Lung Ultrasound Abnormalities and LUS Score After COVID-19 Pneumonia: Determinants and Associations with Dyspnoea in a Prospective Cohort

Background/Objectives: The clinical determinants and functional relevance of persistent lung ultrasound (LUS) abnormalities after COVID-19 pneumonia remain poorly characterized. We aimed to identify determinants of qualitative LUS abnormalities and global lung involvement assessed by the LUS score, and to evaluate their association with persistent dyspnoea. Methods: We conducted a prospective observational study that included 261 patients who were hospitalized for COVID-19 pneumonia and were assessed 1–6 months after discharge. A standardized 14-zone LUS protocol was used to assess qualitative abnormalities (pleural line irregularity, ≥3 B-lines, and subpleural consolidations) and to calculate the LUS score. Associations with clinical variables, including dyspnoea assessed by the modified Medical Research Council (mMRC) scale, were analyzed using multivariable logistic regression. Results: The severity of the acute pneumonia episode emerged as the strongest determinant of qualitative LUS abnormalities and elevated LUS score (>6). Increasing age was independently associated with ultrasound findings. Persistent dyspnoea (mMRC ≥ 1) was associated with all qualitative abnormalities and with a higher prevalence of elevated LUS score (56.6% vs. 22.1%; p < 0.001). A graded association was observed between dyspnoea severity and both qualitative findings and LUS score. An increase in dyspnoea from baseline (ΔmMRC ≥ 1) remained independently associated with an elevated LUS score. Conclusions: Persistent LUS abnormalities are strongly associated with the severity of the acute episode. The LUS score provides a robust, clinically meaningful measure of residual lung involvement and shows a stronger association with persistent dyspnoea than qualitative findings, supporting its role in follow-up and risk stratification.