Radiological Outcomes in Recovered COVID-19 Pneumonia Cases at 1-year Follow-up: The "Post-COVID-19 Lung Study" in Dedicated COVID-19 Care Setting in India.

Abstract

Introduction: Radiological outcomes are initially interpreted as post-COVID-19 lung fibrosis in short-term follow-up of recovered COVID-19 cases in post-COVID-19 care settings and during long-term evaluation, these abnormalities are defined as post-COVID-19 sequalae's. In the present study, post-COVID-19 lung abnormalities were evaluated as "residual lung abnormalities (RLAs)" as radiological outcomes phenotypes.

Methods: Prospective, observational study initially included 1000 COVID-19 reverse transcription-polymerase chain reaction confirmed cases with lung involvement documented and radiological severity phenotypes categorized on high-resolution computerized tomography (HRCT) thorax as mild, moderate, and severe as per lung segment involvement bilaterally at the entry point. Final radiological outcomes were defined by performing a radiological assessment done at 1 year of discharge from the hospital in cases with specified inclusion criteria. Radiological final outcome phenotypes were defined as radiological lung abnormalities (RLAs) and categorized as resolving, persistent, and progressive types documented in HRCT imaging at 1 year of follow-up. Finally, we have included 209 cases with RLAs. Covariates recordings of age, gender, comorbidity, laboratory parameters, and interventions such as oxygen support and oxygen plus ventilatory support requirement during hospitalization were done. Statistical analysis is done using Chi-square test.

Results: RLAs were documented in 20.73% (209/1000) cases. Final radiological outcomes were documented as resolving at 72.24% (151/209), persistent 19.61% (41/209), and progressive 8.13% (17/209). A significant association was documented between RLAs and duration of illness at the entry point (P < 0.00001), laboratory parameters at the entry point (D-dimer, C-reactive protein, interleukin-6) (P < 0.00001), radiological computerized tomography severity phenotypes (P < 0.00001), and interventions required in the indoor unit (P < 0.00001). A significant association was observed between RLAs with covariates such as age, gender, diabetes mellitus, ischemic heart disease, hypertension, chronic obstructive pulmonary disease, obesity, and lung functions assessment by spirometry at 1 year follow-up (P < 0.00001).

Conclusions: Radiological lung abnormalities (RLAs) are new radiological classification of post-COVID-19 lung sequelae and are categorized as resolving, persistent, and progressive. Final outcomes phenotypic classification showed an important role in further workup and treatment plannings of these RLAs during follow-up. Importantly, the proportionate number of progressive phenotypes has underlying rheumatological predisposition, and the large number of cases in resolving phenotypes doesn't need any treatment; whereas few cases in the persistent category need protocolized follow-up.