ICU predictive factors of fibrotic changes following COVID-19 related ARDS: a RECOVIDS substudy

Pulmonary fibrotic changes (FC) following COVID-19-related ARDS represent a significant concern due to the potential respiratory complications. The identification of early predictive factors for FC and the development of predictive tools are needed to optimize patient management and outcomes.

This observational prospective multicentre study is a substudy of the RECOVIDS study and included 32 centres in France and Belgium. COVID-19 ARDS survivors were included if they met the Berlin ARDS criteria or if they received high flow oxygen therapy (flow ≥ 50 L/min and FiO₂ ≥ 50%). Exclusion criteria were non-attendance at follow-up 6 ± 1 months after ICU discharge, lack of baseline or follow-up chest CT, and history of interstitial lung disease. The primary endpoint was presence of FC at follow-up CT. The secondary outcome was to identify predominant radiological patterns.

Among 555 patients included in the RECOVIDS study, 440 were analysed, of whom 162 (36.8%) had FC at follow-up. Predictive factors for FC included older age, body mass index < 30, Charlson comorbidity index ≥ 1, invasive mechanical ventilation, early signs of FC, and greater lung involvement on baseline CT. The nomogram for predicting pulmonary FC yielded an AUC of 80.6% (95%CI (76.4-84.8)). Late organizing pneumonia was the most common pattern overall and 30 (18.5%) of the 162 patients with FC presented mainly anterior fibrosis compatible with post ventilatory changes.

In this large cohort of COVID-19 ARDS survivors, 36.8% exhibited FC at 6 months post-ICU discharge. The key predictors identified here could guide therapeutic and follow-up strategies.