LAUSR

Background The long-term pulmonary sequelae of coronavirus disease 2019 (COVID-19) is not well known. Purpose To characterize patterns and rates of improvement of chest CT abnormalities one year after COVID-19 pneumonia. Materials and Methods This was a secondary analysis of a prospective, multicenter observational cohort study conducted from April 29 to August 12, 2020 to assess pulmonary abnormalities on chest CT at approximately 2, 3, 6 months, and 1 year after onset of COVID-19 symptoms. Pulmonary findings were graded for each lung lobe using a qualitative CT severity score (CTSS), range 0 (normal) to 25 (all lobes involved). The association of demographic and clinical factors with CT abnormalities after 1 year was assessed with logistic regression. The rate of change of the CTSS at follow-up CT was investigated by Friedmann test. Results Out of 142 enrolled participants, 91 participants had a 1-year follow-up CT and were included in the analysis [mean age, 59 years ± 13 [standard deviation]; 35 women (38%)]. In 49/91 (54%) participants, CT abnormalities were observed: 31/91 (34%) participants showed subtle subpleural reticulation, ground-glass opacities or both and 18/91 (20%) participants revealed extensive ground-glass opacities, reticulations, bronchial dilation and/or microcystic changes. In multivariable analysis, age > 60 years (OR 5.8 [95% CI: 1.7 - 24]; p = .009) critical COVID-19 severity (OR 29 [95% CI: 4.8 - 280]; p < .001) and male gender (OR 8.9 [95% CI: 2.6 - 36]; p < .001) were associated with persistent CT abnormalities at 1 year. Reduction of CTSS was observed in participants in subsequent follow-up CTs (p < .001) and during the study period 49% (69/142) of participants had complete resolution of CT abnormalities. 31/49 (63%) participants with CT abnormalities did not show further improvement after 6 months. Conclusion Long-term CT abnormalities were common 1 year after COVID-19 pneumonia. The study is registered at ClinicalTrials.gov number (registration number NCT04416100). See also the editorial by Leung.