Asthma is a risk factor for general fatigue of long COVID in Japanese nation-wide cohort study.

BACKGROUND: Multiple prolonged symptoms are observed in patients who recover from an acute COVID-19 infection, which is defined as long COVID. General fatigue is frequently observed in patients with long COVID during acute and post-acute phases. This study aimed to identify the specific risk factors for general fatigue in long COVID. METHODS: Hospitalized patients with COVID-19 aged over 18 years were enrolled in a multicenter cohort study at 26 medical institutions. Clinical data during hospitalization and patient-reported outcomes after discharge were collected from medical records, paper-based questionnaires, and smartphone apps. RESULTS: Among prolonged symptoms through 1-year follow-ups, general fatigue was the most interfering symptom in daily life. Patients with protracted fatigue at all follow-up periods had lower quality of life scores at the 12-month follow-up. Univariate logistic regression analysis of the presence or absence of general fatigue at the 3-month, 6-month, and 12-month follow-ups identified asthma, younger age, and female sex as risk factors for prolonged fatigue. Multivariable logistic regression analysis revealed that asthma was an independent risk factor for persistent fatigue during the 12-month follow-up period. Longitudinal changes in the symptoms of patients with or without asthma demonstrated that general fatigue, not cough and dyspnea, was significantly prolonged in patients with asthma. CONCLUSIONS: In a Japanese population with long COVID, prolonged general fatigue was closely linked to asthma. A preventive approach against COVID-19 is necessary to avoid sustained fatigue and minimize social and economic losses in patients with asthma.

Cough and sputum in long COVID are associated with severe acute COVID-19: a Japanese cohort study.

BACKGROUND: Multiple prolonged symptoms are observed in patients who recover from acute coronavirus disease 2019 (COVID-19), defined as long COVID. Cough and sputum are presented by patients with long COVID during the acute and post-acute phases. This study aimed to identify specific risk factors for cough and sputum in patients with long COVID. METHODS: Hospitalized patients with COVID-19 aged 18 years were enrolled in a multicenter cohort study at 26 medical institutions. Clinical data during hospitalization and patient-reported outcomes after discharge were collected from medical records, paper-based questionnaires, and smartphone apps. RESULTS: At the 3-, 6-, and 12-month follow-ups, there were no differences in the incidence rates of wet and dry coughs. In contrast, the proportion of patients presenting sputum without coughing increased over time compared to those with sputum and coughing. Univariate analyses of cough and sputum at all follow-up visits identified intermittent mandatory ventilation (IMV), smoking, and older age as risk factors for prolonged symptoms. At the 12-month follow-up, persistent cough and sputum were associated with the characteristics of severe COVID-19 based on imaging findings, renal and liver dysfunction, pulmonary thromboembolism, and higher serum levels of LDH, KL-6, and HbA1C. The Kaplan-Meier curves showed that the severity of acute COVID-19 infection was correlated with prolonged cough and sputum production. Multivariable logistic regression analysis showed that IMV ventilator management were independent risk factors for prolonged cough and sputum at 12 months. CONCLUSIONS: In a Japanese population with long COVID, prolonged cough and sputum production were closely associated with severe COVID-19. These findings emphasize that a preventive approach including appropriate vaccination and contact precaution and further development of therapeutic drugs for COVID-19 are highly recommended for patients with risk factors for severe infection to avoid persistent respiratory symptoms.

Usefulness of new diagnostic criteria for chronic hypersensitivity pneumonitis established on the basis of a Delphi survey: A Japanese cohort study.

BACKGROUND: Chronic hypersensitivity pneumonitis (CHP) is a fibrotic interstitial lung disease (ILD) caused by repeated exposure to a variety of organic particles. In November 2017, new criteria for CHP diagnosis were proposed by Morisset et al. based on a modified Delphi survey of ILD experts. However, it remains unclear whether these criteria are useful to accurately diagnose CHP. We aimed to evaluate the newly proposed CHP diagnostic criteria. METHODS: We retrospectively applied Morisset's CHP diagnostic criteria to consecutive Japanese patients who underwent surgical lung biopsy for diagnosis of ILD from 2008 to 2015. All patients underwent bronchoalveolar lavage and pulmonary function testing. Patients who had connective tissue disease complications or showed an acute or subacute disease onset were excluded. RESULTS: A total of 251 patients were included. The diagnoses based on multidisciplinary discussion (MDD) were CHP (n = 27), idiopathic pulmonary fibrosis (n = 117), unclassifiable interstitial pneumonia (IP) (n = 65), and other diagnoses (n = 42). Of the 27 MDD-CHP patients, 14 were classified as a CHP group with diagnostic confidence >50% and 13 were not categorized (sensitivity, 51.9%; specificity, 77.7%). Morisset's CHP diagnostic criteria could help avoid SLB for the diagnosis of CHP in seven patients. Of the 13 MDD-CHP patients who were not categorized in the CHP group with diagnostic confidence >50%, the reason for the exclusion was an inconsistent with UIP pattern without CHP features. CONCLUSIONS: Half of the MDD-CHP patients were diagnosed with CHP using Morisset's CHP diagnostic criteria. Further investigation will be important for developing improved diagnostic criteria for CHP.