Lung ultrasound performed by primary care physicians as a predictive and diagnostic tool in COVID-19 patients.

To assess the value of abnormal findings of lung POCUS performed by PCPs in patients with SARS-CoV-2 virus infection in predicting hospitalisations, intensive care admissions, and mortality. Additionally, this study aims to assess the validity of lung POCUS performed by PCPs for COVID-19 pneumonia diagnosis. This prospective observational study, conducted in Mallorca and Salamanca, Spain, during 2021, assessed 624 consecutive adult patients with confirmed SARS-CoV-2 infection and worsening symptoms. Eight PCPs with 5-hour standardized training performed 12-zone lung POCUS. POCUS was considered positive if pleural abnormalities with ≥3 B-lines, subpleural consolidation, or lobar consolidation were present. Patients were followed for 30 days to confirm pneumonia diagnosis via chest X-ray or CT scan. Multivariate models using Poisson regression were performed to identify independent predictors for hospitalization and ICU admission/death. Abnormal POCUS findings were observed in 58.8% of patients, of whom 50.3% presented pleural abnormalities with 3 or more B-lines in at least one scanned area, 27.6% subpleural consolidations, and 3.4% lobar consolidations. Patients with positive POCUS were referred to the hospital more frequently (72.4% vs. 22.8%; OR = 8.83). Abnormal lung POCUS was independently associated with an increased risk of hospitalization (RR 1.34; 95% CI 1.07-1.67), along with age >50 years, SpO2 <95%, hypertension, and diabetes. POCUS was not independently associated with the composite outcome of ICU admission or death (RR 1.27; 95% CI 0.62-2.61). For the diagnosis of COVID-19 pneumonia, overall POCUS sensitivity was 68.3%, specificity 43.6%, positive predictive value 78.7%, and negative predictive value 31.1%. Lung POCUS performed by PCPs is a valuable independent predictor for hospitalization in COVID-19 patients within community settings. While its incremental prognostic benefit over simple clinical variables is modest and its diagnostic accuracy for pneumonia is limited compared to conventional imaging, it could remain as a useful tool for risk stratification in resource-limited environments or home-based care. These findings support its use in resource-limited environments and highlight the need for standardised scanning protocols and training.