Publication date: Jul 09, 2025

Background: Patients with mild coronavirus disease 2019 (COVID-19) are usually managed in an outpatient setting. Pulmonary functions in this setting have not been explored. This study aimed to determine abnormal lung functions in COVID-19 patients under a home isolation program. Methods: A prospective study was conducted in asymptomatic or mild COVID-19 patients with normal chest radiographs at two medical centers in Thailand. Spirometry data, including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), forced expiratory flow at 25-75% of FVC (FEF25-75), and bronchodilator responsiveness (BDR), were collected. Spirometry was performed after disease resolution at baseline and 3-month follow-up. Abnormal lung functions were classified into airway obstruction, restrictive defect, mixed defect, small airway disease, and BDR. Results: A total of 250 patients (58% female) were included. The mean age was 37. 4 +/- 15. 2 years. Asymptomatic patients accounted for 7. 6%. Common symptoms included fever (55. 6%) and cough (60. 0%). Abnormal lung functions were observed in 28. 4% of patients, with a restrictive lung pattern (14. 4%), airway obstruction (4. 8%), mixed defect (0. 4%), small airway disease (8. 4%), and BDR (2. 8%). Significant changes from baseline were noted in FVC (1. 21%), FEV/FVC (-1. 51%predicted), PEF (0. 06%), and FEF (-2. 76%). Logistic regression analysis indicated that a higher body mass index was associated with a lower risk of abnormal lung function. Conclusions: Ventilatory defects were observed in one-third of patients with mild COVID-19 who did not require hospitalization, mainly presenting as restrictive patterns and small airway disease. Even mild cases may have residual pulmonary impairment, warranting further long-term studies.

Open Access PDF

Semantics

Original Article