Chest. 2021 Jan 28:S0012-3692(21)00209-9. doi: 10.1016/j.chest.2021.01.053. Online ahead of print.
BACKGROUND: Chest radiography is often performed in the acute setting to help understand the extent of respiratory disease in patients with COVID-19, but a clearly defined role for negative chest radiographs in assessing patients has not been described.
RESEARCH QUESTION: Is portable chest radiography an effective exclusionary test for future adverse clinical outcomes in patients suspected of COVID-19?
STUDY DESIGN AND METHODS: Charts of consecutive patients suspected of COVID-19 at five emergency departments in New York City between March 19, 2020 through April 23, 2020 were reviewed. Patients were categorized based on absence of findings on initial chest radiography (CXR). The primary outcomes were hospital admission, mechanical ventilation, acute respiratory distress syndrome (ARDS), and mortality.
RESULTS: 3245 adult patients, 474 (14.6%) with a negative initial CXR, were reviewed. Among all patients, a negative initial CXR is associated with a low probability of future adverse clinical outcomes, with negative likelihood ratios of 0.27 (95% CI 0.23-0.31) for hospital admission, 0.24 (95% CI 0.16-0.37) for mechanical ventilation, 0.19 (95% CI 0.09-0.40) for ARDS, and 0.38 (95% CI 0.29-0.51) for mortality. Among the subset of 955 patients younger than 65 years old and with a duration of symptoms of at least 5 days, no patients with a negative CXR died and the negative likelihood ratios were 0.17 (95% CI 0.12-0.25) for hospital admission, 0.09 (95% CI 0.02-0.36) for mechanical ventilation, and 0.09 (95% CI 0.01-0.64) for ARDS.
INTERPRETATION: Initial chest radiography in adult patients suspected of COVID-19 is a strong exclusionary test for hospital admission, mechanical ventilation, ARDS, and mortality. The value of chest radiography as an exclusionary test for adverse clinical outcomes is highest among young adults, patients with few comorbidities, and those with a prolonged duration of symptoms.