Table 1.
Comparison of Baseline Variables in the Discovery and Replication Cohorts
| Variable | Discovery Cohort | Replication Cohort | Missing | P Value |
|---|---|---|---|---|
| Baseline characteristics | ||||
| Age, y | 63 (52-71) | 62 (52-71) | 0 (0) | .607 |
| Male sex | 1,418 (64.8) | 702 (63·1) | 0 (0) | .342 |
| Race | ... | ... | 0 (0) | < .001 |
| White | 755 (34.5) | 466 (41.9) | ... | ... |
| Black | 783 (35.8) | 260 (23.4) | ... | ... |
| Other | 161 (7.4) | 94 (8.5) | ... | ... |
| Unknown | 489 (22.3) | 292 (26.3) | ... | ... |
| Latino ethnicity | 360 (16.5) | 318 (28.6) | 0 (0) | < .001 |
| BMI, kg/m2 | 30 (26-36) | 30 (27-36) | 384 (11.6) | .927 |
| Diabetes | 913 (41.7) | 445 (40.0) | 0 (0) | .346 |
| Hypertension | 1,363 (62.3) | 673 (60.5) | 0 (0) | .322 |
| Kidney function (eGFRa), mL/min/1.73 m2 | ... | ... | 0 (0) | .867 |
| ≥ 90 | 684 (31.3) | 365 (32.8) | ... | ... |
| 60-< 90 | 789 (36.1) | 388 (34.9) | ... | ... |
| 30-< 60 | 454 (20.7) | 229 (20.6) | ... | ... |
| 15-< 30 | 104 (4.8) | 56 (5.0) | ... | ... |
| < 15 or RRT | 157 (7.2) | 74 (6.7) | ... | ... |
| Coronary artery disease | 309 (14.1) | 148 (13.3) | 0 (0) | .523 |
| Congestive heart failure | 227 (10.4) | 101 (9.1) | 0 (0) | .241 |
| Atrial fibrillation or flutter | 164 (7.5) | 72 (6.5) | 0 (0) | .282 |
| COPD | 175 (8.0) | 103 (9.3) | 0 (0) | .216 |
| Asthma | 238 (10.9) | 109 (9.8) | 0 (0) | .341 |
| Chronic liver disease | 74 (3.4) | 38 (3.4) | 0 (0) | .958 |
| HIV/AIDS | 31 (1.4) | 17 (1.5) | 0 (0) | .800 |
| Active malignancy | 102 (4.7) | 60 (5.4) | 0 (0) | .356 |
| Solid organ transplantation | 69 (3.2) | 37 (3.3) | 0 (0) | .789 |
| Bone marrow transplantation | 4 (0.2) | 4 (0.4) | 0 (0) | .329 |
| Blood type A | 433 (19.8) | 250 (22.5) | 0 (0) | .071 |
| Smoking status | ... | ... | 0 (0) | .419 |
| Never smoker | 1,245 (5.9) | 610 (54.9) | ... | ... |
| Current or former | 648 (29.6) | 336 (30.2) | ... | ... |
| Unknown | 295 (13.5) | 166 (14.9) | ... | ... |
| Preadmission ACEI or ARB | 729 (33.3) | 394 (35.4) | 0 (0) | .226 |
| Preadmission anticoagulation | 225 (10.3) | 98 (8.8) | 0 (0) | .179 |
| Preadmission immunosuppressive medication | 236 (10.8) | 106 (9.5) | 5 (0.2) | .255 |
| Clinical and laboratory data | ... | ... | ... | ... |
| Coinfection on ICU day 1 | 513 (23.5) | 213 (19.2) | 2 (0.1) | .005 |
| Altered mental status on ICU day 1 | 437 (20.0) | 320 (28.8) | 1 (< 0.1) | < .001 |
| Tmax ICU day 1, °F | 100.5 (99.1-102.0) | 100.4 (99.0-101.9) | 3 (0.1) | .058 |
| HRmax ICU day 1 | 105 (91-120) | 103 (90-119) | 3 (0.1) | .165 |
| SBPmin ICU day 1, mm Hg | 96 (85-111) | 97 (86-110) | 4 (0.1) | .156 |
| RRmax ICU day 1 | 32 (26-38) | 30 (25-36) | 0 (0) | < .001 |
| Respiratory support and oxygenation on ICU day 1 | ... | ... | 0 (0) | .624 |
| Neither HFNC, NIPPV, nor MVb | 266 (12.2) | 155 (13.9) | ... | ... |
| BPV, CPAP, HFNC, or NRBc | 494 (22.6) | 226 (20.3) | ... | ... |
| Vent P to F ratio | ||||
| > 300 | 347 (15.9) | 175 (15.7) | ... | ... |
| > 200-≤ 300 | 187 (8.5) | 104 (9.4) | ... | ... |
| > 100-≤ 200 | 486 (22.2) | 242 (21.8) | ... | ... |
| ≤ 100 | 397 (18.1) | 203 (18.3) | ... | ... |
| ECMO | 11 (0.5) | 7 (0.6) | ... | ... |
| No. of vasoactive infusions on ICU day 1 | 1 (0-1) | 1 (0-1) | 1,069 (33.4) | .024 |
| 24-h UOP on ICU day 1, mL/d | 700 (300-1,168) | 722 (324-1,300) | 1,537 (46.6) | .145 |
| WBC count, K/mm3 | 8.1 (5.9-11.3) | 8.4 (6.0-11.8) | 188 (5.7) | .129 |
| Lymphocyte, % | 10.1 (6.3-15.4) | 9.5 (5.4-14.7) | 613 (18.6) | .005 |
| Hemoglobin, g/dL | 12.6 (11.1-14.1) | 12.6 (11.0-13.9) | 193 (5.9) | .205 |
| Platelet count, K/mm3 | 210 (160-269) | 215 (166-274) | 204 (6.2) | .249 |
| Creatinine, mg/dL | 1.10 (0.80-1.69) | 1.04 (0.80-1.70) | 157 (4.8) | .608 |
| Albumin, g/dL | 3.2 (2.8-3.6) | 3.2 (2.8-3.5) | 638 (19.3) | .607 |
| AST, U/L | 54 (36-85) | 55 (36-85) | 631 (19.1) | .733 |
| ALT, U/L | 35 (23-58) | 37 (23-61) | 609 (18.5) | .190 |
| Total bilirubin, mg/dL | 0.6 (0.4-0.8) | 0.6 (0.4-0.8) | 615 (18.6) | .102 |
| Lactate, mM | 1.5 (1.1-2.3) | 1.5 (1.1-2.2) | 1,246 (37.8) | .742 |
| CRP, mg/L | 162 (97-243) | 144 (76-232) | 1,316 (39.9) | < .001 |
| Arterial pH | 7.37 (7.30-7.43) | 7.37 (7.30-7.43) | 1,036 (31.4) | .897 |
| D-dimer, ng/mL | 1,209 (660-2,815) | 1,600 (822-3,935) | 1,646 (49.9) | < .001 |
| Ferritin, ng/mL | 1,015 (488-1,979) | 1,077 (550-2,261) | 1,451 (44.0) | .024 |
| Procalcitonin, ng/mL | 0.38 (0.15-1.22) | 0.40 (0.14-1.72) | 1,319 (40.0) | .381 |
| CK, U/L | 210 (98-565) | 210 (97-505) | 1,795 (54.4) | .546 |
| Center and region data | ||||
| Total centers | 45 | 22 | ... | ... |
| Total patients | 2,188 (66.3) | 1,112 (33.7) | ... | ... |
| US regiond | ... | ... | ... | ... |
| Northeast | 1,088 (49.7) | 807 (72.6) | ... | ... |
| South | 249 (11.4) | 90 (8.1) | ... | ... |
| Midwest | 618 (28.2) | 155 (13.9) | ... | ... |
| West | 233 (10.6) | 60 (5.4) | ... | ... |
Data are presented as No. (%) or median (interquartile range), unless otherwise indicated. The discovery and replication cohorts were constructed by randomly choosing centers from all available STOP-COVID sites with a target patient split of approximately 2:1 between discovery and replication. Differences between cohorts were compared using the Kruskal-Wallis test and the χ 2 test, as appropriate. ACEI = angiotensin converting enzyme inhibitor; ALT = alanine aminotransferase; ARB = angiotensin receptor blocker; AST = aspartate aminotransferase; BPV = bilevel pressure ventilation; CK = creatine kinase; CRP = C-reactive protein; ECMO = extracorporeal membrane oxygenation; eGFR = estimated glomerular filtration rate; HFNC = high-flow nasal cannula; HRmax = maximum heart rate; MV = mechanical ventilation; NIPPV = noninvasive positive pressure ventilation; NRB = nonrebreather mask; P to F = partial pressure of arterial oxygenation to fraction of inspired oxygenation; RRmax = maximum respiratory rate; RRT = renal replacement therapy; SBPmax = maximum systolic BP; STOP-COVID = Study of Treatment and Outcomes in Critically Ill Patients with COVID-19; Tmax = maximum temperature; UOP = urine output.
Via the Chronic Kidney Disease Epidemiology Collaboration equation.
Includes patients who received supplemental oxygen by nasal cannula administration.
Ninety-two percent of patients in this category (n = 662 of 720) were receiving respiratory support via HFNC or nonrebreather mask on ICU day 1. The remaining 8% (n = 58 of 720) were receiving BPV or CPAP.
Regions comprise the following US states (only states that contributed to the STOP-COVID database are listed): (1) Northeast: Connecticut, Washington, DC, Massachusetts, Maryland, New Jersey, New York, and Pennsylvania; (2) South: Alabama, Florida, Louisiana, North Caroline, Tennessee, Texas, and Virginia; (3) Midwest: Illinois, Indiana, Kentucky, Michigan, Minnesota, Missouri, Ohio, Oklahoma, and Wisconsin; and (4) West: Arizona, California, Colorado, Nevada, Oregon, and Washington.