Early in the pandemic, COVID-19 was often compared with the flu. A study of veterans in hospital showed how different it was. Compared with patients hospitalized with influenza, those hospitalized with COVID-19 in the Veterans Health Administration (VHA) — the largest integrated health care system in the United States — had more than five times the risk of dying in the hospital, and higher risks for 17 respiratory and nonrespiratory complications.
Credit: CDC, Morbidity and Mortality Weekly Report*.*
The comparison
Researchers analyzed electronic health records of adults hospitalized in the VHA:
- 3,948 with COVID-19, confirmed by RT-PCR, March 1–May 31, 2020;
- 5,453 with influenza, laboratory-confirmed, October 1, 2018–February 1, 2020 (later flu cases were excluded to avoid patients who might also have had COVID-19).
They compared 33 acute complications, identified from diagnosis codes, adjusting for age, sex, race and ethnicity, and underlying conditions. COVID-19 patients were slightly older (median age 70 versus 69), but flu patients had more underlying conditions.
| Outcome | COVID-19 | Influenza |
|---|---|---|
| Died in hospital | 21.0% | 3.8% |
| Admitted to ICU | 36.5% | 17.6% |
| Median length of stay (days) | 8.6 | 3.0 |
| Pneumonia | 70.1% | 35.1% |
| Respiratory failure | 46.5% | 28.5% |
| Acute respiratory distress syndrome (ARDS) | 9.3% | 0.5% |
| Sepsis | 24.9% | 18.6% |
What COVID-19 did
Of COVID-19 patients, 76.8% had respiratory complications. Many also had renal (39.6%), cardiovascular (13.1%), hematologic (6.2%) or neurologic (4.1%) complications, sepsis (24.9%) or bacteremia (4.7%), and 24.1% had complications in three or more organ systems.
Adjusted for other factors, compared with flu patients, COVID-19 patients had:
- about 19 times the risk of ARDS (aRR 18.60), 3.5 times the risk of a collapsed lung (pneumothorax), twice the risk of pneumonia and 1.7 times the risk of respiratory failure;
- more than twice the risk of myocarditis (2.56), deep vein thrombosis (2.81), pulmonary embolism (2.10), bleeding in the brain (2.85), acute hepatitis or liver failure (3.13), bacteremia (2.46) and pressure ulcers (2.65);
- about twice the risk of stroke from cerebral ischemia or infarction, and significantly higher risks of cardiogenic shock, disseminated intravascular coagulation, acute kidney failure, starting dialysis and sepsis.
Lower risks: asthma and COPD flare-ups were about three times less likely with COVID-19. COVID-19 patients also had lower risks of heart attack, unstable angina and acute heart failure — but these differences vanished when patients diagnosed in the same months of the year were compared, suggesting seasonal variation in heart disease.
The authors link the pattern to what was known then: the frequent sepsis fits reports of a dysregulated immune response, blood-clotting complications fit earlier reports of COVID-19 clots, and pressure ulcers may come from long hospital stays and lying face-down (prone positioning).
Unequal complications
Among COVID-19 patients, nine complications were more common in racial and ethnic minority patients even after adjusting for age and underlying conditions.
| COVID-19 patients | White | Black | Hispanic | Other races |
|---|---|---|---|---|
| Sepsis | 20.2% | 27.4% | 27.1% | 33.3% |
| ARDS | 7.8% | 9.8% | 11.3% | 17.2% |
| Respiratory failure | 43.3% | 47.5% | 47.0% | 55.2% |
| Pneumonia | 63.8% | 73.0% | 76.5% | 73.6% |
Black, Hispanic and other non-White patients had higher risks of sepsis and respiratory, neurologic and renal complications than White patients. Age and underlying conditions could not fully explain the gaps, which may reflect social, environmental, economic and structural inequities; understanding them, the authors say, is urgently needed.
Limits
Diagnosis codes can miss or misclassify conditions; complications may have been missed in patients with less typical symptoms; the "other race" group was small; the flu seasons studied were of moderate severity; vaccination and treatments were not examined; and the analysis did not adjust for region or facility.
The takeaway: clinicians should watch hospitalized COVID-19 patients for a whole spectrum of complications, so they can intervene early to improve outcomes and reduce long-term disability.
Sources
Based on Jordan Cates, Cynthia Lucero-Obusan, Rebecca M. Dahl, et al., "Risk for In-Hospital Complications Associated with COVID-19 and Influenza — Veterans Health Administration, United States, October 1, 2018–May 31, 2020," Morbidity and Mortality Weekly Report, volume 69, Centers for Disease Control and Prevention, posted as an Early Release on October 20, 2020; a work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from www.cdc.gov
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