Ferritin in the coronavirus disease 2019 (COVID-19): A systematic review and meta-analysis

Thambiah S, Masiman AD, Samsudin IN, Lai YY. Refractory hypoxia and saturation gap in a COVID-19 patient

Acquired methemoglobinemia, predominantly due to oxidizing medications occurs when heme iron in hemoglobin is oxidized from ferrous to ferric ion and binds oxygen irreversibly leading to functional anemia, cyanosis, and tissue hypoxia. We report a case of a 60-year-old man with multiple comorbidities who was diagnosed with coronavirus disease 2019 (COVID-19) and developed methemoglobinemia after consumption of prescribed supplements. He presented with dyspnea and cyanosis. An oxygen saturation gap with characteristic chocolate-brown arterial blood indicated methemoglobinemia. Outsourced methemoglobin (MetHb) was increased at 9.0%. Despite aggressive intervention, he succumbed to his illness. In this case, we discuss the pathophysiology of why some individuals, especially the elderly with COVID-19 are more susceptible to develop methemoglobinemia after possibly being exposed to oxidizing agents. Laboratory methods for assessing oxygen saturation, including pulse oximetry, arterial blood gas and co-oximetry are examined in relation to this case. The importance of considering a diagnosis of methemoglobinemia based on clinical and biochemical findings although MetHb assay or co-oximetry are not readily available is also emphasized.

Melatonin: a ferroptosis inhibitor with potential therapeutic efficacy for the post-COVID-19 trajectory of accelerated brain aging and neurodegeneration

The unprecedented pandemic of COVID-19 swept millions of lives in a short period, yet its menace continues among its survivors in the form of post-COVID syndrome. An exponentially growing number of COVID-19 survivors suffer from cognitive impairment, with compelling evidence of a trajectory of accelerated aging and neurodegeneration. The novel and enigmatic nature of this yet-to-unfold pathology demands extensive research seeking answers for both the molecular underpinnings and potential therapeutic targets. Ferroptosis, an iron-dependent cell death, is a strongly proposed underlying mechanism in post-COVID-19 aging and neurodegeneration discourse. COVID-19 incites neuroinflammation, iron dysregulation, reactive oxygen species (ROS) accumulation, antioxidant system repression, renin-angiotensin system (RAS) disruption, and clock gene alteration. These events pave the way for ferroptosis, which shows its signature in COVID-19, premature aging, and neurodegenerative disorders. In the search for a treatment, melatonin shines as a promising ferroptosis inhibitor with its repeatedly reported safety and tolerability. According to various studies, melatonin has proven efficacy in attenuating the severity of certain COVID-19 manifestations, validating its reputation as an anti-viral compound. Melatonin has well-documented anti-aging properties and combating neurodegenerative-related pathologies. Melatonin can block the leading events of ferroptosis since it is an efficient anti-inflammatory, iron chelator, antioxidant, angiotensin II antagonist, and clock gene regulator. Therefore, we propose ferroptosis as the culprit behind the post-COVID-19 trajectory of aging and neurodegeneration and melatonin, a well-fitting ferroptosis inhibitor, as a potential treatment.

Association of Coagulopathy and Inflammatory Biomarkers with Severity in SARS-CoV-2-Infected Individuals of the Al-Qunfudhah Region of Saudi Arabia

BACKGROUND

Identifying prognosticators/predictors of COVID-19 severity is the principal focus for early prediction and effective management of the disease in a time-bound and cost-effective manner. We aimed to evaluate COVID-19 severity-dependent alteration in inflammatory and coagulopathy biomarkers.

METHODS

A hospital-dependent retrospective observational study (total: n = 377; male, n = 213; and female, n = 164 participants) was undertaken. COVID-19 exposure was assessed by performing real-time PCR on nasopharyngeal (NP) swabs. Descriptive and inferential statistics were applied for both continuous and categorical variables using Rstudio-version-4.0.2. Pearson correlation and regression were executed with a cut-off of p < 0.05 for evaluating significance. Data representation by R-packages and ggplot2.

RESULTS

A significant variation in the mean ± SD (highly-sever (HS)/moderately severe (MS)) of CRP (HS/MS: 102.4 ± 22.9/21.3 ± 6.9, p-value < 0.001), D-dimer (HS/MS: 661.1 ± 80.6/348.7 ± 42.9, p-value < 0.001), and ferritin (HS/MS: 875.8 ± 126.8/593.4 ± 67.3, p-value < 0.001) were observed. Thrombocytopenia, high PT, and PTT exhibited an association with the HS individuals (p < 0.001). CRP was correlated with neutrophil (r = 0.77), ferritin (r = 0.74), and WBC (r = 0.8). D-dimer correlated with platelets (r = -0.82), PT (r = 0.22), and PTT (r = 0.37). The adjusted odds ratios (Ad-OR) of CRP, ferritin, D-dimer, platelet, PT, and PTT for HS compared to MS were 1.30 (95% CI -1.137, 1.50; p < 0.001), 1.048 (95% CI -1.03, 1.066; p < 0.001), 1.3 (95% CI -1.24, 1.49, p > 0.05), -0.813 (95% CI -0.734, 0.899, p < 0.001), 1.347 (95% CI -1.15, 1.57, p < 0.001), and 1.234 (95% CI -1.16, 1.314, p < 0.001), respectively.

CONCLUSION

SARS-CoV-2 caused alterations in vital laboratory parameters and raised ferritin, CRP, and D-dimer presented an association with disease severity at a significant level.

Association of interleukin-6, ferritin, and lactate dehydrogenase with venous thromboembolism in COVID-19: a systematic review and meta-analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) is frequntly accompanied by venous thromboembolism (VTE), and its mechanism may be related to the abnormal inflammation and immune status of COVID-19 patients. It has been proved that interleukin-6 (IL-6), ferritin and lactate dehydrogenase (LDH) may play an important role in the occurrence of VTE in COVID-19 infection. But whether they can server as predictors for VTE in COVID-19 is still unclear. In this study, we performed a systematic review and meta-analysis to compare IL-6, ferritin and LDH in VTE and non-VTE COVID-19 patients in order to shed light on the prevention and treatment of VTE.

METHODS

Related literatures were searched in PubMed, Embase, Web of Science, Google Scholar, China National Knowledge Infrastructure (CNKI), WANGFANG. COVID-19 patients were divided into VTE group and non-VTE group. Meta-analysis was then conducted to compare levels of IL-6, ferritin and LDH between the two groups.

RESULTS

We finally included and analyzed 17 literatures from January 2019 to October 2022. There was a total of 7,035 COVID-19 patients, with a weighted mean age of 60.01 years. Males accounted for 62.64% and 61.34% patients were in intensive care unit (ICU). Weighted mean difference (WMD) of IL-6, ferritin and LDH was 31.15 (95% CI: 9.82, 52.49), 257.02 (95% CI: 51.70, 462.33) and 41.79 (95% CI: -19.38, 102.96), respectively. The above results indicated that than compared with non-VTE group, VTE group had significantly higher levels of IL-6 and ferritin but similar LDH.

CONCLUSION

This systematic review and meta-analysis pointed out that elevated levels of IL-6 and ferritin were significantly possitive associated with VTE, thus could be used as biological predictive indicators of VTE among COVID-19 patients. However, no association was found between level of LDH and VTE. Therefore, close monitoring of changes in IL-6 and ferritin concentrations is of great value in assisting clinicans to rapidly identify thrombotic complications among COVID-19 patients, hence facilitating the timely effective managment. Further studies are required in terms of the clinical role of cytokines in the occurrence of VTE among COVID-19 infection, with more reliable systematic controls and interventional trials.

Novel COVID-19 biomarkers identified through multi-omics data analysis: N-acetyl-4-O-acetylneuraminic acid, N-acetyl-L-alanine, N-acetyltriptophan, palmitoylcarnitine, and glycerol 1-myristate

This study aims to apply machine learning models to identify new biomarkers associated with the early diagnosis and prognosis of SARS-CoV-2 infection.Plasma and serum samples from COVID-19 patients (mild, moderate, and severe), patients with other pneumonia (but with negative COVID-19 RT-PCR), and healthy volunteers (control) from hospitals in four different countries (China, Spain, France, and Italy) were analyzed by GC-MS, LC-MS, and NMR. Machine learning models (PCA and PLS-DA) were developed to predict the diagnosis and prognosis of COVID-19 and identify biomarkers associated with these outcomes.A total of 1410 patient samples were analyzed. The PLS-DA model presented a diagnostic and prognostic accuracy of around 95% of all analyzed data. A total of 23 biomarkers (e.g., spermidine, taurine, L-aspartic, L-glutamic, L-phenylalanine and xanthine, ornithine, and ribothimidine) have been identified as being associated with the diagnosis and prognosis of COVID-19. Additionally, we also identified for the first time five new biomarkers (N-Acetyl-4-O-acetylneuraminic acid, N-Acetyl-L-Alanine, N-Acetyltriptophan, palmitoylcarnitine, and glycerol 1-myristate) that are also associated with the severity and diagnosis of COVID-19. These five new biomarkers were elevated in severe COVID-19 patients compared to patients with mild disease or healthy volunteers.The PLS-DA model was able to predict the diagnosis and prognosis of COVID-19 around 95%. Additionally, our investigation pinpointed five novel potential biomarkers linked to the diagnosis and prognosis of COVID-19: N-Acetyl-4-O-acetylneuraminic acid, N-Acetyl-L-Alanine, N-Acetyltriptophan, palmitoylcarnitine, and glycerol 1-myristate. These biomarkers exhibited heightened levels in severe COVID-19 patients compared to those with mild COVID-19 or healthy volunteers.

Evaluation of various blood biomarkers associated with the outcomes of patients with COVID‑19 treated in intensive care units

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the resulting coronavirus disease 2019 (COVID-19) represented a global public health crisis and the most significant pandemic in modern times. Transmission characteristics, and the lack of effective antiviral treatment protocol and protective vaccines, pushed healthcare systems, particularly intensive care units (ICUs), to their limits and led to extreme quarantine measures to control the pandemic. It was evident from an early stage that patient stratification approaches needed to be developed to better predict disease progression. In the present study, the predictive value of clinical and blood biomarkers for the outcomes of patients with COVID-19 hospitalized in the ICU were investigated, taking age and sex into consideration. The present study analyzed blood samples from 3,050 patients with COVID-19 hospitalized in the ICU. The analysis revealed that the levels of procalcitonin, N-terminal pro-B-type natriuretic peptide, D-dimer, ferritin, liver enzymes, C-reactive protein and lactate dehydrogenase were increased and were associated with disease progression, resulting in a prolonged hospitalization period and severe COVID-19 related complications. Additionally, significant age and sex disparities among these biomarkers were documented and discussed in specific cases. On the whole, the results of the present study suggest a potential association of the demographic characteristics and blood biomarkers with prolonged hospitalization in the ICU and the mortality of patients with COVID-19.

Vitamin D Levels as a Marker of Severe SARS-CoV-2 Infection

The SARS-CoV-2 virus may cause severe infection, which is associated with diverse clinical manifestations. Vitamin D has immunomodulating properties and may enhance the body's defense system against invading pathogenic organisms. The aim was to assess 25(OH)D3 levels in patients hospitalized for severe infection from the SARS-CoV-2 virus and explore the relationship between 25(OH)D3 and outcomes. In a group of 88 patients hospitalized for severe infection from the SARS-CoV-2 virus and a control group matched for age and sex, the levels of 25(OH)D3 were analyzed. Levels of 25(OH)D3 were 17.36 ± 8.80 ng/mL (mean ± SD) compared with 24.34 ± 10.34 ng/mL in patients with severe SARS-CoV-2 infection and the control group, respectively, p < 0.001 (Student's t-test). 25(OH)D3 levels were significantly related to outcomes, i.e., survival as opposed to non-survival, as more patients with 25(OH)D3 deficiency (0-10 ng/mL) and insufficiency (10-20 ng/mL) had a fatal outcome as compared with those with vitamin D sufficiency (p < 0.001, chi-square test, p < 0.001, Fisher's exact test). Levels of 25(OH)D3 were inversely related to C-reactive protein (CRP), ferritin, d-dimer, and fibrinogen levels (p < 0.001, linear regression analysis, beta coefficient of variation, -0.176, -0.160, -0.178, and -0.158, respectively). Vitamin D deficiency observed in severe SARS-CoV-2 infection was related to disease outcomes.

Hematologic characteristics and coagulopathy in pregnancy with COVID-19 succeeding the first wave: a multicenter retrospective cross-sectional study

Background

Early reports have demonstrated an association of COVID-19 infection during pregnancy and postpartum period with coagulopathy and bleeding complications and indicated that pregnant people with COVID-19 are more likely to experience coagulopathy and venous thromboembolism. A recent report concerning such complications during the first wave of the pandemic was reassuring; however, no publications have evaluated these issues in the context of increased illness severity with the emergence of SARS-CoV-2 variants of concern.

Objectives

We performed a retrospective, multinational cohort study in Canada, Romania, and the United Kingdom, aiming to provide a comprehensive analysis of the hematologic test characteristics of pregnancies affected by COVID-19 after the first wave of the pandemic.

Results

Three-hundred-seventy patients were evaluated. Markers of inflammation and endothelial dysfunction were significantly elevated, in keeping with observations in the nonpregnant population. Reassuringly, despite more severe disease noted in succeeding waves of the pandemic, there was no significant evidence of COVID-19-associated coagulopathy, and overall, no association was demonstrated between isolated coagulation abnormalities and bleeding risk. Notably, fibrinogen below 2g/L was again linked with the risk of postpartum hemorrhage. Finally, venous thromboembolism risk was low but noted more frequently in those with severe illness despite thromboprophylaxis.

Conclusion

Our findings add valuable insights into the nature of hematologic test characteristics, bleeding, and thrombotic complications for those affected with COVID-19 in pregnancy, reassuring readers of the low incidence of bleeding and thrombotic complications but inviting further debate as to the degree of thromboprophylaxis that may benefit the subgroup with severe disease.

Association of COVID with Mycosis in General

BACKGROUND

The COVID-19 pandemic caused by SARS-CoV-2 is a respiratory disease which created havoc worldwide, was accompanied by another peculiar, otherwise rare, secondary fungal infection Mucormycosis which was observed at exceptionally high incidence in India during the second wave of COVID-19. The article explores possible links between the two infectious diseases to understand a higher-than-normal occurrence of Mucormycosis in COVID-19 patients. Coronavirus enters the patients through ACE-2 and many other receptors like- NRP-1, TfR, CD-126, and CD-26. Virus bind to cells possessing these receptors and affect their proper functioning, disturbing homeostatic metabolism and resulting in conditions like hyperglycemia, Diabetic Ketoacidosis (DKA), low serum pH, iron overload, anemia, hypoxia, and immunosuppression as explained in the article. All these outcomes provide a very supportive environment for the attack and spread of Mucormycosis fungi. The major receptor for Mucormycosis in humans is the GRP-78. Its expression is upregulated by coronavirus entry and by hyperferritinemia, hyperglycemia, and acidic conditions prevalent in COVID patients, thus providing an easy entry for the fungal species. Upregulation of GRP-78 furthermore damages pancreatic β-cells and intensifies hyperglycemia, showing quite a synergic relationship. Inordinate rise of Mucormycosis cases in India might be explained by facts like- India possessing a large proportion of diabetic patients, emergence of a very deadly strain of coronavirus- Delta strain, higher doses of steroids and antibodies used to treat patients against this strain, overburdened health care services, sudden much higher need of oxygen supply and use of industrial oxygen could explain the Mucormycosis outbreak observed in India during the second wave of COVID-19.

OBJECTIVE

The present review discusses the functional interdependence between COVID-19 and Mucormycosis and summarizes the possible synergic links between COVID and Mucormycosis.

CONCLUSION

The receptors and metabolic pathways affected by COVID-19 result in severe physiological conditions- hyperglycemia, DKA, anemia, iron overload, immunosuppression, and hypoxia. All these conditions not only increase the expression of GRP-78, the major receptor for entry of fungi but also play a crucial role in providing quality media for Mucormycosis fungus to establish and grow. Hence explains the fungal epidemic observed in India during the second wave of COVID-19 in India.

SuPAR, biomarkers of inflammation, and severe outcomes in patients hospitalized for COVID-19: The International Study of Inflammation in COVID-19

Severe coronavirus disease 2019 (COVID-19) is a hyperinflammatory syndrome. The biomarkers of inflammation best suited to triage patients with COVID-19 are unknown. We conducted a prospective multicenter observational study of adult patients hospitalized specifically for COVID-19 from February 1, 2020 to October 19, 2022. Biomarkers measured included soluble urokinase plasminogen activator receptor (suPAR), C-reactive protein, interleukin-6, procalcitonin, ferritin, and D-dimer. In-hospital outcomes examined include death and the need for mechanical ventilation. Patients admitted in the United States (US, n = 1962) were used to compute area under the curves (AUCs) and identify biomarker cutoffs. The combined European cohorts (n = 1137) were used to validate the biomarker cutoffs. In the US cohort, 356 patients met the composite outcome of death (n = 197) or need for mechanical ventilation (n = 290). SuPAR was the most important predictor of the composite outcome and had the highest AUC (0.712) followed by CRP (0.642), ferritin (0.619), IL-6 (0.614), D-dimer (0.606), and lastly procalcitonin (0.596). Inclusion of other biomarkers did not improve discrimination. A suPAR cutoff of 4.0 ng/mL demonstrated a sensitivity of 95.4% (95% CI: 92.4%-98.0%) and negative predictive value (NPV) of 92.5% (95% CI: 87.5%-96.9%) for the composite outcome. Patients with suPAR < 4.0 ng/mL comprised 10.6% of the cohort and had a 0.8% probability of the composite outcome. Applying this cutoff to the validation cohort yielded a sensitivity of 93.8% (90.4%-96.7%) and NPV of 95.5% (93.1%-97.8%) for the composite outcome. Among commonly measured biomarkers, suPAR offered stronger discriminatory ability and may be useful in triaging low-risk patients with COVID-19.

Plasma Insulin-like Growth Factor-Binding Protein-2 of Critically Ill Patients Is Related to Disease Severity and Survival

Insulin-like growth factor-binding protein (IGFBP)-2 regulates the bioactivity of the anabolic hormone's insulin-like growth factors, which are decreased in sepsis and contribute to the catabolic status of severely ill patients. The circulating levels of IGFBP-2 in critical illness have been rarely studied; therefore, we evaluated IGFBP-2 plasma levels in patients with systemic inflammatory response syndrome (SIRS) or sepsis as well as healthy controls. Our analysis of 157 SIRS/sepsis patients revealed higher plasma IGFBP-2 levels compared to 22 healthy controls. Plasma IGFBP-2 levels correlated positively with procalcitonin but not with C-reactive protein, interleukin-6, or the leukocyte count. Septic shock patients exhibited higher IGFBP-2 levels than those with SIRS. Bacterial or SARS-CoV-2 infection did not influence plasma IGFBP-2 levels. There was no difference in the IGFBP-2 levels between ventilated and non-ventilated SIRS/sepsis patients, and vasopressor therapy did not alter these levels. Dialysis patients had elevated plasma IGFBP-2 levels. Survivors had lower plasma IGFBP-2 levels than non-survivors. In conclusion, our study indicates that plasma IGFBP-2 levels are associated with disease severity, renal failure, and mortality in SIRS/sepsis patients.

Impact of SARS-CoV-2 infection in patients with cardiac amyloidosis: Results of a multicentre registry

BACKGROUND

Descriptions on impact of SARS-CoV-2 infection in patients with cardiac amyloidosis (CA) are lacking. Our aim was to describe the prognosis of those patients.

METHODS

Retrospective observational study of unvaccinated patients with CA who developed SARS-CoV-2 infection enrolled in eleven centres (March 2020 to May 2021). Descriptive analysis of basal characteristics, hospitalization, mortality, and severe clinical course was performed. Comparisons to a population-based control group were made.

RESULTS

Forty-one patients were identified. Most patients had wild-type transthyretin CA (61%) and were on NYHA Class II-III (80.5%). CA patients were commonly hospitalized (73.2%) and those were more symptomatic than outpatients (p=0.035). The 24.4% of CA patients died as consequence of SARS-CoV-2 infection. Patients with CA had an increased risk of hospitalization [OR 6.23 (3.05-12.74), p<0.001] and mortality [OR 2.18 (1.01-4.68), p=0.047] when compared to control population after adjustment by age and sex. After a medium follow-time of 311 days, 41.5% of the CA cohort died.

CONCLUSIONS

SARS-CoV-2 infection is associated with high mortality and hospitalization rates in patients with CA, which exceed that expected by their sex and advanced age.

It's in the blood: a review of the hematological system in SARS-CoV-2-associated COVID-19

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to an unprecedented global healthcare crisis. While SARS-CoV-2-associated COVID-19 affects primarily the respiratory system, patients with COVID-19 frequently develop extrapulmonary manifestations. Notably, changes in the hematological system, including lymphocytopenia, neutrophilia and significant abnormalities of hemostatic markers, were observed early in the pandemic. Hematological manifestations have since been recognized as important parameters in the pathophysiology of SARS-CoV-2 and in the management of patients with COVID-19. In this narrative review, we summarize the state-of-the-art regarding the hematological and hemostatic abnormalities observed in patients with SARS-CoV-2-associated COVID-19, as well as the current understanding of the hematological system in the pathophysiology of acute and chronic SARS-CoV-2-associated COVID-19.

High-Flow Nasal Oxygen for Severe COVID-19 Pneumonia in Greek Patients: A Prospective Observational Study

INTRODUCTION

High-flow nasal oxygen (HFNO) and prone positioning may improve outcomes of coronavirus disease 2019 (COVID-19) patients treated in the intensive care unit (ICU). The aim of this study was to describe outcomes following the timely application of HFNO and prone positioning in COVID-19 patients treated in a ward setting.

METHODS

The study included 89 prospectively recruited subjects at the COVID-19 ward unit of the University Hospital of Heraklion, Greece, between March and December 2020.

RESULTS

Seventy-four (83%) of the 89 subjects in the study had severe COVID-19. Of those, 33 (45%) required HFNO treatment and prone positioning and 15 (45%) were transferred to the ICU, with 4 of them being intubated. Severe COVID-19 and HFNO needs were associated with an increased pneumonia severity index (PSI) score on admission and a worse PaO2/FiO2 ratio. In multivariate analysis, PSI was the only independent predictor of subsequent HFNO needs (OR=1.022). Overall intubation and mortality rates were 5.6% and 3.4%, respectively.

CONCLUSION

This study shows that for patients with severe COVID-19 hospitalized in medical wards, standard COVID-19 treatment, along with the timely utilization of HFNO and prone positioning, resulted in excellent outcomes with fewer ICU admission rates.

Excess iron aggravates the severity of COVID-19 infection

Coronavirus disease-19 (COVID-19) can induce severe inflammation of the lungs and respiratory system. Severe COVID-19 is frequently associated with hyper inflammation and hyper-ferritinemia. High iron levels are known to trigger pro-inflammatory effects. Cumulative iron loading negatively impacts on a patients innate immune effector functions and increases the risk for infection related complications. Prognosis of severe acute respiratory SARS-CoV-2 patients may be impacted by iron excess. Iron is an essential co-factor for numerous essential cellular enzymes and vital cellular operations. Viruses hijack cells in order to replicate, and efficient replication requires an iron-replete host. Utilizing iron loaded cells in culture we evaluated their susceptibility to infection by pseudovirus expressing the SARS-CoV-2 spike protein and resultant cellular inflammatory response. We observed that, high levels of iron enhanced host cell ACE2 receptor expression contributing to higher infectivity of pseudovirus. In vitro Cellular iron overload also synergistically enhanced the levels of; reactive oxygen species, reactive nitrogen species, pro-inflammatory cytokines (IL-1β, IL-6, IL-8 & TNF-α) and chemokine (CXCL-1&CCL-4) production in response to inflammatory stimulation of cells with spike protein. These results were confirmed using an in vivo mouse model. In future, limiting iron levels may be a promising adjuvant strategy in treating viral infection.

From 'mental fog' to post-acute COVID-19 syndrome's executive function alteration: Implications for clinical approach

A common symptom of the neuropsychiatric Post-Acute COVID-19 syndrome (neuro-PACS) is the so called 'brain fog'. Patients describe the brain fog as problems with attention, memory and mental fatigue. Brain fog is experienced by 9-55% of people for months after having contracted SARS-CoV-2 virus. Several theories have been proposed to explain PACS's brain fog, including a neuroinflammatory hypothesis, but the hypothesis remains to be proven. Here, we examined inflammatory and immunological blood profile in a cohort of patients with PACS to investigate the association between executive functions and blood inflammatory markers. Executive function was assessed by the Trail Making Test (TMT) Part A and Part B, as well as the Barkley Deficits in Executive Functioning Scale (BDEFS), in 71 patients (36 men), average age of 40 years (range: 15-82, SD: 15.7). Impairment in executive functioning (BDEFS scores and TMT B scores) correlated with increased levels of Interleukin-6 (IL-6), fibrinogen and ferritin. Moreover, elevated levels of Il-6, fibrinogen, ferritin, tumor necrosis factor-alpha and C-reactive protein have been observed in PACS. These findings demonstrate that PACS is characterized by the presence of an immuno-inflammatory process, which is associated with diminished executive functioning. Here, we argue in favour of a shift from the non-descriptive definition of 'mental fog' to a characterization of a subtype of PACS, associated with alteration in executive functioning. Implication for clinical settings and prevention are discussed.

Characterisation of Ferritin-Lymphocyte Ratio in COVID-19

Introduction: The ferritin-lymphocyte ratio (FLR) is a novel inflammatory biomarker for the assessment of acute COVID-19 patients. However, the prognostic value of FLR for predicting adverse clinical outcomes in COVID-19 remains unclear, which hinders its clinical translation. Methods: We characterised the prognostic value of FLR in COVID-19 patients, as compared to established inflammatory markers. Results: In 217 study patients (69 years [IQR: 55-82]; 60% males), FLR was weakly correlated with CRP (R = 0.108, p = 0.115) and white cell count (R = -0.144; p = 0.034). On ROC analysis, an FLR cut-off of 286 achieved a sensitivity of 86% and a specificity of 30% for predicting inpatient mortality (AUC 0.60, 95% CI: 0.53-0.67). The negative predictive values of FLR for ruling out mortality, non-invasive ventilation requirement and critical illness (intubation and/or ICU admission) were 86%, 85% and 93%, respectively. FLR performed similarly to CRP (AUC 0.60 vs. 0.64; p = 0.375) for predicting mortality, but worse than CRP for predicting non-fatal outcomes (all p < 0.05). On Kaplan-Meier analysis, COVID-19 patients with FLR values > 286 had worse inpatient survival than patients with FLR ≤ 286, p = 0.041. Conclusions: FLR has prognostic value in COVID-19 patients, and appears unrelated to other inflammatory markers such as CRP and WCC. FLR exhibits high sensitivity and negative predictive values for adverse clinical outcomes in COVID-19, and may be a good "rule-out" test. Further work is needed to improve the sensitivity of FLR and validate its role in prospective studies for guiding clinical management.

A Review of Hematological Complications and Treatment in COVID-19

COVID-19, caused by SARS-CoV-2, and its variants have spread rapidly across the globe in the past few years, resulting in millions of deaths worldwide. Hematological diseases and complications associated with COVID-19 severely impact the mortality and morbidity rates of patients; therefore, there is a need for oversight on what pharmaceutical therapies are prescribed to hematologically at-risk patients. Thrombocytopenia, hemoglobinemia, leukopenia, and leukocytosis are all seen at increased rates in patients infected with COVID-19 and become more prominent in patients with severe COVID-19. Further, COVID-19 therapeutics may be associated with hematological complications, and this became more important in immunocompromised patients with hematological conditions as they are at higher risk of hematological complications after treatment. Thus, it is important to understand and treat COVID-19 patients with underlying hematological conditions with caution. Hematological changes during COVID-19 infection and treatment are important because they may serve as biomarkers as well as to evaluate the treatment response, which will help in changing treatment strategies. In this literature review, we discuss the hematological complications associated with COVID-19, the mechanisms, treatment groups, and adverse effects of commonly used COVID-19 therapies, followed by the hematological adverse events that could arise due to therapeutic agents used in COVID-19.

Seizures in COVID-19: the relationship between biomarkers and prognosis

OBJECTIVE

To assess the prevalence of seizure, associated risk factors, and prognosis in patients with SARS-CoV-2 infection and identify predictive biomarkers in SARS-CoV-2 patients with seizure.

METHODS

A cohort of 17,806 patients with SARS-CoV-2 infection admitted to two university hospitals in Adana between March 11, 2020 and January 1, 2021 was analyzed retrospectively. The patients' demographic characteristics, laboratory findings, and systemic and neurological symptoms at admission and on the day of seizure onset were evaluated.

RESULTS

Neurological findings were detected in 877 of the 17,806 patients. Of these, 45 patients (0.25%) had seizure (status epilepticus in 4/45 patients, 8.9%). Patients with seizure had a mean age of 55.3 years (range 17-88) and 57.8% were male. Seizure was more common in the 18-44 (24.4%) and ≥ 65 age groups (44.4%) and in those with multiple comorbidity. The case fatality rate for patients with seizure among all SARS-CoV-2 patients was 0.135% (95% CI 80.86-188.71). However, no patient with a previous diagnosis of epilepsy died during SARS-CoV-2 infection. High neutrophil, platelet, and ferritin levels and low lymphocyte and calcium levels on the day of seizure development compared to admission were associated with higher mortality (p = 0.004, 0.008, 0.028, 0003, and 0.002, respectively).

CONCLUSIONS

Seizures are not uncommon during SARS-CoV-2 infection, with a higher risk of mortality in older patients and those with higher inflammatory markers.

Association of vaccination status with the clinicobiochemical profile, hospital stay, and mortality in COVID-19: A case-control study

Background and Aims

The effectiveness of coronavirus disease 2019 (COVID-19) vaccines in reducing symptoms, disease advancement, complications, and mortality in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been well-established. This case-control study aimed to compare different blood parameters, and prognostic and survival outcomes of COVID-19 patients based on vaccination status.

Methods

We performed a case-control study that included hospitalized patients with COVID-19 at Tribhuvan University Teaching Hospital, Kathmandu, Nepal. Individuals who received vaccination were designated as cases and unvaccinated individuals as controls. Demographics, co-morbidity, clinical data, laboratory data, and disease outcomes were recorded for both groups. Multivariate, Cox, and linear regression were used for analysing blood parameters, hospital admission, survival, and hospital stay, respectively, between cases and controls.

Results

Out of 100 participants enrolled, 46 were vaccinated, and 54 weren't. At admission, ferritin and erythrocyte sedimentation rate (ESR) were significantly lower in cases. At discharge, cases showed a higher monocyte than controls. Ferritin, ESR, and d-imer showed excellent performance in determining the severity of symptoms. Significant correlation and regression of ferritin and ESR with the length of hospital stay was observed. Length of hospital stay was significantly lower in cases than in controls. No significant differences between cases and controls were observed in mortality.

Conclusion

COVID-19 vaccines effectively reduced hospitalization duration. Ferritin and ESR were significantly lower in vaccinated individuals and showed the best utility in monitoring the disease.

Biochemical Analysis of Ferritin and D-dimer in COVID-19 Survivors and Non-survivors

Background COVID-19 is a major cause of illness and mortality. The management of COVID-19-related illnesses might change if variables connected to their severity and the requirement for ICU admission could be found. The severity of COVID-19 might be efficiently predicted with several laboratory measures, such as ferritin levels and D-dimer analysis. Objectives This study aimed to evaluate the association between serum D-dimer and ferritin levels and their effects on mortality in patients with COVID-19. Methods This retrospective observational study included all patients with positive real-time polymerase chain reaction (RT-PCR) results for COVID-19 who were hospitalized in the Ministry of Health South Al-Qunfudah General Hospital between March and September 30, 2020. Their laboratory parameters, serum D-dimer, and ferritin levels were evaluated. IBM SPSS Statistics for Windows, Version 26.0 (released 2019; IBM Corp., Armonk, New York, United States) was used to analyze the data. Results A total of 318 COVID-19 patients were analyzed; 56.9% (n=181) were male and 43.1% (n=137) were female. Of these, 78.6% (n=250) survived, including 58% of men and 42% of women. The mean D-dimer was 2.1 mcg/mL (SD=3.16) and the mean ferritin was 698.59 ng/mL (SD=603.11). Non-recovered patients were substantially older (66.16 years old) and had higher D-dimer (5.46) mcg/mL and ferritin levels (992.96) ng/mL. Intubation length and gender did not affect survival. Of the non-survivors, 95.6% (n=239) were admitted to the ICU, and 50% (n=34) required mechanical ventilation. Conclusions COVID-19 infection mortality dramatically increased with older age and increased mean ferritin and plasma D-dimer values, which were significantly higher in COVID-19 non-survivors than in survivors. Therefore, assessing and monitoring these laboratory markers in the early stages of the disease may have a significant impact on preventing disease progression and death.

Thrombocytopenia is associated with a dysregulated host response in severe COVID-19

BACKGROUND

Thrombocytopenia is associated with increased mortality in COVID-19 patients.

OBJECTIVE

To determine the association between thrombocytopenia and alterations in host response pathways implicated in disease pathogenesis in patients with severe COVID-19.

PATIENTS/METHODS

We studied COVID-19 patients admitted to a general hospital ward included in a national (CovidPredict) cohort derived from 13 hospitals in the Netherlands. In a subgroup, 43 host response biomarkers providing insight in aberrations in distinct pathophysiological domains (coagulation and endothelial cell function; inflammation and damage; cytokines and chemokines) were determined in plasma obtained at a single time point within 48 h after admission. Patients were stratified in those with normal platelet counts (150-400 × 109/L) and those with thrombocytopenia (<150 × 109/L).

RESULTS

6.864 patients were enrolled in the national cohort, of whom 1.348 had thrombocytopenia and 5.516 had normal platelets counts; the biomarker cohort consisted of 429 patients, of whom 85 with thrombocytopenia and 344 with normal platelet counts. Plasma D-dimer levels were not different in thrombocytopenia, although patients with moderate-severe thrombocytopenia (<100 × 109/L) showed higher D-dimer levels, indicating enhanced coagulation activation. Patients with thrombocytopenia had lower plasma levels of many proinflammatory cytokines and chemokines, and antiviral mediators, suggesting involvement of platelets in inflammation and antiviral immunity. Thrombocytopenia was associated with alterations in endothelial cell biomarkers indicative of enhanced activation and a relatively preserved glycocalyx integrity.

CONCLUSION

Thrombocytopenia in hospitalized patients with severe COVID-19 is associated with broad host response changes across several pathophysiological domains. These results suggest a role of platelets in the immune response during severe COVID-19.

The predictive role of biochemical markers on outcomes of severe COVID-19 patients admitted to intensive care unit

Background

The pandemic of severe acute respiratory syndrome by coronavirus 2 (SARS-CoV-2) is a multi-system disease caused by a diffuse systemic process involving a complex interaction of the inflammatory, immunological and coagulative cascades. This study aims to identify the most effective biomarkers to predict poor outcome in intensive care unit (ICU) patients with severe COVID-19 disease.

Methods

A single-centre retrospective observational study enrolled 69 deceased and 20 recovered patients treated in the ICU of the General Hospital Gradiska in the period from March 1, 2021. until April 1, 2022. We evaluated the leukocytes (WBC), lymphocytes (LYM), neutrophils (NEU), platelets (PLT), haemoglobin, neutrophil-lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), and systemic immune-inflammation index (SII). In addition, we evaluated the IL-6, ferritin, CRP, D-dimer, magnesium, bilirubin and lactate dehydrogenase.

An analysis of reported cases of hemophagocytic lymphohistiocytosis (HLH) after COVID-19 vaccination

Although COVID-19 vaccines are an effective public health tool to combat the global pandemic, serious adverse events, such as hemophagocytic lymphohistiocytosis (HLH), caused by them are a concern. In this systematic review, cases of HLH reported after COVID-19 vaccination have been examined to understand the relationship between the two and propose effective therapeutic strategies. Furthermore, ruxolitinib's potential as a cytokine inhibitor and its affinity for CD25 were initially assessed through molecular docking, aiming to aid targeted HLH therapy. PubMed and Web of Science databases were searched for published individual case reports on the occurrence of HLH after the administration of any COVID-19 vaccine. A total of 17 articles (25 patients) were included in this qualitative analysis. Furthermore, molecular docking was employed to investigate the therapeutic potential of ruxolitinib for HLH after COVID-19 vaccination. The mean age of patients who developed HLH after COVID-19 vaccination was 48.1 years. Most HLH episodes occurred after the BNT162b2 mRNA COVID-19 vaccination (14/25 cases) and to an extent after the ChAdOx1 nCov-19 vaccination (5/25 cases). Almost all affected patients received steroid and antibiotic therapy. Three patients died despite treatment because of esophagus rupture, neutropenic fever, bacteroides bacteremia, refractory shock, and encephalopathy and shock. Visual docking results of IL-2 Rα and ruxolitinib using the Discovery Studio 2019 Client software yielded a model score of 119.879. The findings highlight the importance of considering and identifying the adverse effects of vaccination and the possibility of using ruxolitinib for treating HLH after COVID-19 vaccination.

Evaluation of iron metabolism in hospitalized COVID-19 patients

BACKGROUND

Iron metabolism dysregulation may play a role in organ failure observed in Coronavirus disease 2019 (COVID-19). This study aimed to explore the whole iron metabolism in hospitalized COVID-19 patients and evaluate the impact of tocilizumab.

METHODS

We performed an observational multicentric cohort study, including patients with PCR-provenCOVID-19 from the intensive care unit (ICU) (n = 66) and medical ward (n = 38). We measured serum interleukin-6 (IL-6), ferritin, glycosylated ferritin (GF), transferrin, iron, and hepcidin. The primary outcome was death.

RESULTS

Among the 104 patients, we observed decreased median GF percentage (35 %; IQ 23-51.5), low iron concentration (7.5 μmol/L; IQ 4-14), normal but low transferrin saturation (TSAT; 21%; IQ 11-33) and increased median hepcidin concentration (58.7 ng/mL; IQ 20.1-92.1). IL-6, ferritin, and GF were independently and significantly associated with death (p = 0.026, p = 0.023, and p = 0.009, respectively). Surprisingly, we observed a decorrelation between hepcidin and IL-6 concentrations in some patients. These findings were amplified in tocilizumab-treated patients.

CONCLUSION

Iron metabolism is profoundly modified in COVID-19. The pattern we observed presents differences with a typical inflammation profile. We observed uncoupled IL-6/hepcidin levels in some patients. The benefit of additive iron chelation therapy should be questionable in this setting.

Attenuation of ferroptosis as a potential therapeutic target for neuropsychiatric manifestations of post-COVID syndrome

Coronavirus disease-19 (COVID-19), caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), is associated with the persistence of pre-existing or the emergence of new neurological and psychiatric manifestations as a part of a multi-system affection known collectively as "post-COVID syndrome." Cognitive decline is the most prominent feature among these manifestations. The underlying neurobiological mechanisms remain under intense investigation. Ferroptosis is a form of cell death that results from the excessive accumulation of intracellular reactive iron, which mediates lipid peroxidation. The accumulation of lipid-based reactive oxygen species (ROS) and the impairment of glutathione peroxidase 4 (GPX4) activity trigger ferroptosis. The COVID-19-associated cytokine storm enhances the levels of circulating pro-inflammatory cytokines and causes immune-cell hyper-activation that is tightly linked to iron dysregulation. Severe COVID-19 presents with iron overload as one of the main features of its pathogenesis. Iron overload promotes a state of inflammation and immune dysfunction. This is well demonstrated by the strong association between COVID-19 severity and high levels of ferritin, which is a well-known inflammatory and iron overload biomarker. The dysregulation of iron, the high levels of lipid peroxidation biomarkers, and the inactivation of GPX4 in COVID-19 patients make a strong case for ferroptosis as a potential mechanism behind post-COVID neuropsychiatric deficits. Therefore, here we review the characteristics of iron and the attenuation of ferroptosis as a potential therapeutic target for neuropsychiatric post-COVID syndrome.

Association of D-Dimer, C-Reactive Protein, and Ferritin with COVID-19 Severity in Pregnant Women: Important Findings of a Cross-Sectional Study in Northern Brazil

BACKGROUND

The COVID-19 pandemic has had a great impact on pregnant women due to the broad clinical spectrum of the disease. The present study investigated the profile of three biomarkers during hospital admission of pregnant women-D-dimer, C-reactive protein (CRP), and ferritin-and their correlation with the severity and outcome of COVID-19.

METHODS

The cross-sectional study included 226 pregnant women hospitalized in the city of Belém, Pará, Northern Brazil, from April 2020 to July 2021. Epidemiological and laboratory data were obtained from medical records, and all pregnant women underwent RT-PCR molecular testing for the detection of SARS-CoV-2.

RESULTS

In total, 121 (53.5%) were positive and 105 (46.5%) were negative for SARS-CoV-2 using RT-PCR. Most pregnant women (49.5%) with COVID-19 were between 26 and 34 years old, were residing in the interior of the state of Pará (51.2%), and were in the third gestational trimester (71.9%). In addition, 71.1% of them were admitted to the ward and 28.9% were admitted to the intensive care unit (ICU), with 90.9% surviving COVID-19. The concentrations of D-dimer (p = 0.0122) and ferritin (p ≤ 0.0001) were significantly higher among pregnant women with COVID-19, especially among those hospitalized in the ICU.

CONCLUSION

Ferritin and D-dimer seem to serve as important biomarkers for the prognosis of COVID-19 in pregnant women, which was not observed for CRP.

Utility of Serum Ferritin for Predicting Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in Patients with Long COVID

OBJECTIVE

The most common symptom of post-acute coronavirus disease 2019 (COVID-19) is fatigue, and it potentially leads to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS); however, a specific prognosticator is lacking. We aimed to elucidate the clinical characteristics of patients who developed ME/CFS after COVID-19.

METHODS

In this retrospective observational study, patients who visited Okayama University Hospital for long COVID between February 2021 and March 2022 were investigated.

RESULTS

Of the 234 patients, 139 (59.4%) had fatigue symptoms. Fifty patients with fatigue symptoms (21.4%) met the criteria for ME/CFS (ME/CFS group), while the other 89 patients did not (non-ME/CFS group); 95 patients had no fatigue complaints (no-fatigue group). Although the patients' backgrounds were not significantly different between the three groups, the ME/CFS group presented the highest scores on the self-rating symptom scales, including the Fatigue Assessment Scale (FAS), EuroQol, and the Self-Rating Depression Scale (SDS). Furthermore, serum ferritin levels, which were correlated with FAS and SDS scores, were significantly higher in the ME/CFS group (193.0 μg/L, interquartile range (IQR): 58.8-353.8) than in the non-ME/CFS group (98.2 μg/L, 40.4-251.5) and no-fatigue group (86.7 μg/L, 37.5-209.0), and a high serum ferritin level was prominent in female patients. Endocrine workup further showed that the ME/CFS group had higher thyrotropin levels but lower growth hormone levels in serum and that insulin-like growth factor-I levels were inversely correlated with ferritin levels (R = -0.328, p < 0.05).

CONCLUSIONS

Serum ferritin level is a possible predictor of the development of ME/CFS related to long COVID, especially in female patients.

Normoferremia in Patients with Acute Bacterial Infections-A Hitherto Unexplored Field of the Dichotomy between CRP and Ferritin Expression in Patients with Hyper Inflammation and Failure to Increase Ferritin

Ferritin is an acute phase response protein, which may not rise as expected in acute bacterial infections. This could be due to the time required for its production or to a lack of response of ferritin to the bacterial inflammatory process. Medical records of hospitalized patients with acute hyper inflammation were retrieved and studied, looking closely at two acute phase proteins: C-reactive protein (CRP) and ferritin. The estimated time between symptom onset and the procurement of blood tests was also measured. 225 patients had a median ferritin level of 109.9 ng/mL [IQR 85.1, 131.7] and a median CRP level of 248.4 mg/L [IQR 221, 277.5]. An infectious inflammatory process was identified in 195 patients. Ferritin levels were relatively low in comparison with the CRP in each group, divided according to time from symptom onset until the procurement of blood tests. The discrepancy between high CRP and low ferritin suggests that these two acute phase response proteins utilize different pathways, resulting in a failure to increase ferritin concentrations in a documented state of hyperinflammation. A new entity of normoferremic inflammation accounts for a significant percentage of patients with acute bacterial infections, which enables bacteria to better survive the inflammation and serves as a new "inflammatory stamp".

Association between laboratory markers and Covid-19 disease severity and outcome: a retrospective cohort study in Saudi Arabia

Introduction

In Saudi Arabia, limited studies have evaluated factors including epidemiologic, clinical, and laboratory findings that are associated with COVID-19 disease. The aim of this paper was to identify laboratory parameters used in King Abdulaziz University Hospital which show an association with disease severity and patient outcome in the form of mortality.

Methods

Age, gender, medical history, and laboratory parameters were all retrospectively assessed concerning disease severity and disease outcome in a total of 111 COVID-19 patients at King Abdulaziz University Hospital between July 2020 and August 2020. Patients were categorized into mild disease if they did not require ward admission, moderate if they met the Ministry of Health criteria for isolation ward admition, and severe if they were admitted to the ICU.

Results

Age but not gender was associated with the disease severity X² (4, N = 110) = 27.2, p <0.001. Of all laboratory parameters on admission, only the levels of Albumin appeared to be significantly associated X² (2, N =70) = 6.6, p <0.05 with disease severity. Age but not gender was also significantly associated with disease outcome X² (2, N = 110) = 12.8, p < 0.01. Interestingly, RBC count also showed a significant relation with disease outcome X² (2, N = 71) = 6.1, p <0.05.

Discussion

This study provides more understanding of the laboratory characteristics in our part of the world to efficiently manage the disease.

Biomarkers to guide immunomodulatory treatment: where do we stand?

INTRODUCTION

This review summarizes current progress in the development of biomarkers to guide immunotherapy in oncology, rheumatology, and critical illness.

AREAS COVERED

An extensive literature search was performed about biomarkers classifying patients' immune responses to guide immunotherapy in oncology, rheumatology, and critical illness. Surface markers, such as programmed death-ligand 1 (PD-L1), genetic biomarkers, such as tumor mutation load, and circulating tumor DNA are biomarkers associated with the effectiveness of immunotherapy in oncology. Genomics, metabolomics, and proteomics play a crucial role in selecting the most suitable therapeutic options for rheumatologic patients. Phenotypes and endotypes are a promising approach to detect critically ill patients with hyper- or hypo-inflammation. Sepsis trials using biomarkers such as ferritin, lymphopenia, HLA-DR expression on monocytes and PD-L1 to guide immunotherapy have been already conducted or are currently ongoing. Immunotherapy in COVID-19 pneumonia, guided by C-reactive protein and soluble urokinase plasminogen activator receptor (suPAR) has improved patient outcomes globally. More research is needed into immunotherapy in other critical conditions.

EXPERT OPINION

Targeted immunotherapy has improved outcomes in oncology and rheumatology, paving the way for precision medicine in the critically ill. Transcriptomics will play a crucial role in detecting the most suitable candidates for immunomodulation.

COVID-19 mortality and risk factors in patients with cancer in Ecuador: A retrospective, non-randomized, controlled study

The 2019 coronavirus disease (COVID-19) pandemic has affected different human populations since March 2020 and challenged healthcare systems, especially in chronic non-communicable diseases such as cancer. The present study aimed to evaluate the mortality, risk factors, and symptoms of cancer patients and control subjects, diagnosed with COVID-19 and admitted to intensive care unit (ICU). This retrospective, observational, non-randomized, controlled study of patients admitted to ICU was conducted between March and August 2020 in an Ecuadorian oncology center. Patient information collected from electronic medical records included sociodemographic information, clinical history, symptoms, laboratory test results, COVID-19 treatment, and discharge status. For patients with neoplasia, diagnosis, type, and status of cancer, as well as antineoplastic treatment received over the past month was also recorded. Descriptive statistics and multiple logistic regression were used to analyze the data. Statistical analysis was performed with SPSS (version 22.0) and R (version 4.1.3). In total, 79 adult COVID-19 patients were studied (40 with cancer and 39 controls). The total mean time until COVID-19 symptoms onset was 6.2 ± 3.5 days (5.3 ± 3.2 days in the cancer group vs 7.2 ± 3.6 days in the control group; P = .016) but no difference was observed in reported symptoms. All patients received an antibiotic treatment, but only 70% of the cancer group had antivirals (P < .001). Cancer patients had lower hemoglobin levels than controls (10.7 ± 2.8 vs 13.3 ± 1.7 g/dL; P < .001). In terms of mortality, not statistically significance difference was reported between groups. The study showed that high ferritin (Absolute Odds Ratio of 3.9; 95% CI 1.1-14.6) and mechanical ventilation (Absolute Odds Ratio of 4.9; 95% CI 1.3-18.6) were independent COVID-19 mortality risk factors. COVID-19 infection did not represent an increased risk of mortality in cancer patients, but elevated ferritin levels and the need for mechanical ventilation were identified as mortality risk factors.

Evaluation of Thyroid Function Tests in Patients With COVID-19

Background SARS-CoV-2 infects cells via angiotensin-converting enzyme 2 (ACE2). ACE2 levels are high in the thyroid gland. Although the thyroid gland can be directly infected in COVID-19 patients, the hypothalamic-pituitary-thyroid axis is also affected. Therefore, changes in thyroid function occur in COVID-19 patients. This study aimed to examine the effect of thyroid function tests on the prognosis of COVID-19. Methodology A total of 146 patients who were diagnosed with COVID-19 and treated in the intensive care unit between August and November 2021 and who had no previous history of thyroid disease were included in the study. Demographic information, laboratory tests, and thyroid hormone levels during hospitalization and discharge patterns were evaluated. The patients were divided into two groups: group I included those who were discharged after recovery, and group II included those who did not respond to treatment and died. Results When the fT3 and fT4 levels of the patients were compared, the hormone levels decreased as the clinical severity of the disease increased. The amount of decrease in hormone levels was mostly seen in group II. In the recovered patient group, the amount of hormone decreased was less. The difference between fT3 and ft4 values between the groups was found to be statistically significant (P = 0.015 and P = 0.004). In addition, the difference between the groups' C-reactive protein (CRP), D-dimer, and ferritin values was statistically significant (P = 0.036, P = 0.022, and P < 0.000, respectively). There was no statistically significant difference between the groups in terms of demographic characteristics (P > 0.05). Conclusions Thyroid hormone changes were found to be an important prognostic parameter affecting disease severity and mortality in COVID-19 patients and can be used to predict mortality.

Association of Serum Ferritin With Severity of Disease in Real-Time Reverse Transcription-Polymerase Chain Reaction Negative COVID-19 Patients

BACKGROUND

Coronavirus disease 2019 (COVID-19) is still causing disastrous effects in various parts of the world through recurring waves. Real-time reverse transcription polymerase chain reaction (RT-PCR)-negative COVID-19 is particularly challenging as these patients are less likely to receive treatment and more likely to progress to severe disease. Thus, it is imperative to find markers that can predict the severity of disease at an early stage. The objective of the present study was to analyze the association of ferritin levels with severe disease in RT-PCR-negative COVID-19 patients.

METHODS

A prospective cross-sectional analytical study was conducted in adults with COVID-19 pneumonia with a negative RT-PCR test from October 2020 to September 2021. Hematologic, biochemical, and inflammatory parameters were investigated within 24 h of hospitalization. Demographic, clinical, and laboratory findings were compared between patients with and without severe disease.

RESULTS

A total of 220 patients were included. The mean age of the study participants was 47.3 ± 14.2 years, and 55.5% (n=122) were male. C-reactive protein, D-dimer, and ferritin levels were significantly higher in patients with severe disease (p<0.01). Receiver operating characteristic curve analyses were performed, and ferritin was found as significant predictor of severe disease (area under the curve=0.642, p<0.001).

CONCLUSION

Early analysis of ferritin can predict the severity of disease in COVID-19 patients, irrespective of the RT-PCR status.

Ovarian Cancer Biomarkers in the COVID-19 Era

Ovarian Cancer (OC) diagnosis is entrusted to CA125 and HE4. Since the latter has been found increased in COVID-19 patients, in this study, we aimed to evaluate the influence of SARS-CoV-2 infection on OC biomarkers. HE4 values above the cut-off were observed in 65% of OC patients and in 48% of SARS-CoV-2-positive patients (not oncologic patients), whereas CA125 values above the cut-off were observed in 71% of OC patients and in 11% of SARS-CoV-2 patients. Hence, by dividing the HE4 levels into quartiles, we can state that altered levels of HE4 in COVID-19 patients were mostly detectable in quartile I (151-300 pmol/L), while altered levels in OC patients were mostly clustered in quartile III (>600, pmol/L). In light of these observations, in order to better discriminate women with ovarian cancer versus those with COVID-19, we established a possible HE4 cut-off of 328 pmol/L by means of a ROC curve. These results demonstrate that the reliability of HE4 as a biomarker in ovarian cancer remains unchanged, despite COVID-19 interference; moreover, it is important for a proper diagnosis that whether the patient has a recent history of SARS-CoV-2 infection is determined.

Association of serum ferritin with severity and clinical outcome in COVID-19 patients: An observational study in a tertiary healthcare facility

Background

Ferritin, an intracellular protein, has a pivotal role in immune dysregulation. Hyperferritinemia has been associated with higher disease severity and adverse clinical outcomes in COVID-19, including mortality. We aimed to study the association of serum ferritin levels with disease severity and clinical outcomes and its severity prediction potential in COVID-19 patients.

Methods

This retrospective study included 870 adult patients with symptomatic COVID-19 infection hospitalized between July 1, 2020 to December 21, 2020. All the patients had a positive polymerase chain reaction test result of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Results

The median age was 55 (IQR:40, 65) years with a male predominance [66.32% (n = 577)], among 870 COVID-19. Of these, 413 (47.47%) had mild COVID-19, and 457 (52.53%) had moderate plus severe COVID-19 disease. Median ferritin levels were significantly high in moderate to severe COVID-19 infection compared to mild [545.8 (326.0, 1046.0) vs 97.3 (52.65-155.5) (p = 0.001)], and in patients who developed a complication compared to without complications [380 (177.05, 863.15) vs 290 (110.9, 635) (p = 0.002). A slight elevation in median ferritin levels was observed in patients who had an ICU stay than non-ICU [326 (129.8, 655) vs 309 (119.1, 684) (p = 0.872)]. The cut-off for ferritin was identified at >287.4 ng/ml for mild versus moderate plus severe COVID-19 infections.

Conclusion

Moderate to severe COVID-19 patients have elevated ferritin levels. Patients with more than 287.4 ng/ml ferritin value would have greater chances of developing moderate to severe COVID-19 infections.

COVID-19 Biomarkers at the Crossroad between Patient Stratification and Targeted Therapy: The Role of Validated and Proposed Parameters

Clinical knowledge about SARS-CoV-2 infection mechanisms and COVID-19 pathophysiology have enormously increased during the pandemic. Nevertheless, because of the great heterogeneity of disease manifestations, a precise patient stratification at admission is still difficult, thus rendering a rational allocation of limited medical resources as well as a tailored therapeutic approach challenging. To date, many hematologic biomarkers have been validated to support the early triage of SARS-CoV-2-positive patients and to monitor their disease progression. Among them, some indices have proven to be not only predictive parameters, but also direct or indirect pharmacological targets, thus allowing for a more tailored approach to single-patient symptoms, especially in those with severe progressive disease. While many blood test-derived parameters quickly entered routine clinical practice, other circulating biomarkers have been proposed by several researchers who have investigated their reliability in specific patient cohorts. Despite their usefulness in specific contexts as well as their potential interest as therapeutic targets, such experimental markers have not been implemented in routine clinical practice, mainly due to their higher costs and low availability in general hospital settings. This narrative review will present an overview of the most commonly adopted biomarkers in clinical practice and of the most promising ones emerging from specific population studies. Considering that each of the validated markers reflects a specific aspect of COVID-19 evolution, embedding new highly informative markers into routine clinical testing could help not only in early patient stratification, but also in guiding a timely and tailored method of therapeutic intervention.

Ultradiluted SARS-CoV-2 Spike Protein mitigates hyperinflammation in lung via ferritin and MMP-9 regulation in BALB/c mice

AIM

This study investigated the prophylactic and therapeutic role of ultradiluted preparation of the Delta variant of SARS-CoV-2 recombinant spike (S) protein during S antigen-induced inflammatory process of disease progression along with the probable mechanism of action.

MAIN METHODS

Ultradiluted S protein (UDSP) was prepared and administered orally to adult BALB/c mice before and after administration of S antigen intranasally. After an observation period of 72 h, animals were sacrificed and expression level of ferritin was assayed through ELISA. The genetic expressions of cytokines, IL-6, IL-10, IL-1β, TNFα, IL-17, MMP-9, TIMP-1, ferritin light and heavy chains, and mitochondrial ferritin from lung tissues were investigated through RT-PCR. Formalin-fixed lung tissue sections were stained with hematoxylin and eosin to observe the degree of pathological changes. The activity of MMP-9 in lung tissues was investigated through gelatin zymography and immunofluorescence of MMP-9 in lung tissue sections was performed to revalidate the finding from gelatin zymography. Systems biology approach was used to elucidate a probable pathway where UDSP attenuated the inflammation through the regulation of pro- and anti-inflammatory cytokines.

KEY FINDINGS

UDSP attenuated the S antigen-induced hyperinflammation in the lung by regulating pro- and anti-inflammatory cytokines, calming cytokine storm, reducing ferritin level both in transcriptional and translational levels, and restoring critical ratio of MMP-9: TIMP-1.

SIGNIFICANCE

Our findings suggest a probable pathway by which UDSP might have attenuated inflammation through the regulation of cytokines, receptors, and other molecules. This proclaims UDSP as a promising antiviral agent in the treatment of COVID-19-induced immunopathogenesis.

Bidirectional Relationship between Glycemic Control and COVID-19 and Perspectives of Islet Organoid Models of SARS-CoV-2 Infection

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to morbidity and mortality, with several clinical manifestations, and has caused a widespread pandemic. It has been found that type 2 diabetes is a risk factor for severe coronavirus disease 2019 (COVID-19) illness. Moreover, accumulating evidence has shown that SARS-CoV-2 infection can increase the risk of hyperglycemia and diabetes, though the underlying mechanism remains unclear because of a lack of authentic disease models to recapitulate the abnormalities involved in the development, regeneration, and function of human pancreatic islets under SARS-CoV-2 infection. Stem-cell-derived islet organoids have been valued as a model to study islets’ development and function, and thus provide a promising model for unraveling the mechanisms underlying the onset of diabetes under SARS-CoV-2 infection. This review summarized the latest results from clinical and basic research on SARS-CoV-2-induced pancreatic islet damage and impaired glycemic control. Furthermore, we discuss the potential and perspectives of using human ES/iPS cell-derived islet organoids to unravel the bidirectional relationship between glycemic control and SARS-CoV-2 infection.

Pneumothorax in hospitalized COVID-19 patients with severe respiratory failure: Risk factors and outcome

PNX was described as an uncommon complication in COVID-19 patients but clinical risk predictors and the potential role in patient's outcome are still unclear. We assessed prevalence, risk predictors and mortality of PNX in hospitalized COVID- 19 with severe respiratory failure performing a retrospective observational analysis of 184 patients admitted to our COVID-19 Respiratory Unit in Vercelli from October 2020 to March 2021. We compared patients with and without PNX reporting prevalence, clinical and radiological features, comorbidities, and outcomes. Prevalence of PNX was 8.1% and mortality was >86% (13/15) significantly higher than in patients without PNX (56/169) (P < 0.001). PNX was more likely to occur in patients with a history of cognitive decline (HR: 31.18) who received non-invasive ventilation (NIV) (p < 0.0071) and with low P/F ratio (HR: 0.99, p = 0.004). Blood chemistry in the PNX subgroup compared to patients without PNX showed a significant increase in LDH (420 U/L vs 345 U/L, respectively p = 0.003), ferritin (1111 mg/dl vs 660 mg/dl, respectively p = 0.006) and decreased lymphocytes (HR: 4.440, p = 0.004). PNX may be associated with a worse prognosis in terms of mortality in COVID patients. Possible mechanisms may include the hyperinflammatory status associated with critical illness, the use of NIV, the severity of respiratory failure and cognitive impairment. We suggest, in selected patients showing low P/F ratio, cognitive impairment and metabolic cytokine storm, an early treatment of systemic inflammation in association with high-flow oxygen therapy as a safer alternative to NIV in order to avoid fatalities connected with PNX.

Effect of ferritin, INR, and D-dimer immunological parameters levels as predictors of COVID-19 mortality: A strong prediction with the decision trees

Background and objective

A hyperinflammatory environment is thought to be the distinctive characteristic of COVID-19 infection and an important mediator of morbidity. This study aimed to determine the effect of other immunological parameter levels, especially ferritin, as a predictor of COVID-19 mortality via decision-trees analysis.

Material and method

This is a retrospective study evaluating a total of 2568 patients who died (n = 232) and recovered (n = 2336) from COVID-19 in August and December 2021. Immunological laboratory data were compared between two groups that died and recovered from patients with COVID-19. In addition, decision trees from machine learning models were used to evaluate the performance of immunological parameters in the mortality of the COVID-19 disease.

Results

Non-surviving from COVID-19 had 1.75 times higher ferritin, 10.7 times higher CRP, 2.4 times higher D-dimer, 1.14 times higher international-normalized-ratio (INR), 1.1 times higher Fibrinogen, 22.9 times higher procalcitonin, 3.35 times higher troponin, 2.77 mm/h times higher erythrocyte-sedimentation-rate (ESR), 1.13sec times longer prothrombin time (PT) when compared surviving patients. In addition, our interpretable decision tree, which was constructed with only the cut-off values of ferritin, INR, and D-dimer, correctly predicted 99.7% of surviving patients and 92.7% of non-surviving patients.

Conclusions

This study perfectly predicted the mortality of COVID-19 with our interpretable decision tree constructed with INR and D-dimer, especially ferritin. For this reason, we think that it may be important to include ferritin, INR, and D-dimer parameters and their cut-off values in the scoring systems to be planned for COVID-19 mortality.

COVID-19 compromises iron homeostasis: Transferrin as a target of investigation

IMPORTANCE

Since the beginning of the COVID-19 pandemic, numerous metabolic alterations have been observed in individuals with this disease. It is known that SARS-CoV-2 can mimic the action of hepcidin, altering intracellular iron metabolism, but gaps remain in the understanding of possible outcomes in other pathways involved in the iron cycle.

OBJECTIVE

To profile iron, ferritin and hepcidin levels and transferrin receptor gene expression in patients diagnosed with COVID-19 between June 2020 and September 2020.

DESIGN, SETTING AND PARTICIPANTS

Cross-sectional study that evaluated iron metabolism markers in 427 participants, 218 with COVID-19 and 209 without the disease.

EXPOSURES

The primary exposure was positive diagnose to COVID-19 in general population of Santo André and São Bernardo cities. The positive and negative diagnose were determinate through RT-qPCR.

MAIN OUTCOMES AND MEASURES

Devido a evidências de alterações do ciclo do ferro em pacientes diagnosticados com COVID-19 e devido a corregulação entre hepcidina e receptor de transferrina, uma análise da expressão gênica deste último, poderia trazer insights sobre o estado de ferro celular. A hipótese foi confirmada, mostrando aumento da expressão de receptor de transferrina concomitante com redução do nível de hepcidina circulante.

RESULTS

Serum iron presented lower values in individuals diagnosed with COVID-19, whereas serum ferritin presented much higher values in infected patients. Elderly subjects had lower serum iron levels and higher ferritin levels, and men with COVID-19 had higher ferritin values than women. Serum hepcidin was lower in the COVID-19 patient group and transferrin receptor gene expression was higher in the infected patient group compared to controls.

CONCLUSIONS AND RELEVANCE

COVID-19 causes changes in several iron cycle pathways, with iron and ferritin levels being markers that reflect the state and evolution of infection, as well as the prognosis of the disease. The increased expression of the transferrin receptor gene suggests increased iron internalization and the mimicry of hepcidin action by SARS-CoV-2, reduces iron export via ferroportin, which would explain the low circulating levels of iron by intracellular trapping.

The relationship between diaphragm thickness and the severity of the disease in pregnant patients with Covid-19

OBJECTIVE

We aimed to investigate whether there is a relationship between diaphragm thickness and disease severity in Covid-19 pregnant subgroups.

MATERIAL AND METHODS

In this prospective study 100 pregnant patients were enrolled. Thickness of the diaphragm muscle at end-expiration was measured using B-Mode US. Hemoglobin,WBC, NLR, procalcitonin and LDH levels were measured.

RESULTS

There was a statistically significant difference between the groups in terms of diaphragm thickness, and the diaphragm thickness was thinner in the severe disease group (p < 0.001). There was no statistically significant difference between the groups with mild to moderate disease severity (p = 0.708).

CONCLUSION

Covid-19 patients who developed serious infection has thinner diaphragms than those who did not. Low diaphragm muscle thickness at the outset of Covid-19 disease, may predispose to poor clinical outcomes. Diaphragmatic ultrasound may be a promising tool to evaluate the risk of Covid-19 disease severity.

Association between iron metabolism and SARS-COV-2 infection, determined by ferritin, hephaestin and hypoxia-induced factor-1 alpha levels in COVID-19 patients

BACKGROUND

Due to the growing evidence of the importance of iron status in immune responses, the biomarkers of iron metabolism are of interest in novel Coronavirus Disease 2019 (COVID-19). The present prospective study was carried out to compare iron status indicated by levels of ferritin with the levels of two novel biomarkers related to iron homeostasis, hephaestin and hypoxia-inducible factors-1 (HIF-1α) in the serum of patients with COVID-19 in comparison with a control group.

METHODS AND RESULTS

Blood samples from 34 COVID-19 patients and from 43 healthy volunteers were collected and the levels of HEPH and HIF-1α were measured by ELISA and compared with levels of serum ferritin. COVID-19 patients had higher serum levels of ferritin than those levels in control group (P < 0.0001). Conversely levels of HIF-1α and HEPH in the COVID-19 group were significantly lower than those of control group (P < 0.0001 for both). An inverse correlation between hephaestin and ferritin as well as between HIF-1α and ferritin was found among all subjects (P < 0.0001), and among COVID-19 patients, but not to statistical significance.

CONCLUSION

Levels of hephaestin and HIF-1α were found to be inversely related levels of ferritin across all participants in the study, and to our knowledge this is the first report of hephaestin and HIF-1α as potential markers of iron status. Further studies are needed to corroborate the findings, utilizing a broader range of markers to monitor inflammatory as well as iron status.

Association between serum ferritin level and decreased diffusion capacity 3 months after the onset of COVID-19 pneumonia

BACKGROUND

Coronavirus disease 2019 (COVID-19) pneumonia can have prolonged sequelae and lead to respiratory dysfunction, mainly because of impaired diffusion capacity for carbon monoxide (DLCO). The clinical factors associated with DLCO impairment, including blood biochemistry test parameters, remain unclear.

METHODS

Patients with COVID-19 pneumonia who underwent inpatient treatment between April 2020 and August 2021 were included in this study. A pulmonary function test was performed 3 months after onset, and the sequelae symptoms were investigated. Clinical factors, including blood test parameters and abnormal chest shadows on computed tomography, of COVID-19 pneumonia associated with DLCO impairment were investigated.

RESULTS

In total, 54 recovered patients participated in this study. Twenty-six patients (48%) and 12 patients (22%) had sequelae symptoms 2 and 3 months after, respectively. The main sequelae symptoms at 3 months were dyspnea and general malaise. Pulmonary function tests showed that 13 patients (24%) had both DLCO <80% predicted value (pred) and DLCO/alveolar volume (VA) <80% pred, and appeared to have DLCO impairment not attributable to an abnormal lung volume. Clinical factors associated with impaired DLCO were investigated in multivariable regression analysis. Ferritin level of >686.5 ng/mL (odds ratio: 11.08, 95% confidence interval [CI]: 1.84-66.59; p = 0.009) was most strongly associated with DLCO impairment.

CONCLUSIONS

Decreased DLCO was the most common respiratory function impairment, and ferritin level was a significantly associated clinical factor. Serum ferritin level could be used as a predictor of DLCO impairment in cases of COVID-19 pneumonia.

Parameters to Predict the Outcome of Severe and Critical COVID-19 Patients when Admitted to the Hospital

Manifestations of COVID-19 are diverse and range from asymptomatic to severe, critical illness and death. Cases requiring hospital care (in severe and critical illnesses) are associated with comorbidities and hyperactivation of the immune system. Therefore, in this exploratory observational study, we analyzed which parameters are associated with mortality. We evaluated: demographic characteristics (age, sex and comorbidities), laboratory data (albumin, leukocytes, lymphocytes, platelets, ferritin), days of hospital stay, interleukins (IL-2, IL-6, IL-7, IL-10, IL-17) and sP-selectin in 40 Mexican patients admitted to medical emergencies with a confirmed diagnosis of COVID-19, a complete clinical record, and who signed the informed consent. Twenty severe (they required intermediate care with non-invasive ventilation) and twenty critically ill patients (they required mechanical ventilation) were classified, and these were subsequently compared with healthy and recovered subjects. A significant difference was found between the hospitalized groups in the parameters of age, ferritin, days of hospital stay and death with p values = 0.0145, p = 0.0441, p = 0.0001 and p = 0.0001, respectively. In the determination of cytokines and P-selectin, a significant difference was found between the following groups: recovered patients and healthy volunteers compared with hospitalized patients in severe and critical condition. Importantly, IL-7 remained elevated one year later in recovered patients. Taken together, these values determined at the time of hospital admission could be useful to monitor patients closely and evaluate in-hospital progress, hospital discharge, and out-of-hospital progress.

Immune Response to Vaccination against COVID-19 at Different Second-Dose Intervals and Their Associations with Metabolic Parameters

Obesity and diabetes are associated with severe outcomes of coronavirus disease (COVID-19). Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been proven protective against infection and severe COVID-19. However, the immune response of metabolically burdened individuals to the vaccines remains unclear. Thus, we aimed to assess whether the metabolic status of individuals affects their humoral immune responses to the vaccination. Moreover, we evaluated whether the interval between the first two doses influenced antibody concentration. Sixty-seven individuals (21 males, 46 females) were vaccinated with the BNT162b2 mRNA COVID-19 vaccine. Fifty-four individuals were vaccinated with the second dose after 3 weeks and 13 after 5 weeks. We measured the antibody titers in all participants during the 19-week follow-up period. Patients diagnosed with COVID-19 were excluded. In the 5-week interval group, a significantly higher level of maximal antibody titers was observed. However, there were no differences in antibody concentrations after 19 weeks and no significant correlation between cardiometabolic factors and humoral response. The elongation of second-dose timing to 5 weeks leads to a higher acute antibody response but does not change long-term levels of antibody titers. Moreover, dysregulation of metabolic parameters does not lead to a diminished immune response to vaccination.

Race and Remdesivir: Examination of Clinical Outcomes in a Racially and Ethnically Diverse Cohort in New York City

Objective

To compare clinical characteristics and examine in-hospital length of stay (LOS) differences for COVID-19 patients who received remdesivir, by race or ethnicity.

Design

Retrospective descriptive analysis comparing cumulative LOS as a proxy of recovery time.

Setting

A large academic medical center serving a minoritized community in Northern Manhattan, New York City.

Participants

Inpatients (N=1024) who received remdesivir from March 30, 2020-April 20, 2021.

Methods

We conducted descriptive analyses among patients who received remdesivir. Patients were described by proxies of social determinants of health (SDOH): race and ethnicity, residence, insurance coverage, and clinical characteristics. We calculated median hospital LOS as the cumulative incidence of hospitalized patients who were discharged alive, and tested differences between groups by using the Gray test. Patients who died or were discharged to hospice were censored at 29 days.

Main Outcome Measures

The primary outcome was hospital LOS. The secondary outcome was in-hospital mortality.

Results

Median LOS was 11.9 days (95% CI, 10.8-13.2) overall, with Black patients having the shortest (10.0 days, 95% CI, 8.0-13.2) and Asian patients having the longest (16.2 days, 95% CI, 8.3-27.2) LOS. A total of 214 patients (21%) died or were discharged to hospice, ranging from 16.5% to 23.7% of patients who identified as Black and Other (multiracial, biracial, declined), respectively.

Conclusions

COVID-19 has disproportionately burdened communities of color. We observed no difference in median LOS between racial or ethnic groups, which supports the notion that the heterogeneous effect of remdesivir in the literature may be explained in part by underrecruitment or participation of Black, Hispanic, and Asian patients in clinical trials.

COVID-19 Infections and Inflammatory Markers in Patients Hospitalized During the First Year of the Pandemic

BACKGROUND

The clinical presentations in patients with SARS-CoV-2 (COVID-19) infections range from asymptomatic upper respiratory infections to acute respiratory failure with bilateral pulmonary infiltrates requiring mechanical ventilation. Clinicians often measured inflammatory markers in hospitalized patients to characterize the severity of the infection. Multiple studies published in 2020 reported information on the frequency of elevated inflammatory markers in hospitalized patients in various categories of disease severity.

METHODS

The PubMed database was searched using the terms "Inflammatory markers in COVID-19 patients" and "Clinical features of patients infected with COVID-19." Thirty-three publications were analyzed in detail to determine which inflammatory markers were increased and the frequency of these increases in various clinical classifications, including patients requiring hospitalization, patients with pneumonia, patients with severe infection, patients requiring intensive care unit admission, and patients who died.

RESULTS

C-reactive protein (CRP) was the most frequently elevated inflammatory marker in all categories. Ferritin, D-dimer, and erythrocyte sedimentation rate levels were also frequently elevated. In general, frequencies were higher in patients with more severe infections. For example, 24 out of 24 patients who died had an elevated CRP level.

CONCLUSION

This review provides concrete information about the frequency of various inflammatory markers in patients with COVID-19 infection who required hospitalization. It also provides us some insight into the approach clinicians took in the early phase of this pandemic in their efforts to characterize these patients and perhaps understand the disease process better. However, these results might suggest that clinicians and laboratory directors should develop protocols to optimize laboratory testing.

Extracting relevant predictive variables for COVID-19 severity prognosis: An exhaustive comparison of feature selection techniques

With the COVID-19 pandemic having caused unprecedented numbers of infections and deaths, large research efforts have been undertaken to increase our understanding of the disease and the factors which determine diverse clinical evolutions. Here we focused on a fully data-driven exploration regarding which factors (clinical or otherwise) were most informative for SARS-CoV-2 pneumonia severity prediction via machine learning (ML). In particular, feature selection techniques (FS), designed to reduce the dimensionality of data, allowed us to characterize which of our variables were the most useful for ML prognosis. We conducted a multi-centre clinical study, enrolling n = 1548 patients hospitalized due to SARS-CoV-2 pneumonia: where 792, 238, and 598 patients experienced low, medium and high-severity evolutions, respectively. Up to 106 patient-specific clinical variables were collected at admission, although 14 of them had to be discarded for containing ⩾60% missing values. Alongside 7 socioeconomic attributes and 32 exposures to air pollution (chronic and acute), these became d = 148 features after variable encoding. We addressed this ordinal classification problem both as a ML classification and regression task. Two imputation techniques for missing data were explored, along with a total of 166 unique FS algorithm configurations: 46 filters, 100 wrappers and 20 embeddeds. Of these, 21 setups achieved satisfactory bootstrap stability (⩾0.70) with reasonable computation times: 16 filters, 2 wrappers, and 3 embeddeds. The subsets of features selected by each technique showed modest Jaccard similarities across them. However, they consistently pointed out the importance of certain explanatory variables. Namely: patient's C-reactive protein (CRP), pneumonia severity index (PSI), respiratory rate (RR) and oxygen levels -saturation Sp O2, quotients Sp O2/RR and arterial Sat O2/Fi O2-, the neutrophil-to-lymphocyte ratio (NLR) -to certain extent, also neutrophil and lymphocyte counts separately-, lactate dehydrogenase (LDH), and procalcitonin (PCT) levels in blood. A remarkable agreement has been found a posteriori between our strategy and independent clinical research works investigating risk factors for COVID-19 severity. Hence, these findings stress the suitability of this type of fully data-driven approaches for knowledge extraction, as a complementary to clinical perspectives.