Comparison of Clinical Features and Outcomes in Critically Ill Patients Hospitalized with COVID-19 versus Influenza

Abstract

Rationale: No direct comparisons of clinical features, laboratory values, and outcomes between critically ill patients with coronavirus disease (COVID-19) and patients with influenza in the United States have been reported. Objectives: To evaluate the risk of mortality comparing critically ill patients with COVID-19 with patients with seasonal influenza. Methods: We retrospectively identified patients admitted to the intensive care units (ICUs) at two academic medical centers with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or influenza A or B infections between January 1, 2019, and April 15, 2020. The clinical data were obtained by medical record review. All patients except one had follow-up to hospital discharge or death. We used relative risk regression adjusting for age, sex, number of comorbidities, and maximum sequential organ failure scores on Day 1 in the ICU to determine the risk of hospital mortality and organ dysfunction in patients with COVID-19 compared with patients with influenza. Results: We identified 65 critically ill patients with COVID-19 and 74 patients with influenza. The mean (±standard deviation) age in each group was 60.4 ± 15.7 and 56.8 ± 17.6 years, respectively. Patients with COVID-19 were more likely to be male, have a higher body mass index, and have higher rates of chronic kidney disease and diabetes. Of the patients with COVID-19, 37% identified as Hispanic, whereas 10% of the patients with influenza identified as Hispanic. A similar proportion of patients had fevers (∼40%) and lymphopenia (∼80%) on hospital presentation. The rates of acute kidney injury and shock requiring vasopressors were similar between the groups. Although the need for invasive mechanical ventilation was also similar in both groups, patients with COVID-19 had slower improvements in oxygenation, longer durations of mechanical ventilation, and lower rates of extubation than patients with influenza. The hospital mortality was 40% in patients with COVID-19 and 19% in patients with influenza (adjusted relative risk, 2.13; 95% confidence interval, 1.24–3.63; P = 0.006). Conclusions: The need for invasive mechanical ventilation was common in patients in the ICU for COVID-19 and influenza. Compared with those with influenza, patients in the ICU with COVID-19 had worse respiratory outcomes, including longer duration of mechanical ventilation. In addition, patients with COVID-19 were at greater risk for in-hospital mortality, independent of age, sex, comorbidities, and ICU severity of illness.

The incidence of pleural effusion in COVID-19 pneumonia: State-of-the-art review

“… 27 In contrast, a multi-center, retrospective, ICU study by Cobb et al reported that the incidence of pleural effusions was no different (11.1% versus 13.7%; p = 0.65) when comparing COVID-19 patients, and influenza A and B patients admitted over a similar timeframe. 45 …”

A Comparative Systematic Review of COVID-19 and Influenza

“…On PubMed, 331 articles were initially found, out of which 46 articles were selected. In the end, 18 articles were selected [3,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] (8 retrospective studies, 6 cohort studies, 3 casecontrol studies, 1 prospective study, 1 cross-sectional study, 1 review and meta-analysis, and 1 review) ( Figure 1 and Table 1) An outcome-free study population is first identified by the exposure/event of interest and followed in time until the outcome of interest happens. They can be prospective (carried out from the present time into the future) or retrospective (carried out at the present time and look to the past to examine medical events or outcome).…”

“…In this review, 14 studies of 18 [5,6,[9][10][11][12][13][14][15][16][18][19][20][21] reported a comparison between COVID-19 and influenza patients based on demographic findings, comorbidities, clinical features, and outcome (Table 2). Fever and respiratory symptoms such as cough, expectoration or sputum production and dyspnea were the main symptoms in both groups with COVID-19 and influenza; however, they were significantly more frequent in patients with influenza [5,[9][10][11]13,15,16,19,20].…”

“…Moreover, vomiting, otorhinolaryngological symptoms such as nasal congestion, rhinorrhea, sore throat and ocular symptoms such as tearing and conjunctival hyperhemia were statistically more frequent in patients with influenza than COVID-19 adult patients [5,[10][11][12]15]. In patients infected with COVID-19, the most significant and frequent clinical features were fatigue, neurologic symptoms such as headache (especially facial headache: retro-orbital or frontal headache), anosmia and dysgeusia, gastro-intestinal (GI) symptoms such as diarrhea and acute respiratory distress syndrome (ARDS), compared to influenza patients [11,[13][14][15]18]. In a retrospective case-control study, Tang et al reported that patients with influenza were more disposed to have productive cough and higher Sequential Organ Failure Assessment (SOFA) scores (OR = 9.58, (95% CI = 1.73-64.72), p = 0.011 and OR = 2.26 (1.12-3.57), p = 0.006, respectively).…”

Increased complement activation is a distinctive feature of severe SARS-CoV-2 infection

“…For example, although certain cytokines such as IL-6, G-CSF, IL-1RA, and MCP-1 predict death in COVID-19, their circulating levels are no different when measured in patients with other viral infections, such as influenza (Mudd et al ., 2020). However, the clinical presentation and autopsy findings of patients with COVID-19 indicate that in at least some of these patients, there may be a distinct immunological response, which is responsible for the mortality rate in excess of other viral illnesses (i.e., influenza) (Cobb et al ., 2020; Xie et al ., 2020), and results in certain coagulopathic events such as microscopic and macroscopic thrombi occurring more commonly in COVID-19 (Ackermann et al ., 2020; Bradley et al ., 2020; Carsana et al ., 2020; Fox et al ., 2020; Mei et al ., 2020). Understanding the underlying mechanisms of these relatively unique aspects of COVID-19 is crucial for targeting therapies, and, may provide insights into the pathogenesis of acute respiratory distress syndrome on a broader scale.…”