Introduction:

Currently there are no blood biomarkers to identify patients with PF secondary to COVID-19 pneumonia. The ELF score is a panel of serum markers of liver fibrosis; however, it has also been used in PF. We analyse the ELF score as a serum biomarker of PF due to COVID-19 pneumonia.

Methods:

Pilot study performed in a random sample of patients recovered from COVID-19 pneumonia. Chest computed tomography (CT) scan and lung function tests (LFTs) at 3 months after discharge were collected. Data were analysed according to ELF scores and posteriorly divided into tertiles: T1<9.3, T2 ?9.3 - <9.9 and T3 ? 9.9.

Results:

138 patients were analysed, of whom 85.4% presented bilateral pneumonia.  At 3 months after discharge, chest CT scans were available in 132 patients from which 59% still presented abnormal findings and 23% presented impaired LFTs. Globally, the most frequent radiological finding was ground glass opacities (50%), followed by bronchial thickening (27.3%), reticular pattern (20.5%), consolidation (12.1%) and air bronchogram sign in 6.8% of patients.  Regarding ELF scores, differences were only observed in T3, with a reticular pattern as main radiological finding (p<0.005). Moreover, patients with both radiological and LFT impairment, presented higher levels of ELF compared with patients with only radiological or LFTs impairments, or no impairment (9.93 (0.77) vs 9.56 (0.82), 9.15 (1.1) and 9.33 (0.74), p<0.023).

Conclusion:

Patients with both radiological and LFTs alteration at 3 months after COVID-19 pneumonia, had higher levels of ELF. The ELF score might be useful to identify patients who will develop PF after COVID-19 pneumonia.