Introduction
Coronavirus disease-19 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has affected over 150 million people around the world as of April 28, 20211.
The onset symptoms of COVID-19 are fever, fatigue, shortness of breath, and a dry cough2,3. Typically chest tomography findings are peripheral, subpleural ground-glass opacities, bilaterally patchy shadows2,4,5 and chest computed tomography (CT) findings are related to disease severity6,7. Although most cases were classified as mild, 14% of cases were severe and 5% of them were critical, requiring intensive care unit (ICU) admission8. Studies focus on pathogenesis, clinical manifestations, and complications during the early phase of the disease9–13, but long-term outcomes still remain unclear.
Some of the patients recovered completely, but some patients were unable to reach their former health status, despite a long recovery period. Symptoms such as fatigue and dyspnea persist in half of the patients who were discharged from hospital14,15. CT findings are reversible in the majority of COVID-19 patients16. However, data on improvement of CT findings in ICU patients who have higher CT scores are lacking. Complete recovery may take a long time in mild and moderate cases as well as in severe patients who require ICU admission. More studies are needed on long-term outcomes in the post-COVID period17, especially in ICU patients.
The aim of this study was to evaluate the long-term effects of COVID-19 on lung structures, pulmonary functions, exercise capacity and quality of life in discharged ICU patients and compare these findings with hospitalized non-ICU patients.