ArticleRespiratory research2023
Cough and sputum in long COVID are associated with severe acute COVID-19: a Japanese cohort study.
Article in Respiratory research, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers.
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Who cites it
5 citing papers in PubMed, 7 citations in OpenAlex.
- Inhaled Ciclesonide for Community-Based COVID-19: A Placebo-Controlled Randomised Trial.Respirology (Carlton, Vic.) · 2026Trial
- Clinical outcomes of persistent cough following coronavirus disease 2019 infection: A 1-year retrospective cohort study.Asia Pacific allergy · 2025Article
- Longitudinal Symptom Analysis of COVID-19 Survivors and Post-COVID Syndrome Patients.Biomedicines · 2025Article
- Food and medicine homology: a potential nutritional intervention strategy for post-acute COVID-19 syndrome.Frontiers in pharmacology · 2025Review
- Long COVID Cardiopulmonary Symptoms and Health Resort Treatment: A Retrospective Study.Journal of clinical medicine · 2024Article
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Authors and funding
27 authors at 6 institutions in 1 country.
Funding
Abstract
backgroundMultiple 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.
methodsHospitalized 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.
resultsAt 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.
conclusionsIn 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.
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