2019-Coronavirus reached the French island of Reunion, which is marked by a very high prevalence of metabolic disorders such as obesity and type 2 diabetes mellitus (T2DM), in March 2020. The objective was to determine the metabolic factors associated with the severity of SARS-CoV-2 infection in Reunion Island.

This retrospective observational cohort study enrolled patients who were hospitalized on the island from March 11th, 2020 to August 4th, 2021. Severe Covid-19 was defined according to the WHO's definition, including deaths. A multilevel logistic model with the circulation period of the variants as a random effect was performed.

The median age of the 681 patients enrolled was 56 years [42–68] and 54% were men. Obese patients and patients who were both diabetic and obese had an increased risk of developing severe Covid-19: 2.64 [1.46;4.78] and 2.96 [1.47;5.93], aOR [CI95%] respectively. Diabetic inpatients did not when adjusting for individual characteristics and accounting the period of circulation of variants: 1.24 [0.68;2.24] (P = 0.471).

This study reveals an unexpected prominence of obesity on T2DM (without precision) in the development of severe Covid-19. Despite a high prevalence of T2DM, this finding may partially explain why Covid-19 did not have an even greater impact on the island. Further studies should also consider the treatment of diabetes, diabetic complications, glycemic imbalance or stratify by the novel subgroups of T2DM to better understand the link between T2DM and severe Covid-19 in the Reunionese population.