The association of decreased thoracic muscle mass with unfavourable outcomes in lung transplant patients with COVID-19: a retrospective cohort study

Coronavirus disease 2019 (COVID-19) has become an important issue in immunocompromised patients owing to the high transmissibility of severe acute respiratory syndrome coronavirus 2. Sarcopenia in lung transplant patients is associated with a poor prognosis, and patients who have undergone lung transplant are more vulnerable to COVID-19. This study aimed to investigate the association of sarcopenia with clinical outcomes in lung transplant patients with COVID-19 and the risk factors for sarcopenia following COVID-19 in lung transplant patients. We performed a retrospective cohort study of lung transplant patients with COVID-19. Sarcopenia was defined as being within the lower 25% of the thoracic muscle index based on cross-sectional area measurements at the fourth vertebra using computed tomography (CT). Multivariable logistic analysis was conducted to identify factors associated with sarcopenia in lung transplant patients with COVID-19. Of the 445 patients who received follow-up care after lung transplantation, 81 were diagnosed with COVID-19. Among patients within three years of lung transplantation, the sarcopenia group had a significantly higher rate of hospitalisation (100.0% vs. 46.9%, P = 0.006) and oxygen demand (63.6% vs. 18.8%, P = 0.016) than the non-sarcopenia group. Body mass index before COVID-19 (odds ratio [OR], 0.77; confidence interval [CI], 0.58–0.96; P = 0.040) and serum albumin (OR, 0.12; CI, 0.01–0.79; P = 0.047) were significantly associated with sarcopenia after COVID-19. Sarcopenia is associated with poor COVID-19 outcomes in patients within three years after lung transplantation. Assessment and intervention for sarcopenia are required to improve the prognosis of patients undergoing lung transplantation for COVID-19.