Six-month pulmonary impairment after severe COVID-19: a prospective, multicenter follow-up study

ABSTRACT

Background and objectiveLong-term pulmonary sequelae following SARS-CoV-2 pneumonia are not yet confirmed, however preliminary observations suggests a possible relevant clinical, functional and radiological impairment. The aim of this study was to identify and characterise pulmonary sequelae caused by SARS-CoV-2 pneumonia at 6-month follow-up. MethodsIn this multicenter, prospective, observational cohort study, patients hospitalised for SARS-CoV-2 pneumonia and without prior diagnosis of structural lung diseases were stratified by maximum ventilatory support ("oxygen only", "continuous positive airway pressure (CPAP)" and "invasive mechanical ventilation (IMV)") and followed up at 6 months from discharge. Pulmonary function tests and diffusion capacity for carbon monoxide (DLCO), 6 minutes walking test, chest X-ray, physical exam and modified Medical Research Council (mMRC) dyspnoea score were collected. ResultsBetween March and June 2020, 312 patients were enrolled (83, 27% women; median [IQR] age 61.1 [53.4,69.3] years). The parameters that showed the highest rate of impairment were DLCO and chest-X-ray, in 46% and 25% of patients, respectively. However, only a minority of patients reported dyspnoea (31%), defined as mMRC [≥] 1, or showed a restrictive ventilatory defects (9%). In the logistic regression model, having asthma as comorbidity was associated with DLCO impairment at follow-up, while prophylactic heparin administration during hospitalisation appeared as a protective factor. Need for invasive ventilatory support during hospitalisation was associated with chest imaging abnormalities. ConclusionDLCO and radiological assessment appear to be the most sensitive tools to monitor patients with COVID-19 during follow-up. Future studies with longer follow-up are warranted to better understand pulmonary sequelae. Summary at a glanceDLCO and radiological assessment are the most sensitive tools to monitor COVID-19 patients at 6-month follow-up. Invasive ventilatory support is a risk factor for detection of radiological abnormalities, but not for DLCO impairment, at follow-up. Whileuse of prophylactic heparin acts as a protective factor on the development of DLCOimpairment.