Combined association of obesity and other cardiometabolic diseases with severe COVID-19 outcomes: a nationwide cross-sectional study of 21,773 Brazilian adult and elderly inpatients
Authors: Silva Natanael J , Ribeiro-Silva Rita C , Ferreira Andrêa JF , Teixeira Camila SS , Rocha Aline S , Alves Flávia Jôse O , Falcão Ila R , Pinto Elizabete J , Antônio ST Santos Carlos , Fiaccone Rosemeire L , Ichihara Maria Yury T , Paixão Enny S , Barreto Mauricio L 
Published: May 2021

Objectives

To investigate the combined association of obesity, diabetes mellitus (DM), and cardiovascular disease (CVD) with severe COVID-19 outcomes in adult and elderly inpatients.

Design

Cross-sectional study based on registry data from Brazil’s influenza surveillance system.

Setting

Public and private hospitals across Brazil.

Participants

Eligible population included 21,942 inpatients aged ≥20 years with positive RT-PCR test for SARS-CoV-2 until Jun 9th, 2020.

Main outcome measures

Severe COVID-19 outcomes were non-invasive and invasive mechanical ventilation use, ICU admission, and death. Multivariate analyses were conducted separately for adults (20-59 years) and elders (≥60 years) to test the combined association of obesity (without and with DM and/or CVD) and degrees of obesity with each outcome.

Results

A sample of 8,848 adults and 12,925 elders were included. Among adults, obesity with DM and/or CVD showed higher prevalence of invasive (PR 3.76, 95%CI 2.82-5.01) and non-invasive mechanical ventilation use (2.06, 1.58-2.69), ICU admission (1.60, 1.40-1.83), and death (1.79, 1.45-2.21) compared with the group without obesity, DM, and CVD. In elders, obesity alone (without DM and CVD) had the highest prevalence of ICU admission (1.40, 1.07-1.82) and death (1.67, 1.00-2.80). In both age groups, obesity alone and combined with DM and/or CVD showed higher prevalence in all outcomes than DM and/or CVD. A dose-response association was observed between obesity and death in adults: class I 1.32 (1.05-1.66), class II 1.41 (1.06-1.87), and class III 1.77 (1.35-2.33).

Conclusions

The combined association of obesity, diabetes, and/or CVD with severe COVID-19 outcomes may be stronger in adults than in elders. Obesity alone and combined with DM and/or CVD had more impact on the risk of COVID-19 severity than DM and/or CVD in both age groups. The study also supports an independent relationship of obesity with severe outcomes, including a dose-response association between degrees of obesity and death in adults.

Article summary

Strengths and limitations of this study:

This is the first study that describes the independent and combined relationship of obesity with COVID-19 severity in Brazil, one of the biggest epicenters of the pandemic worldwide.

The study was based on registry data of a large nationwide sample of patients admitted, due to severe SARS-CoV-2 infection, to public and private hospitals across the country.

The large sample size and data availability allowed us to analyze the combined association of obesity, diabetes and cardiovascular disease with severe COVID-19 outcomes, separately by age groups and controlled by important confounding variables, e.g. underlying comorbidities.

The cross-sectional study design does not allow causal inference, and generalization of results must be cautious since only hospitalized cases of severe COVID-19 were included.

As the study used routinely collected data, which has not been designed primarily for research purposes, it may bring well-known limitations related to missing, underestimation, and potential misclassification.