Simple clinical score for rational use of lung ultrasound in COVID-19 outpatient settings

Abstract

INTRODUCTION: Due to the rapid global expansion of COVID-19, Febrile Emergency Units (FEU) were created in the outpatient setting to stratify the clinical risk of patients. Pulmonary ultrasound has gained a growing interest as a sensitive method for the detection of pneumonia. This study aimed to at developing a simple and sensitive score to assess the risk of pneumonia during the first COVID-19 wave. METHODS: A cross-sectional study was conducted in a cohort of adult patients with laboratory-confirmed COVID-19, who received care at the FEU of a general hospital in the city of Buenos Aires from May through August 2020. Bivariate and multivariate analyses of sociodemographic and clinical variables were performed to build and internally validate a pneumonia predictive score. RESULTS: The final analysis included 936 patients; 17.6% had ultrasound compatible with pneumonia. The score included 5 statistically significant variables: age ≥50 years (3 points), cough (2 points), absence of odynophagia (1 point), dyspnea (2 points) and oxygen saturation ≤95% (3 points). A cut-off point ≥3 showed a sensitivity of 80.5% and a negative predictive value of 93.3%, with good discriminatory capacity both in derivation and validation cohorts (area under ROC curve 0.79 and 0.76, respectively). DISCUSSION: This score could be a useful tool to stratify the clinical risk of pneumonia in the pre-hospital setting and avoid imaging studies with a score <3.