COVID-19 Lung Involvement Captured on CT Can Help Predict Mortality Risk

Chest CT scans can provide a volumetric analysis of lung consolidation in COVID-19-positive patients, helping providers with care management and better enabling them to pinpoint which patients could die in the hospital from the virus.

In a study published Jan. 6 in the European Journal of Radiology Open, investigators from Michigan State University examined whether the percentage of lung involvement on initial chest CT is directly related to the likelihood of a patient with the virus dying while admitted.

They used radiation therapy planning software to evaluate the impact of lung involvement and discovered that the risk of in-hospital mortality increased with each unit percentage of lung involvement by consolidations. In addition, these patients face a higher likelihood of experiencing major adverse hospital events.

The team was led by Lucas G. Sapienza, M.D., a resident at Baylor College of Medicine during his internship at Ascension Providence Hospital associated with Michigan State University College of Human Medicine.

“Among patients hospitalized with COVID-19, more lung consolidation on chest CT increases the risk of in-hospital death,” the team wrote. “Therefore, this study provides evidence that chest CT is a potential tool in guiding escalation or de-escalation of care in the hospital setting.”

Based on their evaluations, they anticipated by proportionally reflecting lung parenchyma impairment that the number of opacities relative to the total lung volume could be used to predict which patients would need more intense medical management, as well as survival.

Sapienza’s team tested their hypothesis by using radiotherapy planning software to run a volumetric analysis of the lung opacities on chest CT scans from 154 patients who had laboratory confirmed COVID-19 pneumonia between February 2020 and April 2020. According to their analysis, the median relative lung involvement was 28.8 percent with 26.3 percent of patients being intubated. Of these patients, 16.2 percent – 25 patients – died.

After adjusting for significant clinical factors, the team said, there was a 3.6-percent increase in the chance of dying in the hospital and a 2.5-percert increase in experiencing a major adverse hospital even for every percentage unit of lung involvement. Advanced age at the time of hospital admission, having a do-not-resuscitate (DNR) or do-not-intubate (DNI) order, and a history of smoking increased the likelihood of a patient dying in the hospital, they found, and older men had the highest risk of adverse events.

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These findings can offer important details that can guide clinical management, the team said.

“For example, a patient who is more than 65 years of age and has a history of smoking has a 15 percent risk of dying during hospitalization if 10 percent of the lung is involved at the initial assessment,” they noted. “That risk would escalate to 50 percent for a similar patient with 60 percent of lung involvement.”

In addition, patients with a DNR or DNI had a 20 times higher chance of in-hospital mortality.

Providers may be able to use these results to better focus their efforts as the pandemic continues, the team said.

“In this scenario, tools to predict outcomes would be important to better triage patients who require more intensive support,” they said. “On the other hand, patients who had a limited risk of developing major adverse events could be managed in a lower complexity facility or from home.”

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