Characteristics and Outcomes of US Patients Hospitalized With COVID-19

Ithan D. Peltan, MD, MSc; Ellen Caldwell, MS; Andrew J. Admon, MD, MPH, MSc; Engi F. Attia, MD, MPH; Stephanie J. Gundel, RD; Kusum S. Mathews, MD, MPH, MSCR; Alexander Nagrebetsky, MD, MSc; Sarina K. Sahetya, MD, MHS; Christine Ulysse, MS; Samuel M. Brown, MD, MS; Steven Y. Chang, MD, PhD; Andrew J. Goodwin, MD, MSc; Aluko A. Hope, MD, MSCE; Theodore J. Iwashyna, MD, PhD; Nicholas J. Johnson, MD; Michael J. Lanspa, MD; Lynne D. Richardson, MD; Kelly C. Vranas, MD, MCR; Derek C. Angus, MD, MPH; Rebecca M. Baron, MD; Benjamin A. Haaland, PhD; Douglas L. Hayden, PhD; B. Taylor Thompson, MD; Todd W. Rice, MD, MSc; Catherine L. Hough, MD, MSc


Am J Crit Care. 2022;31(2):146-157. 

In This Article


Among the 1480 patients included in our cohort, the median (IQR) age was 62.0 (49.4–72.9)years, 649 patients (43.9%) were female, and 822 of 1338 (61.4%) patients with known race/ethnicity were Hispanic/Latino or non-White (Table 1; Supplemental Table 2, available online only). The demographic profile of included patients was similar to that of the source population of all patients with COVID-19 admitted to study hospitals from March 1 to April 1, 2020 (Supplemental Table 3, available online only). Each of the 57 enrolling hospitals contributed a median (IQR) of 21 (8–41) patients. Most patients had at least 1 comorbidity included in the Charlson Comorbidity Index (n = 843; 57.0%). The median (IQR) preadmission symptom duration was 6 (3–9) days and was longer in survivors than in patients who died in the hospital (median [IQR], 7 [4–9] days vs 4 [2–7] days). The first-available Pao2 to FIO 2 ratio was less than 300 in 514 of 1452 patients (35.4%) with available data, and most patients (n = 1203; 81.3%) had a Sequential Organ Failure Assessment score of 2 or greater within 24 hours of hospital arrival (Supplemental Table 4, available online only).

Common pharmacologic treatments included hydroxychloroquine (54.3% of patients), azithromycin (65.4%), other antibiotics (78.6%), and therapeutic anticoagulation (23.6%) (Table 2). Systemic corticosteroid therapy was relatively rare (13.9%). Clinically diagnosed acute respiratory distress syndrome was the most common complication, affecting 483 patients (32.6%), including 200 of the 262 (76.3%) patients who died in the hospital (Supplemental Table 5, available online only). Among patients not receiving dialysis before admission, acute renal failure was also more common in nonsurvivors (148 of 249 patients; 59.4%) than in survivors (173 of 1188 patients; 14.6%). Venous thromboembolism was diagnosed in 46 patients (3.1%).

Overall, 575 patients (38.9%) received care in an ICU during their hospitalization. Of these, 369 (64.2%) were admitted to the ICU within 24 hours of hospital arrival (Supplemental Table 6, available online only). Most of the remaining ICU admissions occurred by hospital day 4 (Figure 2). More than four-fifths of patients (n = 1203; 81.3%) required some form of respiratory support during their hospital stay and 583 (39.4%) developed respiratory failure, including 413 (27.9%) who received invasive mechanical ventilation, 129 (8.7%) who received noninvasive positive pressure ventilation, and 254 (17.2%) who were treated with high-flow nasal cannula (Table 2). Respiratory failure occurred in 284 patients (19.2%) within 24 hours of hospital arrival. Among the 567 (38.3%) patients who required advanced organ-support therapies (high-flow nasal cannula, positive pressure ventilation, renal replacement therapy, and/or vasopressors), mechanical ventilation plus vasopressor support was the most common combination (23.1%, Figure 3). The vast majority (85.0%) of patients who received invasive mechanical ventilation were also treated with vasopressors during their hospitalization.

Figure 2.

Hospital level of care from arrival at study hospital through discharge or hospital day 60. Alluvial diagram depicts patients' transitions between treatment intensity levels during their hospitalization and ends on study hospital discharge. Because patients were not followed up beyond hospital discharge, patients do not transition out of postdischarge status of home or facility.

Figure 3.

Organ support therapy combinations and associated hospital mortality among patients requiring organ support therapy. Includes 567 patients receiving at least 1 advanced organ support therapy.
Abbreviations: HFNC, high-flow nasal cannula; IMV, invasive mechanical ventilation; NIPPV, noninvasive positive pressure ventilation.

Many patients experienced prolonged hospitalization, with median (IQR) hospital stays of 8 (5–15) days (Supplemental Figure 2, available online only). On day 15 of hospitalization, 355 (24.0%) patients remained admitted; 117 (7.9%) patients remained admitted on hospital day 28. Hospitalizations were longer for patients admitted to an ICU than for patients not admitted to an ICU (median [IQR], 15 [9–24] days vs 6 [4–9] days).

Supplemental Figure 1.

Cross validation plots for (A) mortality, (B) early respiratory failure, and (C) late respiratory failure depict the relationship between tuning parameter (lambda) and the associated model's cross-validated area under the receiver operating characteristic curve (AUC), with lowess curves drawn to show the smoothed association.

Supplemental Figure 2.

Patients remaining in the hospital by intensive care unit (ICU) admission status and hospital day.

Hospital mortality was 17.7% (n = 262, Table 2). Mortality was higher among patients admitted to an ICU (35.5%) than among patients never admitted to an ICU (5.3%). Mortality correlated with the number of organ failures, occurring in 11 of 58 (19.0%) patients who received mechanical ventilation and had isolated respiratory failure, 111 of 254 (43.7%) intubated patients who also required vasopressor support, and 64 of 97 (66.0%) intubated patients who required both vasopressors and renal replacement therapy. Unadjusted hospital mortality was higher in older patients; men; patients with hypertension, diabetes, cancer, or chronic cardiovascular disease; and individuals admitted from a long-term care facility (Table 1; Supplemental Figure 3, available online only).

Supplemental Figure 3.

Unadjusted hospital mortality stratified by selected clinical and demographic parameters. Data shown are stratified mortality rate with binomial 95% confidence interval.

Penalized regression identified the following risk factors for mortality: older age, shorter reported interval from symptom onset to hospitalization, male sex, comorbidity burden, tachycardia, tachypnea, hypotension, abnormal mental status, hypoxemia, higher first-available creatinine level, and higher first-available white blood cell count (Table 3). Race/ethnicity was among the 4 candidate variables not identified as contributing risk factors for mortality. After multivariable regression, the risk of mortality increased exponentially with age, reaching an adjusted odds ratio of 30.7 (95% CI, 8.8–107.0) in patients 80 years and older compared with patients younger than 40 years. Adjusted odds ratios were similar in the sensitivity analysis reclassifying 12 patients discharged with hospice services as having the mortality outcome.

Fewer risk factors were identified for early respiratory failure. These risk factors included body mass index, dyspnea on presentation, initial respiratory rate, abnormal mental status, higher first-available creatinine level, higher first-available white blood cell count, and elevated first-available aspartate aminotransferase level (Supplemental Table 7, available online only). The adjusted odds of early respiratory failure were more than 4 times higher if the first-available Glasgow Coma Scale score was less than 15 (odds ratio, 4.69; 95% CI, 3.07–7.16). In contrast, risk factors identified for late respiratory failure and the magnitudes of the observed associations were similar to those identified for mortality (Supplemental Table 8, available online only). Chronic pulmonary disease was not identified as a risk factor for either early or late respiratory failure. Sensitivity analyses that excluded patients who died without meeting respiratory failure criteria or excluded face mask oxygen support from the definition of respiratory failure yielded similar results.

Among the 1218 survivors, the 221 (18.1%) patients who were prescribed at least 1 form of new respiratory support were older and experienced a higher incidence of respiratory failure during their hospitalization than did patients who did not receive new respiratory support (Supplemental Table 9, available online only). Discharge with new home-based or facility-based health care services occurred in 259 of the 1153 (22.5%) survivors initially admitted from home. Compared with survivors who were not discharged with new health care services, these patients were older and had more severe illness and longer hospitalizations (Supplemental Table 10, available online only). Ten of the 34 (29%) survivors who required new renal replacement therapy during their admission continued dialysis after discharge.