Abstract: Open access Original research Elie Mulhem ‍ ‍, Andrew Oleszkowicz, David Lick To cite: Mulhem E, Oleszkowicz A, Lick D. 3219 hospitalised patients with COVID-19 in Southeast Michigan: a retrospective case cohort study. BMJ Open 2021;11:e042042. doi:10.1136/ bmjopen-2020-042042 ►► Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online (http://​dx.​doi.o​ rg/​10.​1136/​ bmjopen-​2020-​042042). Received 23 June 2020 Revised 10 November 2020 Accepted 16 March 2021 © Author(s) (or their employer(s)) 2021. Re-­use permitted under CC BY-­NC. No commercial re-­use. See rights and permissions. Published by BMJ. Department of Family Medicine and Community Health, Oakland University William Beaumont School of Medicine, Rochester, Michigan, USA Correspondence to Dr Elie Mulhem; ​elie.​mulhem@b​ eaumont.​edu ABSTRACT Objective To report the clinical characteristics of patients hospitalised with COVID-19 in Southeast Michigan. Design Retrospective cohort study. Setting Eight hospitals in Southeast Michigan. Participants 3219 hospitalised patients with a positive SARS-­CoV-2 infection by nasopharyngeal PCR test from 13 March 2020 until 29 April 2020. Main outcomes measures Outcomes were discharge from the hospital or in-­hospital death. Examined predictors included patient demographics, chronic diseases, home medications, mechanical ventilation, in-­hospital medications and timeframe of hospital admission. Multivariable logistic regression was conducted to identify risk factors for in-­hospital mortality. Results During the study period, 3219 (90.4%) patients were discharged or died in the hospital. The median age was 65.2 (IQR 52.6–77.2) years, the median length of stay in the hospital was 6.0 (IQR 3.2–10.1) days, and 51% were female. Hypertension was the most common chronic disease, occurring in 2386 (74.1%) patients. Overall mortality rate was 16.0%. Blacks represented 52.3% of patients and had a mortality rate of 13.5%. Mortality was highest at 18.5% in the prepeak hospital COVID-19 volume, decreasing to 15.3% during the peak period and to 10.8% in the postpeak period. Multivariable regression showed increasing odds of in-­hospital death associated with older age (OR 1.04, 95% CI 1.03 to 1.05, p<0.001) for every increase in 1 year of age and being male (OR 1.47, 95% CI 1.21 to 1.81, p<0.001). Certain chronic diseases increased the odds of in-­hospital mortality, especially chronic kidney disease. Administration of vitamin C, corticosteroids and therapeutic heparin in the hospital was associated with higher odds of death. Conclusion In-­hospital mortality was highest in early admissions and improved as our experience in treating patients with COVID-19 increased. Blacks were more likely to get admitted to the hospital and to receive mechanical ventilation, but less likely to die in the hospital than whites. COVID-19 was first reported as an outbreak of pneumonia of unknown cause in Wuhan, China in December 2019.1 The virus responsible was subsequently named SARS-­ CoV-2. The first confirmed case in the USA was reported on 31 January 2020, and the first case in Michigan was reported on 10 March 2020.2 As of 1 June 2020, 57 532 cases have Strengths and limitations of this study ►► This is the largest study to date to describe the hospitalised patient population with SARS-­CoV-2 in Southeast Michigan. ►► The study population represents a large and..