Shoichiro Hamada

Bio: Shoichiro Hamada is an academic researcher from Kyorin University. The author has contributed to research in topics: Retrospective cohort study & Cohort study. The author has an hindex of 1, co-authored 4 publications receiving 4 citations.

Abnormal pulmonary function and imaging studies in critical COVID-19 survivors at 100 days after the onset of symptoms.

Abstract: Background The long-term repercussions of critical COVID-19 on pulmonary function and imaging studies remains unexplored. In this study, we investigated the pulmonary function and computed tomography (CT) findings of critical COVID-19 patients approximately 100 days after symptom onset. Methods We retrospectively extracted data on critical COVID-19 patients who received invasive mechanical ventilation during hospitalization from April to December 2020 and evaluated their pulmonary function, residual respiratory symptoms and radiographic abnormalities on CT. Results We extracted 17 patients whose median age was 63 (interquartile range [IQR], 59–67) years. The median lengths of hospitalization and mechanical ventilation were 23 (IQR, 18–38) and 9 (IQR, 6–13) days, respectively. At 100 days after symptom onset, the following pulmonary function abnormalities were noted in 8 (47%) patients: a diffusion capacity of the lung for carbon monoxide (%DLCO) of Conclusions Over 90% of the critical COVID-19 patients who underwent invasive mechanical ventilation continued presenting with abnormal imaging studies and 47% of the patients presented with abnormal pulmonary function 100 days after symptom onset. The extent of the residual CT findings might be associated with the degree of abnormal pulmonary function in critical COVID-19 survivors.

Association between adjunct clindamycin and in-hospital mortality in patients with necrotizing soft tissue infection due to group A Streptococcus: a nationwide cohort study.

Abstract: Necrotizing soft tissue infection (NSTI) due to group A Streptococcus (GAS) is a severe life-threatening microbial infection. The administration of adjunct clindamycin has been recommended in the treatment of NSTIs due to GAS. However, robust evidence regarding the clinical benefits of adjunct clindamycin in NSTI patients remains controversial. We aimed to investigate the association between early administration of adjunct clindamycin and in-hospital mortality in patients with NSTI attributed to GAS. The present study was a nationwide retrospective cohort study, using the Japanese Diagnosis Procedure Combination inpatient database focusing on the period between 2010 and 2018. Data was extracted on patients diagnosed with NSTI due to GAS. We compared patients who were administered clindamycin on the day of admission (clindamycin group) with those who were not (control group). A propensity score overlap weighting method was adopted to adjust the unbalanced backgrounds. The primary endpoint was in-hospital mortality and survival at 90 days after admission. We identified 404 eligible patients during the study period. After adjustment, patients in the clindamycin group were not significantly associated with reduced in-hospital mortality (19.2% vs. 17.5%; odds ratio, 1.11; 95% confidence interval, 0.59–2.09; p = 0.74) or improved survival at 90 days after admission (hazard ratio, 0.92; 95% confidence interval, 0.51–1.68; p = 0.80). In this retrospective study, early adjunct clindamycin does not appear to improve survival. Therefore, the present study questions the benefits of clindamycin as an adjunct to broad spectrum antibiotics in patients with NSTI due to GAS.

Prevalence of COVID-19 Mimics in the Emergency Department.

Abstract: Objective Due to the lack of specific clinical manifestations and symptoms, it is difficult to distinguish COVID-19 from mimics. A common pitfall is to rush to make a diagnosis when encountering a patient with COVID-19-like symptoms. The present study describes a series of COVID-19 mimics using an outpatient database collected from a designated COVID-19 healthcare facility in Tokyo, Japan. Methods We established an emergency room (ER) tailored specifically for patients with suspected or confirmed COVID-19 called the "COVID-ER." In this single-center retrospective cohort study, we enrolled patients who visited the COVID-ER from February 1 to September 5, 2020. The outcomes included the prevalence of COVID-19, admission, potentially fatal diseases and final diagnosis. Results We identified 2,555 eligible patients. The median age was 38 (interquartile range, 26-57) years old. During the study period, the prevalence of COVID-19 was 17.9% (457/2,555). Non-COVID-19 diagnoses accounted for 82.1% of all cases. The common cold had the highest prevalence and accounted for 33.0% of all final diagnoses, followed by gastroenteritis (9.4%), urinary tract infections (3.8%), tonsillitis (2.9%), heat stroke (2.6%) and bacterial pneumonia (2.1%). The prevalence of potentially fatal diseases was 16.2% (298/2,098) among non-COVID-19 patients. Conclusion Several potentially fatal diseases remain masked among the wave of COVID-19 mimics. It is imperative that a thorough differential diagnostic panel be considered prior to the rendering of a COVID-19 diagnosis.

In‐hospital mortality among patients with invasive non‐group A β‐hemolytic Streptococcus treated with clindamycin combination therapy: a nationwide cohort study

Abstract: Aim Combination treatment with clindamycin is recommended in patients with invasive group A Streptococcus infection; however, whether the same treatment is effective in invasive group B Streptococcus and S. dysgalactiae subspecies equisimilis infections remains unknown. We aimed to investigate whether clindamycin added to standard of care therapy would be effective in patients with invasive non-group A β-hemolytic Streptococcus infections. Methods This was a nationwide retrospective cohort study using the Japanese Diagnosis Procedure Combination inpatient database focusing on the period between 2010 and 2018. We extracted data on patients diagnosed with sepsis due to non-group A β-hemolytic Streptococcus. One-to-four propensity score-matching was undertaken to compare patients who were treated with clindamycin within 2 days of admission (clindamycin group) and those who did not (control group). The primary outcome was in-hospital mortality. Results We identified 3754 eligible patients during the study period. The patients were divided into the clindamycin (n = 296) and control groups (n = 3458). After one-to-four propensity score matching, we compared 289 and 1156 patients with and without clindamycin, respectively. In-hospital mortality did not significantly differ between the two groups (9.7% versus 10.3%; risk difference 0.3%; 95% confidence interval, -3.5% to 4.2%). Conclusions This nationwide database study showed that combination therapy involving the use of clindamycin was not associated with lower in-hospital mortality in patients with invasive non-group A β-hemolytic Streptococcus.

Parenchymal lung abnormalities following hospitalisation for COVID-19 and viral pneumonitis: a systematic review and meta-analysis

Abstract: Introduction Persisting respiratory symptoms in COVID-19 survivors may be related to development of pulmonary fibrosis. We assessed the proportion of chest CT scans and pulmonary function tests consistent with parenchymal lung disease in the follow-up of people hospitalised with COVID-19 and viral pneumonitis. Methods Systematic review and random effects meta-analysis of proportions using studies of adults hospitalised with SARS-CoV-2, SARS-CoV, MERS-CoV or influenza pneumonia and followed up within 12 months. Searches performed in MEDLINE and Embase. Primary outcomes were proportion of radiological sequelae on CT scans; restrictive impairment; impaired gas transfer. Heterogeneity was explored in meta-regression. Results Ninety-five studies (98.9% observational) were included in qualitative synthesis, 70 were suitable for meta-analysis including 60 SARS-CoV-2 studies with a median follow-up of 3 months. In SARS-CoV-2, the overall estimated proportion of inflammatory sequelae was 50% during follow-up (0.50; 95% CI 0.41 to 0.58; I2=95%), fibrotic sequelae were estimated in 29% (0.29; 95% CI 0.22 to 0.37; I2=94.1%). Follow-up time was significantly associated with estimates of inflammatory sequelae (−0.036; 95% CI −0.068 to –0.004; p=0.029), associations with fibrotic sequelae did not reach significance (−0.021; 95% CI −0.051 to 0.009; p=0.176). Impaired gas transfer was estimated at 38% of lung function tests (0.38 95% CI 0.32 to 0.44; I2=92.1%), which was greater than restrictive impairment (0.17; 95% CI 0.13 to 0.23; I2=92.5%), neither were associated with follow-up time (p=0.207; p=0.864). Discussion Sequelae consistent with parenchymal lung disease were observed following COVID-19 and other viral pneumonitis. Estimates should be interpreted with caution due to high heterogeneity, differences in study casemix and initial severity. PROSPERO registration number CRD42020183139.

Post-COVID-19 Syndrome

Abstract: Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, many individuals have reported persistent symptoms and/or complications lasting beyond 4 weeks, which is now called post-COVID-19 syndrome. SARS-CoV-2 is a respiratory coronavirus that causes COVID-19, and injury to the lungs is expected; however, there is often damage to numerous other cells and organs, leading to an array of symptoms. These long-term symptoms occur in patients with mild to severe COVID-19; currently, there is limited literature on the potential pathophysiological mechanisms of this syndrome.The purpose of this integrative review is to summarize and evaluate post-COVID-19 syndrome from a biological perspective.An integrative review was conducted using Whittemore and Knafl's methodology for literature published through August 30, 2021. The PubMed, CINAHL, and Web of Science databases were searched for articles published as of August 30, 2021, using combinations of the following key words: post-COVID-19 syndrome, post-SARS-CoV-2, long COVID-19, long COVID-19 syndrome, and pathophysiology of post-COVID-19. Data were analyzed using the constant comparison method.The search generated 27,929 articles. After removing duplicates and screening abstracts and full-text reviews, we retained 68 articles and examined 54 specific articles related to the pathophysiology of post-COVID-19 syndrome. The findings from our review indicated that there were four pathophysiological categories involved: virus-specific pathophysiological variations, oxidative stress, immunologic abnormalities, and inflammatory damage.Although studies examining the pathophysiology of post-COVID-19 syndrome are still relatively few, there is growing evidence that this is a complex and multifactorial syndrome involving virus-specific pathophysiological variations that affect many mechanisms but specifically oxidative stress, immune function, and inflammation. Further research is needed to elucidate the pathophysiology, pathogenesis, and longer term consequences involved in post-COVID-19 syndrome.

Post-viral parenchymal lung disease of COVID-19 and viral pneumonitis: A systematic review and meta-analysis.

Abstract: BackgroundApproximately half of patients discharged following COVID-19 related hospitalisation are reported to suffer from persisting respiratory symptoms. We assess the prevalence of long term radiological and functional pulmonary sequelae in survivors from COVID-19 and other viral pneumonia in published literature. MethodsWe performed systematic review and meta-analysis of all original studies in adults admitted to hospital with SARS-CoV-2, SARS-CoV, MERS-CoV, or Influenza pneumonia and followed within 12 months from discharge. Searches were run on MEDLINE and Embase, with the last update on 1st March 2021. Primary outcomes were presence of 1) radiologic sequelae at CT scans; 2) restrictive impairment; 3) reduced diffusing capacity for carbon monoxide (DLCO). This review is registered on PROSPERO, CRD42020183139. ResultsSixty studies were included for qualitative synthesis, of which 41 were suitable for meta-analysis. On follow up CT scans, the overall estimated proportion was 0{middle dot}56 (95%CI 0{middle dot}44 to 0{middle dot}66, I2= 94{middle dot}44%) for inflammatory changes, and 0{middle dot}40 (95%CI 0{middle dot}29 to 0{middle dot}52, I2=95{middle dot}19%) for fibrotic findings. In SARS-CoV-2 specifically, proportions were estimated at 0{middle dot}43 (95%CI 0{middle dot}32 to 0{middle dot}56, I2=94.60%) and 0{middle dot}30 (95%CI 0{middle dot}19 to 0{middle dot}43, I2=94.89%) for inflammatory and fibrotic findings, respectively. Overall proportion for restrictive impairment was 0{middle dot}19 (95%CI 0{middle dot}12 to 0{middle dot}27, I2=94{middle dot}46%), DLCO reduction was estimated at 0{middle dot}45 (95%CI 0{middle dot}38 to 0{middle dot}52, I2=90{middle dot}10). Elevated radiological and functional estimates persisted across follow-up times. Confidence in the estimates was deemed very low as studies were largely observational without control groups, heterogeneity in estimates was high but was not clearly attributable to between-study differences of severity or design. ConclusionAlthough estimates of prevalence are likely limited by differences in case mix and initial severity, a substantial proportion of radiological and functional sequelae are observed following viral pneumonitis, including COVID-19. This highlights the importance of vigilant radiological and functional follow up. FundingNational Institute for Health Research (NIHR)

Role of antifibrotic drugs in the management of post-COVID-19 interstitial lung disease: A review of literature and report from an expert working group

Abstract: 177 Virus-induced alveolar epithelial cell lung injury, abnormal immune response, and attempts at healing are central to the process of viral-induced lung fibrogenesis. SARS survivors who were followed over 1 year after the infection showed abnormal radiological features in 28% and reduced DLCO in 24%, and the extent of radiographic abnormalities correlated with the severity of functional improvement.[9] Another 2-year follow-up study of 55 patients who survived SARS ARDS showed a reduction in DLCO in 53% of patients.[10] Approximately one-third of the survivors of SARS have been shown to have significant pulmonary fibrosis.[11] As there are similarities between SARS-CoV-1 and SARS-CoV-2, it seems likely that lung fibrosis may be a common long-term consequence of COVID-19 pneumonia.[12]

Pulmonary function test and computed tomography features during follow-up after SARS, MERS and COVID-19: a systematic review and meta-analysis

Abstract: Background The COVID-19 pandemic follows severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronavirus epidemics. Some survivors of COVID-19 infection experience persistent respiratory symptoms, yet their cause and natural history remain unclear. Follow-up after SARS and MERS may provide a model for predicting the long-term pulmonary consequences of COVID-19. Methods This systematic review and meta-analysis aims to describe and compare the longitudinal pulmonary function test (PFT) and computed tomography (CT) features of patients recovering from SARS, MERS and COVID-19. Meta-analysis of PFT parameters (DerSimonian and Laird random-effects model) and proportion of CT features (Freeman-Tukey transformation random-effects model) were performed. Findings Persistent reduction in the diffusing capacity for carbon monoxide following SARS and COVID-19 infection is seen at 6 months follow-up, and 12 months after MERS. Other PFT parameters recover in this time. 6 months after SARS and COVID-19, ground-glass opacity, linear opacities and reticulation persist in over 30% of patients; honeycombing and traction dilatation are reported less often. Severe/critical COVID-19 infection leads to greater CT and PFT abnormality compared to mild/moderate infection. Interpretation Persistent diffusion defects suggestive of parenchymal lung injury occur after SARS, MERS and COVID-19 infection, but improve over time. After COVID-19 infection, CT features are suggestive of persistent parenchymal lung injury, in keeping with a post-COVID-19 interstitial lung syndrome. It is yet to be determined if this is a regressive or progressive disease.