Invalidity of JRS atypical pneumonia prediction score in Omicron variant of COVID-19 pneumonia.

BACKGROUND: We evaluated whether the Japanese Respiratory Society (JRS) atypical pneumonia prediction score can be adapted for the diagnosis of COVID-19 pneumonia due to Omicron BA.1, BA.2, and BA.5 subvariants. METHODS: We enrolled a total of 547 patients with community-acquired COVID-19 pneumonia. Of the COVID-19 pneumonia patients, 198 cases were the Omicron BA.1 subvariant, 127 cases were the Omicron BA.2 subvariant, and 222 cases were the Omicron BA.5 subvariant. Patients with extremely severe pneumonia were excluded and finally 524 patients were analyzed. RESULTS: Rates of conformity for the six predictors were identical among the three Omicron groups, and high rates of conformity were observed in the following predictors: adventitious sounds; etiological agent; and a peripheral WBC count. The sensitivities of the diagnosis of atypical pneumonia in patients with COVID-19 pneumonia based on four or more predictors were 49.0% in the BA.1 subvariant group, 58.1% in the BA.2 subvariant group, and 51.0% in the BA.5 subvariant group. The diagnostic sensitivities for Omicron BA.1, BA.2, and BA.5 subvariant groups were 96.6%, 100%, and 96.4% for non-elderly (aged <60 years) patients and 28.4%, 29.7%, and 34.2% for elderly (aged ≥60 years) patients, respectively. CONCLUSIONS: In Omicron variant of COVID-19, the JRS atypical pneumonia prediction score is a useful tool for distinguishing between COVID-19 pneumonia and bacterial pneumonia only in patients aged <60 years.

Evaluation of characteristics and prognosis of COVID-19 patients requiring invasive mechanical ventilation during dominance of nonvariant, alpha, delta, and omicron variants in tertiary hospitals of Japan.

BACKGROUND: In November 2021, the B.1.1.529 (omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was detected in South Africa and subsequently rapidly spread around the world. Despite the reduced severity of the omicron variants, many patients become severely ill after infection and undergo invasive mechanical ventilation, but there are few reports on their background and prognosis throughout all variant periods. This study aimed to evaluate risk factors affecting patients requiring invasive mechanical ventilation with each variant of COVID-19 pandemic in Japan from nonvariants to omicron variants. METHOD: This retrospective observational study was conducted at the Department of Emergency and Critical Care Medicine, Kansai Medical University Hospital and Kansai Medical University Medical Center, Osaka, Japan, from March 2020 to March 2023. Eligible patients were those who underwent invasive ventilation for COVID-19 pneumonia. We set the primary endpoint as in-hospital mortality. Multivariable logistic regression analysis adjusted for clinically important variables was performed to evaluate the clinical outcomes. RESULTS: We included 377 patients: 118 in the Nonvariant group, 154 in the Alpha group, 42 in the Delta group, and 63 patients in the Omicron group. Mortality rates for each group were 23.7% for the Nonvariant group, 12.3% for the Alpha group, 7.1% for the Delta group, and 30.5% for the Omicron group. Patient age was significantly associated with increased mortality (adjusted odds ratio [AOR]: 1.097; 95% confidence interval [CI]: 1.057-0.138, P < 0.001). Immunodeficiency (AOR: 3.388, 95% CI: 1.377-8.333, P = 0.008), initial SOFA score (AOR: 1.190, 95% CI: 1.056-1.341, P = 0.004), dialysis prior to COVID-19 (AOR: 3.695, 95% CI: 1.117-11.663, P = 0.026), and smoking history (AOR: 2.548, 95% CI: 1.153-5.628, P = 0.021) were significantly associated with increased mortality. Differences in variants were not significant factors associated with high mortality. CONCLUSION: We compared the background and prognosis of patients with COVID-19 pneumonia requiring invasive mechanical ventilation between SARS-CoV-2 variants. In these patients, differences in variants did not affect prognosis. Hospital mortality in critically ill COVID-19 patients was significantly higher in the older patients with bacterial coinfection, or patients with immunodeficiency, COPD, and chronic renal failure on dialysis.

Functional decline at 1 year in hospitalized elderly pneumonia with SARS-CoV-2 Omicron variant: Comparison with the ancestral strain and Alpha variant.

In the SARS-CoV-2 Omicron period, the pattern of pneumonia changed from primarily viral pneumonia to pneumonia mixed with bacteria in the elderly. We investigated functional outcomes at 1 year after hospital discharge in patients with primary Omicron pneumonia and pneumonia mixed with bacteria, mainly aspiration pneumonia. Functional decline rates calculated using the Barthel Index at 1 year after hospital discharge were significantly higher in the pneumonia mixed with bacteria group than the primary viral pneumonia group (42.6% vs. 20.5%, p < 0.0001). It is necessary to consider early rehabilitation and treatment in elderly patients even when the predominant strain is the Omicron variant.

Is the JRS atypical pneumonia prediction score useful in detecting COVID-19 pneumonia under nursing or healthcare settings?

BACKGROUND: SARS-CoV-2 causes frequent outbreaks in elderly care facilities that meet the criteria for nursing and healthcare-associated pneumonia (NHCAP). We evaluated whether the Japanese Respiratory Society (JRS) atypical pneumonia prediction score could be adapted to the diagnosis of nursing and healthcare acquired COVID-19 (NHA-COVID-19) with pneumonia. METHODS: We analyzed 516 pneumonia patients with NHA-COVID-19 and compared them with 1505 pneumonia patients with community-associated COVID-19 (CA-COVID-19). NHA-COVID-19 patients were divided into six groups; 80 cases had the ancestral strain, 76 cases had the Alfa variant, 30 cases had the Delta variant, 120 cases had the Omicron subvariant BA.1, 53 cases had the Omicron subvariant BA.2, and 157 cases had the Omicron subvariant BA.5. RESULTS: The sensitivities of the diagnosis of atypical pneumonia in patients with NHA-COVID-19 based on four or more predictors were 22.8 % in the ancestral strain group, 32.0 % in the Alfa variant group, 34.5 % in the Delta variant group, 23.1 % in the BA.1 subvariant group, 32.7 % in the BA.2 subvariant group, and 30.4 % in the BA.5 subvariant group. The diagnostic sensitivity for the presumptive diagnosis of atypical pneumonia was significantly lower for NHA-COVID-19 than for CA-COVID-19 (28.2 % vs 64.1 %, p < 0.0001). CONCLUSIONS: Our present study demonstrated that the JRS atypical pneumonia prediction score is not a useful tool in elderly patients even if there is a lot of atypical pneumonia in the NHCAP group. The caution is necessary that JRS atypical pneumonia prediction score was not fully applied to prediction for NHA-COVID-19 pneumonia.

Nursing and healthcare-associated pneumonia due to SARS-CoV-2 Omicron variant.

BACKGROUND: There were many differences in the clinical characteristics between nursing and healthcare-associated pneumonia (NHCAP) and community-acquired pneumonia (CAP) due to the SARS-CoV-2 ancestral strain, Alpha variant and Delta variant. With the replacement of the Delta variant by the Omicron variant, the Omicron variant showed decreased infectivity to lung and was less pathogenic. We investigated the clinical differences between NHCAP and CAP due to the Omicron variant. METHODS: We analyzed 516 NHCAP and 547 CAP patients with COVID-19 pneumonia. Of 516 patients with COVID-19 NHCAP, 330 cases were the Omicron variant (120 cases were BA.1, 53 cases were BA.2, and 157 cases were BA.5 subvariants) and 186 cases were non-Omicron variants. RESULTS: The median age, frequency of comorbid illness, rates of intensive care unit (ICU) stay, and mortality rate were significantly higher in Omicron patients with NHCAP than in those with CAP. Rates of ICU stay and in-hospital mortality were significantly higher in NHCAP patients with non-Omicron variants compared with those in the Omicron variant group. No clinical differences were observed in patients with NHCAP among the Omicron BA.1, BA.2, and BA.5 subvariant groups. CONCLUSIONS: The present study supported that the NHCAP category is necessary not only for bacterial pneumonia but also viral pneumonia. It is necessary to consider prevention and treatment strategies depending on the presence or absence of applicable criteria for NHCAP.

Treatment strategy for severe trauma patients requiring aortic occlusion for impending cardiopulmonary arrest in the hybrid emergency room.

Aim: Computed tomography (CT) is useful in trauma care. Severely ill trauma patients may not tolerate whole-body CT even without patient transfer. This study examined clinical flow of severe trauma patients requiring aortic occlusion (AO) such as resuscitative thoracotomy or REBOA in the hybrid emergency room (ER) and investigated patient clinical courses prioritizing CT first versus resuscitation including AO first. Methods: This retrospective, single-center observational study included consecutive trauma patients visiting our ER between May 2016 and February 2023. Patients were divided into the CT first group (whole-body CT preceded AO) and AO first group (AO preceded whole-body CT) and into two subgroups: AO after CT (AO/interventions for hemorrhage performed just after CT in the CT first group), and CT after AO (CT or damage control surgery performed after AO in the AO first group). We investigated 28-day survival rates. Results: Survival probability by TRISS method was 49% (range: 3.3-94) in the CT first group (n = 6) and 20% (range: 0.7-45) in the AO first group (n = 7). Actual 28-day survival rates were 50% and 57%, respectively. Survival rates of the AO after CT subgroup (CT first group) were 75% (3/4) and 0% (0/2), respectively, and those of the CT after AO subgroup (AO first group) were 25% (1/4) and 100% (3/3), respectively. Conclusion: In severe trauma patients with low predicted probability of survival treated in the hybrid ER, survival rates might be better if resuscitation including AO is performed before CT and if damage control surgery is performed first before CT.

Comparison of pneumonia severity scores for COVID-19 patients with the Omicron variant.

INTRODUCTION: We demonstrated that there was a significant relationship between the severity measured using the A-DROP scoring system and the mortality rate in patients with COVID-19 community-acquired pneumonia (CAP) in the ancestral strain, Alpha variant, and Delta variant. We investigated the usefulness of the A-DROP scoring system in SARS-CoV-2 Omicron variant CAP and compared it with severity scores, the Pneumonia Severity Index (PSI) and CURB-65 score. METHODS: We analyzed a total of 547 patients with COVID-19 CAP Omicron variant; 198 cases were the BA.1 subvariant, 127 cases were the BA.2 subvariant, and 222 cases were the BA.5 subvariant, respectively. RESULTS: The mortality rates in patients with COVID-19 CAP among the three Omicron subvariants were identical in each pneumonia severity group. The mortality rate in patients with the Omicron variant was 0 % in patients classified with mild disease, 0.6 % in those with moderate disease, 10.4 % in those with severe disease, and 34.8 % in those with extremely severe disease. The mortality rate in patients with COVID-19 CAP increased depending on the severity classified according to the A-DROP system in each of the Omicron subvariants (Cochran-Armitage trend test; p < 0.001). The values of the area under the curve in Receiver Operating Characteristic analysis for prediction of 30-day mortality was 0.881, 0.879, and 0.863 for A-DROP, PSI, and CURB-65, respectively. There were no significant differences in the predictive ability of each pneumonia severity score. CONCLUSIONS: Our results demonstrated that the A-DROP scoring system is useful for predicting mortality in patients with COVID-19 CAP.

Clinical experience of treatment of immunocompromised individuals with persistent SARS-CoV-2 infection based on drug resistance mutations determined by genomic analysis: a descriptive study.

BACKGROUND: The efficacy of antiviral drugs that neutralize antibody drugs and fight against SARS-COV-2 is reported to be attenuated by genetic mutations of the virus in vitro. When B-cell immunocompromised patients are infected with SARS-COV-2, the infection can be prolonged, and genetic mutations can occur during the course of treatment. Therefore, for refractory patients with persistent COVID-19 infection, genomic analysis was performed to obtain data on drug resistance mutations as a reference to determine which antiviral drugs and antibody therapies might be effective in their treatment. METHODS: This was a descriptive analysis with no controls. Patients were diagnosed as having COVID-19, examined, and treated in the Kansai Medical University General Medical Center between January 2022 and January 2023. The subjects of the study were B-cell immunocompromised patients in whom genome analysis of SARS-CoV-2 was performed. RESULTS: During the study period, 984 patients with COVID-19 were treated at our hospital. Of those, 17 refractory cases underwent genomic analysis. All 17 patients had factors related to immunodeficiency, such as malignant lymphoma or post-organ transplantation. Eleven patients started initial treatment for COVID-19 at our hospital, developed persistent infection, and underwent genomic analysis. Six patients who were initially treated for COVID-19 at other hospitals became persistently infected and were transferred to our hospital. Before COVID-19 treatment, genomic analysis showed no intrahost mutations in the NSP5, the NSP12, and the RBD regions. After COVID-19 treatment, mutations in these regions were found in 12 of 17 cases (71%). Sixteen patients survived the quarantine, but one died of sepsis. CONCLUSIONS: In genomic analysis, more mutations were found to be drug-resistant after COVID-19 treatment than before COVID-19 treatment. Although it was not possible to demonstrate the usefulness of genome analysis for clinical application, the change of the treatment drug with reference to drug resistance indicated by genomic analysis may lead to good outcome of immunocompromised COVID-19 patients.

Hybrid emergency room: Installation, establishment, and innovation in the emergency department.

A novel trauma workflow system called the hybrid emergency room (Hybrid ER) that combines a sliding computed tomography (CT) scanning system with interventional radiology features was first installed in Osaka General Medical Center in 2011. The Hybrid ER enables CT diagnosis and emergency therapeutic interventions without transferring the patient to another examination room. In this article, the history of CT in trauma care, the world's first installation of the Hybrid ER, clinical experiences, and evidence for the Hybrid ER in trauma workflow and nontrauma fields are summarized, and the future and innovation of the Hybrid ER are reviewed.

Clinical Efficacy of the Neutralizing Antibody Therapy Sotrovimab in Patients with SARS-CoV-2 Omicron BA.1 and BA.2 Subvariant Infections.

Sotrovimab, an antibody active against severe acute respiratory syndrome coronavirus 2 that neutralizes antibodies, reduced the risk of COVID-19-related hospitalization or death in studies conducted before the emergence of the Omicron variant. The objective of this study is to evaluate the clinical efficacy of sotrovimab in patients with mild to moderate COVID-19 Omicron BA.1 and BA.2 subvariant infections using a propensity score matching method. The propensity score-matched cohort study population was derived from patients who received sotrovimab. We derived a comparator group from an age- and sex-matched population who were recuperating in a medical facility after COVID-19 infection or from elderly person entrance facilities during the same period who were eligible for but did not receive sotrovimab treatment. In total, 642 patients in the BA.1 subvariant group and 202 in the BA.2 subvariant group and matched individuals were analyzed. The outcome was the requirement for oxygen therapy. In the treatment group, 26 patients with the BA.1 subvariant and 8 patients with the BA.2 subvariant received oxygen therapy. The administration of oxygen therapy was significantly lower in the treatment group than in the control group (BA.1 subvariant group, 4.0% vs. 8.7%, p = 0.0008; BA.2 subvariant group, 4.0% vs. 9.9%, p = 0.0296). All these patients were admitted to our hospitals and received additional therapy and then recovered. No deaths were observed in either group. Our results demonstrate that the sotrovimab antibody treatment may be associated with a reduction in the requirement for oxygen therapy among high-risk patients with mild to moderate COVID-19 Omicron BA.1 and BA.2 subvariants.

Validation of JRS atypical pneumonia score in patients with community-acquired Chlamydia psittaci pneumonia.

INTRODUCTION: The Japanese Respiratory Society (JRS) atypical pneumonia score is a useful tool for the rapid presumptive diagnosis of atypical pneumonia. We investigated the clinical features of community-acquired pneumonia (CAP) due to Chlamydia psittaci and validated the JRS atypical pneumonia score in patients with C. psittaci CAP. METHODS: This study was conducted at 30 institutions and assessed a total of 72 sporadic cases with C. psittaci CAP, 412 cases with Mycoplasma pneumoniae CAP, and 576 cases with Streptococcus pneumoniae CAP. RESULTS: Sixty-two of 72 patients with C. psittaci CAP had a history of avian exposure. Among the six parameters of the JRS score, matching rates of four parameters were significantly lower in the C. psittaci CAP than the M. pneumoniae CAP in the following parameters: age <60 years, no or minor comorbid illness, stubborn or paroxysmal cough, and absence of chest adventitious sounds. The sensitivity of the diagnosis of atypical pneumonia in patients with C. psittaci CAP was significantly lower than the M. pneumoniae CAP (65.3% and 87.4%, p < 0.0001). When the diagnostic sensitivity was analyzed for different ages, the diagnostic sensitivities for the C. psittaci CAP were 90.5% for non-elderly patients and 30.0% for elderly patients. CONCLUSIONS: The JRS atypical pneumonia score is a useful tool for distinguishing between C. psittaci CAP and bacterial CAP in patients aged <60 years, but not in patients aged ≥60 years. A history of avian exposure in middle-aged patients with normal white blood cell count may be suggestive of C. psittaci pneumonia.

A descriptive study of abdominal complications in patients with mild COVID-19 presenting to the emergency department: a single-center experience in Japan during the omicron variant phase.

BACKGROUND: COVID-19 is widely known to induce a variety of extrapulmonary manifestations. Gastrointestinal symptoms have been identified as the most common extra-pulmonary manifestations of COVID-19, with an incidence reported to range from 3 to 61%. Although previous reports have addressed abdominal complications with COVID-19, these have not been adequately elucidated for the omicron variant. The aim of our study was to clarify the diagnosis of concomitant abdominal diseases in patients with mild COVID-19 who presented to hospital with abdominal symptoms during the sixth and seventh waves of the pandemic of the omicron variant in Japan. METHODS: This study was a retrospective, single-center, descriptive study. In total, 2291 consecutive patients with COVID-19 who visited the Department of Emergency and Critical Care Medicine, Kansai Medical University Medical Center, Osaka, Japan, between January 2022 and September 2022 were potentially eligible for the study. Patients delivered by ambulance or transferred from other hospitals were not included. We collected and described physical examination results, medical history, laboratory data, computed tomography findings and treatments. Data collected included diagnostic characteristics, abdominal symptoms, extra-abdominal symptoms and complicated diagnosis other than that of COVID-19 for abdominal symptoms. RESULTS: Abdominal symptoms were present in 183 patients with COVID-19. The number of patients with each abdominal symptom were as follows: nausea and vomiting (86/183, 47%), abdominal pain (63/183, 34%), diarrhea (61/183, 33%), gastrointestinal bleeding (20/183, 11%) and anorexia (6/183, 3.3%). Of these patients, 17 were diagnosed as having acute hemorrhagic colitis, five had drug-induced adverse events, two had retroperitoneal hemorrhage, two had appendicitis, two had choledocholithiasis, two had constipation, and two had anuresis, among others. The localization of acute hemorrhagic colitis was the left-sided colon in all cases. CONCLUSIONS: Our study showed that acute hemorrhagic colitis was characteristic in mild cases of the omicron variant of COVID-19 with gastrointestinal bleeding. When examining patients with mild COVID-19 with gastrointestinal bleeding, the potential for acute hemorrhagic colitis should be kept in mind.

Assessment of the pneumonia severity score in community-acquired and nursing and healthcare-associated pneumonia due to COVID-19.

INTRODUCTION: The Japanese Respiratory Society (JRS) pneumonia guidelines recommend simple predictive rules, the A-DROP scoring system, for assessment of the severity of community-acquired pneumonia (CAP) and nursing and healthcare-associated pneumonia (NHCAP). We evaluated whether the A-DROP system can be adapted for assessment of the severity of coronavirus disease 2019 (COVID-19) pneumonia. METHODS: Data from 1141 patients with COVID-19 pneumonia were analyzed, comprising 502 patients observed in the 1st to 3rd wave period, 338 patients in the 4th wave and 301 patients in the 5th wave in Japan. RESULTS: The mortality rate and mechanical ventilation rate were 0% and 1.4% in patients classified with mild disease (A-DROP score, 0 point), 3.2% and 46.7% in those with moderate disease (1 or 2 points), 20.8% and 78.3% with severe disease (3 points), and 55.0% and 100% with extremely severe disease (4 or 5 points), indicating an increase in the mortality and mechanical ventilation rates in accordance with severity (Cochran-Armitage trend test; p = <0.001). This significant relationship between the severity in the A-DROP scoring system and either the mortality rate or mechanical ventilation rate was observed in patients with COVID-19 CAP and NHCAP. In each of the five COVID-19 waves, the same significant relationship was observed. CONCLUSIONS: The mortality rate and mechanical ventilation rate in patients with COVID-19 pneumonia increased depending on severity classified according to the A-DROP scoring system. Our results suggest that the A-DROP scoring system can be adapted for the assessment of severity of COVID-19 CAP and NHCAP.

Prognosis of activities of daily living function in hospitalized patients with nursing and healthcare-associated pneumonia due to COVID-19.

Nursing and healthcare-associated pneumonia (NHCAP) is associated with decreased physical function. We investigated the functional outcomes at 1 year after hospital discharge in patients with COVID-19 pneumonia. Functional decline rates for calculating the Barthel Index at the time of hospital discharge and at 1 year after hospital discharge were significantly higher in the NHCAP group than the community-acquired pneumonia group (at hospital discharge, 54.0% vs. 31.2%, respectively, p < 0.0001; 1 year follow-up, 37.9% vs. 8.6%, respectively, p < 0.0001). It is necessary to consider early rehabilitation, and treatment depending on the presence or absence of applicable criteria for NHCAP.

Novel treatment combining antiviral and neutralizing antibody-based therapies with monitoring of spike-specific antibody and viral load for immunocompromised patients with persistent COVID-19 infection.

Because prolonged viral replication of SARS-CoV-2 is increasingly being recognized among immunocompromised patients, subacute or chronic COVID-19 pneumonia can cause persistent lung damage and may lead to viral escape phenomena. Highly efficacious antiviral therapies in immunosuppressed hosts with COVID-19 are urgently needed. From February 2022, we introduced novel treatment combining antiviral therapies and neutralizing antibodies with frequent monitoring of spike-specific antibody and RT-PCR cycle threshold (Ct) values as indicators of viral load for immunocompromised patients with persistent COVID-19 infection. We applied this treatment to 10 immunosuppressed patients with COVID-19, and all completed treatment without relapse of infection. This may be a potentially successful treatment strategy that enables us to sustain viral clearance, determine optimal timing to stop treatment, and prevent virus reactivation in immunocompromised patients with persistent COVID-19.

t6A and ms2t6A Modified Nucleosides in Serum and Urine as Strong Candidate Biomarkers of COVID-19 Infection and Severity.

SARS-CoV-2 infection alters cellular RNA content. Cellular RNAs are chemically modified and eventually degraded, depositing modified nucleosides into extracellular fluids such as serum and urine. Here we searched for COVID-19-specific changes in modified nucleoside levels contained in serum and urine of 308 COVID-19 patients using liquid chromatography-mass spectrometry (LC-MS). We found that two modified nucleosides, N6-threonylcarbamoyladenosine (t6A) and 2-methylthio-N6-threonylcarbamoyladenosine (ms2t6A), were elevated in serum and urine of COVID-19 patients. Moreover, these levels were associated with symptom severity and decreased upon recovery from COVID-19. In addition, the elevation of similarly modified nucleosides was observed regardless of COVID-19 variants. These findings illuminate specific modified RNA nucleosides in the extracellular fluids as biomarkers for COVID-19 infection and severity.

Changes in diagnostic usefulness of the JRS scoring system in COVID-19 pneumonia by SARS-CoV-2 vaccination.

INTRODUCTION: The Japanese Respiratory Society (JRS) scoring system is a useful tool for the rapid presumptive diagnosis of atypical pneumonia in non-elderly (aged <60 years) patients. As SARS-CoV-2 vaccination progresses, COVID-19 in elderly people has markedly reduced. We investigated changes in diagnostic usefulness of the JRS scoring system in COVID-19 pneumonia between the Delta variant group (vaccination period) and non-Delta variant group (before the vaccination period). METHODS: This study was conducted at five institutions and assessed a total of 1121 patients with COVID-19 pneumonia (298 had the Delta variant). During the vaccination period, the Delta variant has spread and replaced the Alfa variant. We evaluated the vaccination period as the Delta variant group. RESULTS: Among the six parameters of the JRS scoring system, matching rates of two parameters were higher in the Delta variant group than the non-Delta variant group (pre-vaccination period): age <60 years (77.5% vs 42.2%, P < 0.0001) and no or minor comorbid illness (69.1% vs 57.8%, p = 0.0007). The sensitivity of the diagnosis of atypical pneumonia in patients with COVID-19 pneumonia was significantly higher in the Delta variant group compared with the non-Delta variant group (80.2% vs 58.3%, p < 0.0001). When the diagnostic sensitivity was analyzed for different ages, the diagnostic sensitivities for the Delta variant and non-Delta variant groups were 92.6% and 95.5% for non-elderly patients and 39.1% and 32.5% for elderly patients, respectively. CONCLUSIONS: Our results demonstrated that the JRS scoring system is a useful tool for distinguishing between COVID-19 pneumonia and bacterial pneumonia in the COVID-19 vaccination period, but not before the vaccination period.

Peak value of serum KL-6 may be useful for predicting poor prognosis of severe COVID-19 patients.

BACKGROUND: Serum Krebs von den Lungen 6 (KL-6), which reflects alveolar epithelial injury, was reported to be useful to predict the progression of pneumonitis induced by COVID-19 in the early phase. This study aimed to evaluate the peak value of serum KL-6 during hospitalization for COVID-19 to discover a more useful biomarker for predicting prognosis in COVID-19 patients. METHODS: In this retrospective, single-center, observational study, we analyzed the data of 147 hospitalized patients who required supplemental oxygen, high-flow oxygen therapy, or invasive mechanical ventilation for respiratory failure due to COVID-19 from March 2020 to February 2021. We extracted data on patient sex, age, comorbidities, treatment, and biomarkers including the initial and peak values of KL-6. Inclusion criteria were examination of the studied biomarkers at least once within 3 days of admission, then at least once a week, and at a minimum, at least twice during the entire hospitalization. Area under the receiver operating curve (AUC) was analyzed to determine the accuracy of several biomarkers including KL-6 and LDH for predicting poor prognosis defined as survivors requiring invasive mechanical ventilation for over 28 days or non-survivors of COVID-19. Univariable and multivariate logistic regression analyses were performed to investigate the prognostic value of the baseline characteristics and biomarkers. RESULTS: Among the 147 patients, 108 (73.5%) had a good prognosis and 39 (26.5%) had a poor prognosis. The AUC analysis indicated that peak KL-6 showed precise accuracy in the discrimination of patients with poor prognosis (AUC 0.89, p < 0.001). The best cut-off value for KL-6 concentration was 966 U/mL (sensitivity 81.6%, specificity84.3%). After adjustment, increasing peak values of KL-6 or LDH were associated with a high risk of poor prognosis, with an adjusted odds ratio of 1.35 for peak value of KL-6, per 100 U/mL increase (95% CI 1.17-1.57, p < 0.001) and 2.16 for peak value of LDH, per 100 U/L increase (95% CI 1.46-3.20, p < 0.001). CONCLUSIONS: Peak values of KL-6 and LDH measured during hospitalization might help to identify COVID-19 patients with respiratory failure who are at higher risk for a poor prognosis.