Coronavirus disease 2019 (COVID-19) has spread worldwide determining a dramatic impact on the healthcare system. Aim of this study is to evaluate mid-term clinical impact of COVID-19 on respiratory function.
379 patients were evaluated 4 months after SARS-COV-2 diagnosis. Patients were divided in two groups based on the presence of pneumonia during COVID. Clinical conditions, quality of life, symptomatology, 6-min walking test, pulmonary function test with spirometry and diffusing capacity of carbon monoxide were analysed. Data were compared to clinical evolution during COVID (development of acute respiratory distress syndrome [ARDS], needing of invasive mechanical ventilation [IMV], partial oxygen saturation/ fraction of inspired oxygen [SpO2/FiO2] ratio and pneumonia severity index [PSI]).
After a median of 135 days, 260 (68.6%) of 379 patients referred almost one symptom. Patients who developed pneumonia during COVID-19 showed lower SpO2 at rest (p<0.001), SpO2 during 6-min walking test (p<0.001), total lung capacity (p<0.001), airway occlusion pressure after 0.1 s [P0.1] (p=0.02), P0.1/maximal inspiratory pressure [MIP] ratio (p=0.005) and higher Borg category-ratio scale (p=0.006) and modified Medical Research Council breathlessness scale (p=0.003), compared to patients without pneumonia. SpO2/FiO2 ratio and PSI during SARS-COV-2 pneumonia were directly associated with mid-term alteration of partial oxygen saturation at rest (p<0.001), SpO2 during 6-min walking test (p<0.001), residual volume (p<0.001), total lung capacity (respectively p<0.001 and p=0.003) and forced vital capacity (respectively p=0.004, p=0.03).
Lung damage during COVID-19 correlates to the reduction of pulmonary function after 4 months from acute infection.