Visceral fat shows the strongest association with the need of intensive care in patients with COVID-19

Abstract

Background: Obesity was recently identified as a major risk factor for worse COVID-19 severity, especially among the young. The reason why its impact seems to be less pronounced in the elderly may be due to the concomitant presence of other comorbidities. However, all reports only focus on BMI, an indirect marker of body fat.

Aim: To explore the impact on COVID-19 severity of abdominal fat as a marker of body composition easily collected in patients undergoing a chest CT scan.

Methods: Patients included in this retrospective study were consecutively enrolled among those admitted to an Emergency Department in Rome, Italy, who tested positive for SARS-Cov-2 and underwent a chest CT scan in March 2020. Data were extracted from electronic medical records.

Results: 150 patients were included (64.7% male, mean age 64 ± 16 years). Visceral fat (VAT) was significantly higher in patients requiring intensive care (p = 0.032), together with age (p = 0.009), inflammation markers CRP and LDH (p < 0.0001, p = 0.003, respectively), and interstitial pneumonia severity as assessed by a Lung Severity Score (LSS) (p < 0.0001). Increasing age, lymphocytes, CRP, LDH, D-Dimer, LSS, total abdominal fat as well as VAT were found to have a significant univariate association with the need of intensive care. A multivariate analysis showed that LSS and VAT were independently associated with the need of intensive care (OR: 1.262; 95%CI: 1.0171-1.488; p = 0.005 and OR: 2.474; 95%CI: 1.017-6.019; p = 0.046, respectively).

Conclusions: VAT is a marker of worse clinical outcomes in patients with COVID-19. Given the exploratory nature of our study, further investigation is needed to confirm our findings and elucidate the mechanisms underlying such association.

Keywords: Body composition; Covid-19; Fat; Obesity; Risk factor; SARS-CoV-2.

Conflict of interest statement

Declaration of competing interest The authors of this manuscript have no conflicts of interest to disclose.

Copyright © 2020 Elsevier Inc. All rights reserved.

Figures

Fig. 1

Pulmonary involvement and fat analysis in a chest CT scan of a COVID-19 patient. (A–B) Ground glass opacities can be seen peripherally in the lower lobes, typical radiological pattern of COVID-19; (C) the first slice where lung bases are no more visible at the thoracoabdominal level where visceral adipose tissue (VAT), and total adipose tissue (TAT) are quantified: fat is identified in green. Subcutaneous adipose tissue was calculated by subtraction. (D) Histogram analysis of CT numbers, with a range of CT numbers classified as fat was −50 to −250.

Fig. 2

ICU admission requirement (%) per visceral adipose tissue area quartile (VAT Q) in the study population (A), stratified by age group (≤65, >65 years) (B), gender (C), and lung severity score (LSS) (high or low based on the population LSS median value) (D). Data are expressed as % and SD. P for interaction term, interaction of VAT accumulation and age (figure B), gender (figure C), and lung severity score (LSS) (figure D) on ICU admission, is from a synergy index (SI) analysis. The SI is the ratio of the combined effects and the individual effects. An SI of one means no interaction or perfect additivity. An SI of greater than one means positive interaction or more than additivity. An SI of less than one means negative interaction or less than additivity. SI ranges from zero to infinity (figures B, C and D). P for within group analysis is from a Chi-square test (figure A; subgroups for figures B, C and D).