Respiratory disease, and treatment / thematic poster session COVID-19 as a cause of pulmonary fibrosis

Rationale: Long term sequelae of COVID-19, especially pertaining to lung structure and function, are largely unknown. Patients with severe COVID-19 who develop acute respiratory distress syndrome (ARDS) requiring prolonged mechanical ventilation are likely at highest risk. We sought to determine the incidence of radiographic markers of lung fibrosis and associated risk factors in a cohort of patients with severe COVID-19. Methods: The Electronic Medical Record at New York University was queried for subjects without a history of interstitial lung disease who had a positive SARS-CoV-2 PCR, required mechanical ventilation, and had a chest computed tomography (CT) conducted during their hospitalization for COVID-19. Clinical and laboratory data was collected. CT scans were blindly read by a thoracic radiologist using a novel scoring system where fibrotic changes were defined as consolidation and/or ground glass with traction, and honeycombing. The prevalence of fibrosis was established and analyses were done to evaluate for clinical associations. Data is represented as number of patients (percent of cohort), and mean ± standard deviation). Results: 88 patients were included, 61 (69.3%) had fibrotic changes on CT done 50.3 ± 33.6 days after admission, while 27 (30.7%) had no fibrosis seen on CT done 41.5 ± 26.0 days after admission. There were no significant differences in demographics or medical history between the subgroups. The fibrotic subgroup required mechanical ventilation for a longer duration than the non-fibrotic subgroup (52.8 ± 33.2 vs 32.1 ± 18.8 days) and had higher plateau pressures 21 days after intubation (26.6 ± 6.0 vs 16.5 ± 5.4 cmH2O). P/F ratios were similar on day of intubation (145.4 ± 55.5 fibrotic vs 145.7 ± 64.1 non-fibrotic), however the fibrotic subgroup had lower P/F ratios 7 days after intubation (146.3 ± 57.0 vs 182.1 ± 63.3), 14 days after intubation (166.3 ± 83.7 vs 236.8 ± 84.3), and 21 days after intubation (170.8 ± 90.5 vs 249.5 ± 103.0). The fibrotic subgroup also had higher peak ferritin (8899.92 ± 11461.3 vs 6715.6 ± 9680.1 ng/mL) and LDH (1031.67 ± 628.9 vs 929.0 ± 493.3 U/L). Conclusion: In our cohort of severe COVID-19 patients, over two-thirds had fibrotic changes on CT chest. Longer duration of mechanical ventilation, higher plateau pressures 21 days after intubation, lower P/F ratios 7 days or more after intubation, and higher peak ferritin and LDH levels were associated with presence of fibrosis. .