The Utility of Blood Based Biomarkers in Detecting Neurological Complications of COVID‐19 in Critically Ill Patients

Background Neurological and neuropsychiatric complications have been documented in patients with COVID‐19. This study aims to investigate the utility of two neurological blood‐based biomarkers to predict neurological complications and mortality due to COVID‐19 in the intensive care unit (ICU). Neurofilament light (NF‐L) is a marker of axonal damage and glial fibrillary acidic protein (GFAP) is a marker of astrocytic activation. Methods Patients with respiratory failure were prospectively enrolled from the ICU at Vancouver General Hospital. COVID‐19 patients were excluded if the diagnosis was an incidental secondary finding upon ICU admission or if their enrollment was >10 days after ICU admission. Control patients were excluded if their enrollment was >4 days after ICU admission or if their primary diagnosis was non‐respiratory. Plasma samples were collected upon admission study enrollment, with additional samples collected on day 7 and day 14 from COVID‐19 patients. Plasma NF‐L and GFAP were quantified using the Quanterix Simoa HD‐X analyzer. Group comparisons were performed using a Mann‐Whitney test. Trajectory analysis was performed using a Wilcoxon test or Friedman one‐way ANOVA. Area under receiver operating curve (AUROC) analysis was calculated to predict neurological complications and mortality during ICU stay. Results Of the 242 patients enrolled, 209 were confirmed positive for SARS‐CoV‐2 while 33 served as ICU controls. Median age was 61 years for the COVID‐19 group, 64 years for controls. Upon ICU admission, NF‐L was 32% lower and GFAP was 24% lower in those with COVID‐19 compared to controls after correcting for age. NF‐L concentrations increase by doubling each week of ICU stay, while GFAP remained stable. Over the course of their ICU stay, 16% COVID‐19 patients were diagnosed with a neurological complication and 17% died. Plasma NF‐L and GFAP demonstrated a moderate to strong ability to predict neurological complications (AUROC: NF‐L=0.702;GFAP=0.722) and mortality (AUROC: NF‐L=0.815;GFAP=0.809) during ICU stay. Conclusions Upon ICU admission, NF‐L and GFAP were lower in patients with COVID‐19 compared to controls. NF‐L, but not GFAP, increased over the course of ICU stay in patients with COVID‐19. Both markers were able to predict neurological complication or ICU mortality with moderate to strong accuracy.

Quantification of neurological blood-based biomarkers in critically ill patients with COVID-19

Abstract Background Multiple neurological manifestations of COVID-19 have been reported such as headache, anosmia, ischemic stroke, and cerebral hemorrhages. Objective characterization of the acute neurological damage in critically ill patients with COVID-19 has not yet been reported. Method We performed a prospective observational study of plasma brain biomarkers in critically ill patients with respiratory failure that were diagnosed with (COVID-19) or without (ICU control) COVID-19. Demographics, co-morbidities, daily clinical physiologic and laboratory data were collected. Plasma samples were drawn for measurement of neurofilament-light chain (NF-L), total tau (t-tau), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), and glial fibrillary acidic protein (GFAP). The primary neurological outcome was delirium as defined by the intensive care delirium screening checklist (ICDSC, scale 1 - 8). Associations between brain biomarkers and markers of respiratory failure of COVID-19 were analyzed. Result 27 patients with COVID-19 and 19 ICU controls were enrolled. The concentration of plasma GFAP, UCH-L1 and NF-L levels was higher in both groups compared to healthy controls. Compared to ICU controls, patients with COVID-19 had significantly higher GFAP (272 [150-555] pg/ml vs 118 [78.5-168] pg/ml, p=0.0009). In patients with COVID-19, GFAP (rho=0.5115, p=0.0064), UCH-L1 (rho=0.4056, p=0.0358) and NF-L (rho=0.6223, p=0.0005) were positively correlated with the ICDSC score and were higher in patients diagnosed with delirium (ICDSC ≥4) in the COVID-19 group but not ICU controls. There were no associations between PaO2/FiO2 or diagnosis of ARDS and plasma concentration of GFAP, t-tau, UCH-L1, or NF-L in patients with COVID-19. Conclusion Plasma GFAP is 2-fold higher in critically ill patients with COVID-19 compared to ICU controls, and higher concentrations of GFAP, UCH-L1 and NF-L are associated with delirium specifically in patients with COVID-19.

Caractéristiques de départ et issues chez des patients atteints de COVID-19 hospitalisés dans des unités de soins intensifs à Vancouver (Canada) : série de cas.

CONTEXTE: La pandémie de maladie à coronavirus du syndrome respiratoire aigu sévère 2 (SRAS-CoV-2) est associée à une mortalité élevée dans les unités de soins intensifs (USI). Nous avons voulu décrire les caractéristiques cliniques et les issues des patients gravement atteints de la maladie à coronavirus 2019 (COVID-19) en contexte canadien. MÉTHODES: Nous avons procédé à l'étude rétrospective d'une série de cas graves d'infection au SRAS-CoV-2 confirmée en laboratoire hospitalisés dans l'une des 6 USI du Vancouver métropolitain, en Colombie-Britannique (Canada), entre le 21 février et le 14 avril 2020. Les données démographiques, les renseignements sur la prise en charge et les résultats ont été recueillis à partir des dossiers médicaux, électroniques ou non, des patients. RÉSULTATS: Entre le 21 février et le 14 avril 2020, 117 patients ont été admis dans une USI avec un diagnostic confirmé de COVID-19. L'âge médian était de 69 ans (écart interquartile [EI] 60­75 ans); et 38 (32,5 %) étaient des femmes. Au moins une comorbidité était présente chez 86 patients (73,5 %). La ventilation mécanique a été nécessaire chez 74 patients (63,2 %). La durée de la ventilation mécanique a été de 13,5 jours (EI 8­22 jours) dans l'ensemble et de 11 jours (II 6­16) chez les patients qui ont reçu leur congé de l'USI. Du tocilizumab a été administré à 4 patients et de l'hydroxychloroquine à 1 patient. En date du 5 mai 2020, 18 patients (15,4 %) étaient décédés, 12 (10,3 %) étaient toujours à l'USI, 16 (13,7 %) avaient obtenu leur congé de l'USI, mais restaient hospitalisés, et 71 (60,7 %) avaient pu retourner à la maison. INTERPRÉTATION: Dans cette étude, la mortalité chez les patients gravement malades de la COVID-19 hospitalisés dans une USI a été moins élevée que chez les patients d'études précédentes. Ces résultats donnent à penser que le pronostic des cas graves de COVID-19 pourrait ne pas être aussi sombre que ce qui avait d'abord été rapporté.

The association of ABO blood group with indices of disease severity and multiorgan dysfunction in COVID-19.

Studies on severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) suggest a protective effect of anti-A antibodies against viral cell entry that may hold relevance for SARS-CoV-2 infection. Therefore, we aimed to determine whether ABO blood groups are associated with different severities of COVID-19. We conducted a multicenter retrospective analysis and nested prospective observational substudy of critically ill patients with COVID-19. We collected data pertaining to age, sex, comorbidities, dates of symptom onset, hospital admission, intensive care unit (ICU) admission, mechanical ventilation, continuous renal replacement therapy (CRRT), standard laboratory parameters, and serum inflammatory cytokines. National (N = 398 671; P = .38) and provincial (n = 62 246; P = .60) ABO blood group distributions did not differ from our cohort (n = 95). A higher proportion of COVID-19 patients with blood group A or AB required mechanical ventilation (P = .02) and CRRT (P = .004) and had a longer ICU stay (P = .03) compared with patients with blood group O or B. Blood group A or AB also had an increased probability of requiring mechanical ventilation and CRRT after adjusting for age, sex, and presence of ≥1 comorbidity. Inflammatory cytokines did not differ between patients with blood group A or AB (n = 11) vs O or B (n = 14; P > .10 for all cytokines). Collectively, our data indicate that critically ill COVID-19 patients with blood group A or AB are at increased risk for requiring mechanical ventilation, CRRT, and prolonged ICU admission compared with patients with blood group O or B. Further work is needed to understand the underlying mechanisms.

Quantification of Neurological Blood-Based Biomarkers in Critically Ill Patients With Coronavirus Disease 2019.

OBJECTIVES: To provide an objective characterization of acute neurologic injury in critically ill patients with coronavirus disease 2019. DESIGN: Prospective observational study. Demographics, comorbidities, and daily clinical physiologic and laboratory data were collected. Plasma levels of neurofilament-light chain, total tau, ubiquitin carboxy-terminal hydrolase L1, and glial fibrillary acidic protein were measured. The primary neurologic outcome was delirium defined by the Intensive Care Delirium Screening Checklist (scale 1-8). Associations among plasma biomarkers, respiratory failure, and inflammation were analyzed. SETTING: Multicenter study in ICUs. PATIENTS: Critically ill patients with respiratory failure, with coronavirus disease 2019, or without (ICU control). MEASUREMENTS AND MAIN RESULTS: A total of 27 patients with coronavirus disease 2019 and 19 ICU controls were enrolled. Compared with ICU controls with pneumonia of other etiology, patients with coronavirus disease 2019 had significantly higher glial fibrillary acidic protein (272 pg/mL [150-555 pg/mL] vs 118 pg/mL [78.5-168 pg/mL]; p = 0.0009). In coronavirus disease 2019 patients, glial fibrillary acidic protein (rho = 0.5115, p = 0.0064), ubiquitin carboxy-terminal hydrolase L1 (rho = 0.4056, p = 0.0358), and neurofilament-light chain (rho = 0.6223, p = 0.0005) positively correlated with Intensive Care Delirium Screening Checklist score and were increased in patients with delirium (Intensive Care Delirium Screening Checklist ≥ 4) in the coronavirus disease 2019 group but not in ICU controls. There were no associations between the measures of respiratory function or cytokines with glial fibrillary acidic protein, total tau, ubiquitin carboxy-terminal hydrolase L1, or neurofilament-light chain levels in patients with coronavirus disease 2019. CONCLUSIONS: Plasma glial fibrillary acidic protein is two-fold higher in critically ill patients with coronavirus disease 2019 compared with ICU controls. Higher levels of glial fibrillary acidic protein, ubiquitin carboxy-terminal hydrolase L1, and neurofilament-light chain associate with delirium in patients with coronavirus disease 2019. Elevated plasma glial fibrillary acidic protein, ubiquitin carboxy-terminal hydrolase L1, and neurofilament-light chain are independent of respiratory function and peripheral cytokines.

The Association of Inflammatory Cytokines in the Pulmonary Pathophysiology of Respiratory Failure in Critically Ill Patients With Coronavirus Disease 2019.

OBJECTIVES: The majority of coronavirus disease 2019 mortality and morbidity is attributable to respiratory failure from severe acute respiratory syndrome coronavirus 2 infection. The pathogenesis underpinning coronavirus disease 2019-induced respiratory failure may be attributable to a dysregulated host immune response. Our objective was to investigate the pathophysiological relationship between proinflammatory cytokines and respiratory failure in severe coronavirus disease 2019. DESIGN: Multicenter prospective observational study. SETTING: ICU. PATIENTS: Critically ill patients with coronavirus disease 2019 and noncoronavirus disease 2019 critically ill patients with respiratory failure (ICU control group). INTERVENTIONS: Daily measurement of serum inflammatory cytokines. MEASUREMENTS AND MAIN RESULTS: Demographics, comorbidities, clinical, physiologic, and laboratory data were collected daily. Daily serum samples were drawn for measurements of interleukin-1ß, interleukin-6, interleukin-10, and tumor necrosis factor-α. Pulmonary outcomes were the ratio of Pao2/Fio2 and static lung compliance. Twenty-six patients with coronavirus disease 2019 and 22 ICU controls were enrolled. Of the patients with coronavirus disease 2019, 58% developed acute respiratory distress syndrome, 62% required mechanical ventilation, 12% underwent extracorporeal membrane oxygenation, and 23% died. A negative correlation between interleukin-6 and Pao2/Fio2 (rho, -0.531; p = 0.0052) and static lung compliance (rho, -0.579; p = 0.033) was found selectively in the coronavirus disease 2019 group. Diagnosis of acute respiratory distress syndrome was associated with significantly elevated serum interleukin-6 and interleukin-1ß on the day of diagnosis. CONCLUSIONS: The inverse relationship between serum interleukin-6 and Pao2/Fio2 and static lung compliance is specific to severe acute respiratory syndrome coronavirus 2 infection in critically ill patients with respiratory failure. Similar observations were not found with interleukin-ß or tumor necrosis factor-α.

Baseline characteristics and outcomes of patients with COVID-19 admitted to intensive care units in Vancouver, Canada: a case series.

BACKGROUND: Pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with high intensive care unit (ICU) mortality. We aimed to describe the clinical characteristics and outcomes of critically ill patients with coronavirus disease 2019 (COVID-19) in a Canadian setting. METHODS: We conducted a retrospective case series of critically ill patients with laboratory-confirmed SARS-CoV-2 infection consecutively admitted to 1 of 6 ICUs in Metro Vancouver, British Columbia, Canada, between Feb. 21 and Apr. 14, 2020. Demographic, management and outcome data were collected by review of patient charts and electronic medical records. RESULTS: Between Feb. 21 and Apr. 14, 2020, 117 patients were admitted to the ICU with a confirmed diagnosis of COVID-19. The median age was 69 (interquartile range [IQR] 60-75) years, and 38 (32.5%) were female. At least 1 comorbidity was present in 86 (73.5%) patients. Invasive mechanical ventilation was required in 74 (63.2%) patients. The duration of mechanical ventilation was 13.5 (IQR 8-22) days overall and 11 (IQR 6-16) days for patients successfully discharged from the ICU. Tocilizumab was administered to 4 patients and hydroxychloroquine to 1 patient. As of May 5, 2020, a total of 18 (15.4%) patients had died, 12 (10.3%) remained in the ICU, 16 (13.7%) were discharged from the ICU but remained in hospital, and 71 (60.7%) were discharged home. INTERPRETATION: In our setting, mortality in critically ill patients with COVID-19 admitted to the ICU was lower than in previously published studies. These data suggest that the prognosis associated with critical illness due to COVID-19 may not be as poor as previously reported.