Initial severity of COVID-19 correlates with adverse pulmonary outcome 1 year later

Initial severity of COVID-19 respiratory failure was associated with the degree of pulmonary impairment and respiratory quality of life 1 year after infection, according to results published in Respiratory Medicine.

The ongoing single-center, prospective, observational study included 180 patients with acute COVID-19 (median age, 57 years; 37.8% women) who were followed up as outpatients from May 2020 to June 2021. At 6 weeks, 3, 6 and 12 months after COVID-19 symptom onset, patients underwent chest CT scans to assess pulmonary function and completed the St. George’s Respiratory Questionnaire to assess symptoms. Researchers categorized patients based on severity of acute infection.

Three-quarters of patients were initially hospitalized. The median age of patients increased with the level of respiratory support required: 44 years in those never hospitalized; median age, 56 years in those who required extracorporeal membrane oxygenation; 61 years in those who required mechanical ventilation.

Older age (P < .0001), male sex (P = .001) and higher BMI (P = .004) were all associated with severity of acute COVID-19. In addition, pulmonary restriction (P < .0001) and reduced carbon monoxide diffusion capacity (P = .01) were also associated with COVID-19 severity.

Pulmonary restriction occurred in 32% of patients, and reduced carbon monoxide diffusion capacity was observed in 61%.

Over 12 months, among patients with pulmonary restriction and impaired carbon monoxide diffusion capacity, there was an improvement in FVC (P = .002), total lung capacity (P= .045), diffusing capacity of carbon monoxide (P = .0002) and diffusion coefficient (P = .0005).

Researchers reported an association between the CT score of lung involvement in the acute COVID-19 phase and pulmonary restriction and reduction in diffusion capacity during follow-up.

Fatigue, dyspnea, cough, cognitive impairment and joint pain were the most commonly reported symptoms within 1 year. At 1 year, more than 60% of patients reported fatigue, 43% shortness of breath and 23% persistent cognitive impairment. Respiratory symptoms improved during follow-up for patients with higher disease severity, but the same was not observed among patients with initially mild COVID-19.

According to the researchers, through summarizing these results and the evolution of findings over time, there are two main patterns of pulmonary involvement discernible after COVID-19.

“We were surprised to see two different phenotypes of lung affection; one group with the most severe initial disease developed persisting pulmonary restriction as expected, but another group of patients with initially mild disease showed another pattern of restriction caused predominantly by a loss of ventilated area,” Thomas Zoller, MD, from the department of infectious diseases and respiratory medicine at the Free University of Berlin and Humboldt University of Berlin and the Swiss Tropical and Public Health Institute, Basel, Switzerland, told Healio. “Interestingly, this group of patients also had a persisting symptom load over the follow-up period, whereas symptoms diminished over time in initially more severely affected patients.”

Zoller said this finding requires further characterization in the future.

“The next step is to confirm and investigate our findings in more detail in larger and multicentric cohort studies,” Zoller said. “Moreover, correlation of our findings with biomarkers and -omics research is essential.”

For more information:

Thomas Zoller, MD, can be reached at thomas.zoller@charite.de.