There is a Relationship Between Obesity and Coronavirus Disease 2019 but More Information is Needed

Abstract

To the Editor: We read with particular interest your comments in Obesity regarding the coronavirus disease 2019 (COVID-19) epidemic ((1)) and a related manuscript by Simonnet et al. ((2)). Resolution of the specific relationship between obesity and COVID-19, two existing public health epidemics, is critically needed to potentially prevent health systems worldwide from being overburdened. Few studies describing COVID-19 with rates of obesity exist, and most are based on heterogenous populations (Table 1) ((2-9)). In cohort studies of COVID-19, obesity rates are generally reported as no higher than population-based estimates; in contrast, subgroups of patients with critical illness (e.g., intensive care unit [ICU] patients) report higher prevalence rates of obesity. In Italy, no official data have been released to evaluate the prevalence of obesity in COVID-19 patients. A recent Italian report ((10)) failed to mention obesity as a comorbidity in admitted ICU patients with COVID-19, despite the higher rates of obesity in severe disease (including ICU admission) in non-Italian studies (Table 1). Although correlation does not imply a causal relationship, as other factors may indeed play a role in the heterogeneity of the sampled population, the incidence of COVID-19 in each Italian region is surprisingly inversely related to the regional prevalence of obesity (r = −0.76; P < 0.001) (Figure 1). Yet Italian data demonstrated high obesity rates (~71%) only among younger patients (<40 years) dying of COVID-19 in this small subgroup of 49 patients. Such data suggest that in Italy, obesity may have a greater impact at a younger age, which is consistent with data from ICU cohorts without COVID-19. In fact, it also was reported ((5)) that the risk of ICU admission for patients with obesity is higher at younger ages (<60 years old). We cautiously speculate that the higher obesity rates (>75%) in ICU-based patients with COVID-19 as reported by Simonnet et al. ((2)) may depend on the relatively young age of their cohort (median age of 60 years). These authors also observed an increased risk of mechanical ventilation in patients with class II obesity. Rates of critical illness in patients with COVID-19 and obesity are higher than those reported for ICU patients with obesity (~20%) ((11)). Although lower mortality rates have been reported in patients with BMI ≥ 25 kg/m2 in ICU settings ((11, 12)), additional data are lacking in ICU-based COVID-19 with obesity. Despite many limitations, data reported in Table 1 distinguish among obesity, diabetes, and hypertension, which further supports the importance of obesity in this illness. In conclusion, obesity strongly impacts the severity of COVID-19, yet it behooves clinicians and researchers to recognize the heterogenous nature of the existing cohort data. This study furthers our understanding of the obesity/COVID-19 relationship. There are important, unresolved questions related to the impact of body composition (fat/fat-free muscle), relevant coexisting comorbid conditions, severity of disease, and predictors of important outcomes such as hospitalization and mortality in this population. The authors declared no conflict of interest.

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