Abstract: (2021) 13:76 Tamura et al. Diabetol Metab Syndr https://doi.org/10.1186/s13098-021-00695-8 Diabetology & Metabolic Syndrome Open Access RESEARCH Outcome and death risk of diabetes patients with Covid‑19 receiving pre‑hospital and in‑hospital metformin therapies Rodrigo Esaki Tamura1,3, Said Muhammad Said2,4, Leticia Mussin de Freitas1 and Ileana Gabriela Sanchez Rubio1,2,3* Abstract Background: COVID-19 has stroke Brazil harshly, deaths by COVID-19 in Brazil represent almost 13% of the total deaths by COVID-19 in the world, even though Brazilian population represents only 2.6% of the world population. Our aim in this study was to evaluate death and intubation outcomes and risk factors associated with COVID-19, and treatment options focusing on diabetes patients and the use of metformin pre-admission and during hospitalization. Methods: In this Brazilian single-center study we evaluated 1170 patients hospitalized due to COVID-19. Diabetes patients (n = 188) were divided based on their use of pre-hospital and in-hospital metformin (non-met-group and met-group). Results: In the total cohort most comorbidities were risk factors for orotracheal intubation and death. The use of chloroquine/hydroxychloroquine was significantly associated with increased death and intubation risk in uni- and multivariate analysis. Diabetes patients showed worst clinical feature compared with non-diabetes patients. In-hospital non-met-group had increased mortality (20.5%) compared to met-group (3.5%) (p = 0.0002) and univariable cox proportion hazard regression indicated in-hospital metformin reduced mortality (HR = 0.325, p = 0.035). Patients that used pre-hospital metformin showed lower severity parameters at hospital admission. (met-group: 2.45 ± 2.5; nonmet-group: 4.25 ± 3.4). In all the groups older patients showed more severe clinical conditions and high risk of death and intubation. Conclusion: Even though this is a single-center study, results from other reports have shown a similar trend, indicating that patients that used metformin during hospitalization have a better prognosis and reduced risk of death. Keywords: COVID-19, Diabetes, Metformin, Brazil, Survival Background The COVID-19 pandemic is caused by SARS-CoV-2, a member of the Betacoronavirus genus of the Nidovirales order, its single stranded positive polarity RNA encodes non-structural and structural proteins, one important structural protein is the Spike, which mediates *Correspondence: ilerubio@gmail.com; ileana.rubio@unifesp.br 1 Department of Biological Sciences, Federal University of São Paulo, Rua Pedro de Toledo 669, 11º Andar, Diadema, SP, Brazil Full list of author information is available at the end of the article recognition of the ACE2 cell receptor. The non-structural proteins play pivotal role in cell regulation, that impacts host response to viral infection [1]. Data from the World Health Organization (WHO) points to over 178 million confirmed cases and 3,864,180 deaths until June, 21st 2021 (https://​covid​19.​who.​int/). Deaths by COVID-19 in Brazil has reached the number of 501,825 on June, 21st 2021 (https://​covid.​saude.​gov.​br/). Diabetes is one of the main risk factors for COVID19, promoting a harmful pro-inflammatory state [2]. © The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate..