Diaphragm thickness on computed tomography for nutritional assessment and hospital stay prediction in critical COVID-19

Background and Objectives: To evaluate the significance of diaphragm thickness (DT) in assessing the nutritional status and predicting the length of hospital stay (LOS) of patients with COVID-19. Methods and Study Design: The data of 212 patients with severe and critical COVID-19 in Wuhan, China, were retrospectively analyzed. Computed tomography (CT)-obtained DT was measured in cross-sectional images of the mediastinal window at the level of the outlet of the celiac trunk at admission and at 2 weeks, then the rate of change in DT(RCDT) at 2 weeks was calculated. Nutritional risk and malnutrition were evaluated at admission. Results: A total of 91 patients were involved in the study. The mean DT was 3.06 +/- 0.58 mm (3.15 +/- 0.63 mm in male and 2.93 +/- 0.50 mm in female). DT was significantly negatively correlated with malnutrition based on Global Leadership Initiative on Malnutrition (GLIM) criteria (r=-0.324, p=0.002), Nutritional Risk Screening 2002 (NRS-2002) score (r=-0.364, p=0.000) and the Malnutrition Universal Screening Tool (MUST) score (r=-0.326, p=0.002) at admission. For the prediction of LOS >= 4 weeks in patients with COVID-19, the area under the ROC curve (AUC) of the RCDT at 2 weeks was 0.772, while the AUCs of DT, NRS-2002, MUST and Nutrition Risk in Critically Ill scores at admission were 0.751, 0.676, 0.638 and 0.699 respectively. According to the model of multiple linear regression analysis, the DT at admission (beta=-0.377, p=0.000), RCDT at 2 weeks (beta =-0.323, p=0.001), and mechanical ventilation (beta=0.192, p=0.031) were independent risk factors contributed to LOS. Conclusions: CT-obtained DT can be used as a dynamic assessment tool for evaluating the nutritional status of patients in isolation wards for COVID-19.