High Plasma Osteopontin Levels Are Associated with Serious Post-Acute-COVID-19-Related Dyspnea

COVID-19 survivors commonly report persistent symptoms. In this observational study, we investigated the link between osteopontin (OPN) and post-acute COVID-19 symptoms and lung functional/imaging abnormalities. We recorded symptoms and lung imaging/functional data from previously hospitalized COVID-19 patients, who were followed for 4-84 weeks (122 patients/181 visits) post-symptom onset at our outpatient clinic. Circulating OPN was determined using ELISA. Plasma OPN levels were higher in symptomatic patients (compared with the asymptomatic ones); those with dyspnea (compared with those without dyspnea);those with a combination of serious symptoms, i.e., the presence of at least one of the following: dyspnea, fatigue and muscular weakness (compared with those with none of these symptoms); and those with dyspnea and m-MRC > 1 (compared with those with m-MRC = 0-1). Plasma OPN levels were inversely correlated with EQ-VAS (visual analog scale of the EQ-5D-5L health-related quality-of-life questionnaire) values. High-resolution CT or diffusion lung capacity (DLCO) findings were not related to circulating OPN. In the multiple logistic regression, the presence of symptoms, dyspnea, or the combination of serious symptoms were linked to female gender, increased BMI and pre-existing dyspnea (before the acute disease), while increased plasma OPN levels, female gender and pre-existing dyspnea with m-MRC > 1 were independently associated with severe post-COVID-19 dyspnea (m-MRC > 1). Using a correlation matrix to investigate multiple correlations between EQ-VAS, OPN and epidemiological data, we observed an inverse correlation between the OPN and EQ-VAS values. Increased circulating OPN was linked to the persistence of severe exertional dyspnea and impaired quality of life in previously hospitalized COVID-19 patients.

Kinetics of Immune Subsets in COVID-19 Patients Treated with Corticosteroids

RATIONALE

Changes in anti-SARS-CoV-2 defense immune subsets in patients treated with dexamethasone (DXM) for severe COVID-19 and their relation to disease outcomes are poorly understood.

METHODS

Blood-lymphocyte subsets of 110 hospitalized COVID-19 patients were prospectively examined. A first sample was taken at enrollment and a second one 7-10 days later. Total B-, T-lymphocytes, CD4+, CD8+, T-regulatory (Treg), Natural-Killer (NK) and NK T-cells were counted using flow cytometry.

RESULTS

At enrollment, patients with respiratory failure, characterized by DXM failure (intubation/death) or DXM success (hospital discharge) exhibited significantly fewer CD3+, CD4+ and CD8+ cells and B-lymphocytes compared to the control group (no respiratory failure/no DXM). At the time of treatment completion, the DXM-failure group exhibited significantly fewer CD3+, CD4+ and CD8+ cells, memory CD4+ and CD8+ T-lymphocytes, compared to the control and the DXM-success groups and fewer activated CD4+ T-lymphocytes, Tregs and NK cells compared to the control group. At the time of treatment completion, the number of all investigated lymphocyte subsets increased in the DXM-success group and was similar to those of the control group. NK cells significantly decreased over time in the DXM-failure group.

CONCLUSION

The lymphocyte kinetics differ between DXM-treated and control COVID-19 patients and are associated with clinical outcomes.

Predictors of high flow oxygen therapy failure in COVID-19-related severe hypoxemic respiratory failure

Background

During COVID-19 pandemic, people who developed pneumonia and needed supplemental oxygen, where treated with low-flow oxygen therapy systems and non-invasive methods, including oxygen therapy using high flow nasal cannula (HFNC) and the application of bi-level or continuous positive airway pressure (BiPAP or CPAP). We aimed to investigate the outcomes of critical COVID-19 patients treated with HFNC and unveil predictors of HFNC failure.

Methods

We retrospectively enrolled patients admitted to COVID-19 wards and treated with HFNC for COVID-19-related severe hypoxemic respiratory failure. The primary outcome of this study was treatment failure, such as the composite of intubation or death during hospital stay. The association between treatment failure and clinical features was evaluated using logistic regression models.

Results

One hundred thirty-two patients with a median (IQR) PaO₂/FiO₂ ratio 96 (63-173) mmHg at HFNC initiation were studied. Overall, 45.4% of the patients were intubated. Hospital mortality was 31.8%. Treatment failure (intubation or death) occurred in 50.75% and after adjustment for age, gender, Charlson Comorbidity index (CCI) score and National Early Warning Score 2 (NEWS2) score on admission and PaO₂/FiO₂ ratio and acute respiratory distress syndrome (ARDS) severity at the time of HFNO initiation, it was significantly associated with the presence of dyspnea [adjusted OR 2.48 (95% CI: 1.01-6.12)], and higher Urea serum levels [adjusted OR 1.25 (95% CI: 1.03-1.51) mg/dL].

Conclusions

HFNC treatment was successful in almost half of the patients with severe COVID-19-related acute hypoxemic respiratory failure (AHRF). The presence of dyspnea and high serum Urea levels on admission are closely related to HFNC failure.