CHEST CT BODY COMPOSITION CHANGES at 3 and 6 MONTHS after SEVERE COVID-19 PNEUMONIA

ABSTRACT

Background: Muscle and fat mass loss as a consequence of protein catabolism and prolonged immobilization is frequent in critically ill patients. Post-COVID acute sarcopenia may be due also to inflammaging for the strong inflammatory reaction. The study aims were to describe changes in chest CT body composition parameters from baseline to follow-up CT scan in severe COVID-19 survivors, and to evaluate the impact of COVID-19 inflammatory burden on these changes. Methods: Baseline (t0), 2-3 months (t1) and 6-7 months (t2) follow-up CT scan of severe COVID-19 pneumonia survivors were retrospectively reviewed to measure pectoralis muscle area (PMA) and density (PMD), liver-to-spleen ratio (LSR), and total, visceral, and intermuscular adipose tissue areas (TAT, VAT and IMAT) at T7-T8 vertebrae. C-reactive protein (CRP) curve integral was used to describe COVID-19 inflammatory burden, and its impact on body composition changes was evaluated in multivariable linear regression models adjusted for age, sex, and baseline TAT (index of general adiposity). Results: At follow-up a decrease in mean PMA and in all mean body fat areas was registered, faster from t0 to t1, and slower from t1 to t2, with the exception of PMD, which increased (i.e. intramuscular fat decreased) only from t1 to t2 (Table). Mean VAT decrease was more conspicuous than mean TAT decrease. In models adjusted for age, sex, and baseline TAT, increasing CRP integral was significantly associated with higher PMA reduction (p=0,017 for delta t2-t0) and lower PMD increase (p=0.01 for delta t2-t0), higher LSR increase (i.e. higher steatosis decrease) (p<0.0001 for delta t1-t0, n.s. for delta t2-t0), and higher VAT decrease (p=0.035 for delta t2-t0), but not with TAT decrease. These associations were stronger in patients with higher VAT and lower LSR at baseline. Conclusion: Muscle and fat loss after COVID-19 is faster in the first months, but slowly continues till 6-7 months. Fat loss is more apparent in visceral compartments. Inflammatory burden is associated with the degree of muscle and visceral/liver fat loss.