Covid -19 virus popularly known to cause acute respiratory syndrome has also reportedly affected most patients who have recovered from acute COVID-19 experience long-term effects on multiple organs and systems . In most cases, persistent symptoms resolve over several months. However, some patients experience systemic symptoms that persist for more than 3–24 months.
In a current Japanese population with long COVID, prolonged cough and sputum production were closely associated with severe COVID-19. The study published in Respiratory Research emphasizes on 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.
Prolonged symptoms are reported 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.
Researchers in the current study aimed to identify specific risk factors for cough and sputum in patients with long COVID. 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.
The key findings of the study are
• Researchers found 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.
Researchers concluded that “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.”
Reference: Watase, M., Miyata, J., Terai, H. et al. Cough and sputum in long COVID are associated with severe acute COVID-19: a Japanese cohort study. Respir Res 24, 283 (2023). https://doi.org/10.1186/s12931-023-02591-3.