1% (1) | |
Dementia: Yes | 2% (32) | 1% (8) | 1% (1) | |
Chronic obstructive pulmonary disease: Yes | 10% (132) | 11% (71) | 2% (3) | |
Connective tissue disease: Yes | 3% (34) | 4% (24) | 2% (2) | |
Peptic ulcer disease: Yes | 2% (25) | 1% (6) | 0% (0) | |
Hemiplegia: Yes | 1% (15) | 1% (9) | 1% (1) | |
Leukemia: Yes | 1% (14) | 1% (6) | 0% (0) | |
Chronic kidney disease: Yes | 8% (104) | 9% (56) | 4% (5) | |
Lymphoma: Yes | 1% (14) | 1% (8) | 0% (0) | |
AIDS: Yes | 0% (4) | 0% (2) | 0% (0) | |
ICU stay | ||||
O2 therapy | 8% (104) | 16% (104) | 29% (36) | |
Non-invasive ventilation | 48% (626) | 44% (286) | 43% (53) | |
Invasive mechanical ventilation | 85% (1093) | 79% (521) | 61% (76) | |
Prone position | 62% (797) | 57% (374) | 64% (79) | |
Tracheostomy | 17% (226) | 15% (101) | 2% (3) | |
Re-intubation | 52% (38) | 0% (0) | 100% (2) | |
Extracorporeal membrane oxygenation | 3% (39) | 3% (17) | 1% (1) | |
Continuous venous-venous hemofiltration | 6% (73) | 5% (30) | 2% (3) | |
Vasoactive agents | 48% (621) | 41% (268) | 25% (31) | |
Re-admission in ICU | 1% (9) | 1% (9) | 0% (0) | |