Clinical Characteristics and Morbidity Associated With Coronavirus Disease 2019 in a Series of Patients in Metropolitan Detroit

IMPORTANCE In late December 2019, an outbreak caused by a novel severe acute respiratory syndrome coronavirus 2 emerged in Wuhan, China. Data on the clinical characteristics and outcomes of infected patients in urban communities in the US are limited. OBJECTIVES To describe the clinical characteristics and outcomes of patients with coronavirus disease 2019 (COVID-19) and to perform a comparative analysis of hospitalized and ambulatory patient populations. DESIGN, SETTING, AND PARTICIPANTS This study is a case series of 463 consecutive patients with COVID-19 evaluated at Henry Ford Health System in metropolitan Detroit, Michigan, from March 9 to March 27, 2020. Data analysis was performed from March to April 2020. EXPOSURE Laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection. MAIN OUTCOMES AND MEASURES Demographic data, underlying comorbidities, clinical presentation, complications, treatment, and outcomes were collected.


Introduction
An outbreak caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was reported in Wuhan, China in late December 2019. 1 Three months later, coronavirus disease 2019 (COVID- 19), the disease caused by SARS-CoV-2, was declared a pandemic by World Health Organization, and as of May 14, 2020, more than 4.3 million cases of COVID-19 and 297 000 deaths were reported. 2 Since it was first detected in Washington State on January 20, 2020, the US now leads the world with more than 1.39 million confirmed COVID-19 cases and 84 000 deaths. All 50 states have reported cases of COVID-19, with most states reporting community spread. 3 Early reports have suggested an incubation period of 2 to 14 days, with clinical presentations ranging from mild infection to severe disease to fatal illness. [3][4][5] The most commonly reported symptoms are cough, fever, and dyspnea. [6][7][8][9] Myalgia and gastrointestinal symptoms, including diarrhea and nausea or vomiting, are also common. 8 Recent reports 6,[9][10][11] suggest that approximately 14% to 29% of hospitalized patients with COVID-19 pneumonia require intensive care, primarily for respiratory support in the setting of hypoxic respiratory failure, with acute respiratory distress syndrome (ARDS) developing in 33% of hospitalized patients at a median time from symptom onset of 8 days. 9 In these reports, 6,8 critically ill patients were older, more likely to be male, and to have underlying comorbidities. The mortality rate ranged from 8.7% to 21% among those patients admitted with pneumonia. 6,[9][10][11] On March 10, 2020, the state of Michigan confirmed its first 2 cases of COVID-19, and in the days since, the case number has increased to 49 582 with 4787 (10%) deaths, amounting to the highest case fatality rate in the nation. 3 Metropolitan Detroit, which includes Oakland, Macomb, and Wayne counties, was at the epicenter of the outbreak, accounting for 80% of cases and 86% of deaths statewide. The city of Detroit accounted for almost one-third of all confirmed cases and deaths. 12 The objective of this study is to describe the clinical characteristics and outcomes of the first 463 patients with COVID-19 evaluated at the Henry Ford Health System (HFHS), a 5-hospital system that serves metropolitan Detroit, and to perform a comparative analysis of hospitalized and ambulatory patient populations.

Study Design and Participants
The HFHS institutional review board approved patient data review with waiver of consent because the data were deidentified. This is a case series that includes consecutive adult patients evaluated in HFHS from March 9, 2020 (date of first specimen tested), to March 27, 2020, and diagnosed with COVID-19. The HFHS is a comprehensive, integrated, health care organization that includes 5 hospitals and 9 emergency departments (EDs) in Southeast Michigan. Its 877-bed flagship hospital, Henry Ford Hospital, serves a large urban, mostly African American population in metropolitan Detroit. Patients were triaged on the basis of clinician judgment. All patients included in the study had SARS-CoV-2 infection confirmed by positive polymerase chain reaction testing of nasopharyngeal specimens. All clinical outcomes were monitored for 30 days.

Data Collection and Definitions
A trained team of physicians and research associates performed a retrospective review of the electronic health records to obtain data on a standardized data collection form. Demographic data, underlying comorbidities, symptoms and signs at presentation, complications, treatment, and outcomes were collected and evaluated. Race/ethnicity data were collected in electronic health records by self-report using standard classification. 13 Severe obesity (defined as body mass index [BMI] Ն40; BMI is calculated as weight in kilograms divided by height in meters squared) and ARDS were defined in accordance with the definition established by National Institute of Health 14 and Berlin Definition, 15 respectively. Acute kidney injury was diagnosed according to the Kidney Disease: Improving Global Outcomes definition. 16 Cardiac injury was characterized by the presence of serum levels of high-sensitivity cardiac troponin I above the 99th percentile upper reference limit.
Complications and treatment included acute kidney injury requiring renal replacement therapy, hypoxic respiratory failure and/or ARDS requiring invasive mechanical ventilation (IMV), and shock requiring vasopressor treatment. Outcomes included discharge from the ED, length of stay, discharge disposition, and 30-day readmission and mortality rates.

Laboratory and Radiographic Studies
Methods for laboratory confirmation of SARS-CoV-2 infection have been described elsewhere. 17 Influenza polymerase chain reaction testing was also performed for all patients. Routine blood examinations included daily complete blood count with differential, basic metabolic panel, liver function tests, ferritin, magnesium, C-reactive protein, lactate dehydrogenase, and creatine phosphokinase, in addition to high-sensitivity cardiac troponin I and D-dimer every 48 hours.
Furthermore, routine laboratory evaluation included interleukin-6 and disseminated intravascular coagulation panel when available for patients admitted to the intensive care unit (ICU). A chest radiograph and subsequent radiographs were obtained at baseline and as determined clinically by health care practitioners on case-by-case basis.

Statistical Analysis
Continuous variables were described as median (interquartile range [IQR]) or mean (SD), and categorical variables were described as frequency rates and percentages. The U test or t test was used for continuous variables, whereas the χ 2 or Fisher exact test was used for categorical variables.
Comparisons between cohorts were analyzed using univariable analysis. Multivariable logistic regression was performed to model the association of demographic characteristics and comorbidities with ventilator-dependent respiratory failure. Multivariable regression was also performed to model the association of demographic characteristics and comorbidities with the need for ICU care at any time during the hospitalization. Race (African American or non-African American) was included in these models because of the high proportion of African American patients in Detroit.
Demographic characteristics or comorbidities in which univariable analysis yielded P < .10 were included. Finally, multivariable logistic regression analysis of the associations of age older than 60 years, African American race, and sex with mortality was performed. At the time of analysis, mortality data were complete to 30 days after the initial encounter. We did not perform a formal sample size calculation for the study because the primary objective was to describe the characteristics of the initial surge of patients positive for SARS-CoV-2 within our health system. A 2-sided α < .05 was considered statistically significant. Odds ratios (ORs) with 95% CIs were reported for all models.
Statistical analyses were performed using SAS statistical software version 9.4 (SAS Institute). Data analysis was performed from March to April 2020.
the study because of a lack of demographic and baseline data.

Discussion
This study describes the demographic characteristics and clinical presentation of the initial 463 patients with COVID-19 evaluated in the HFHS, a multicenter academic institution in metropolitan Detroit. This study provides additional insight into the clinical presentation and outcomes of COVID-19 in an urban setting.
Compared with previous reports, most of our patients were African American and required hospitalization. 6,8,10 However, our findings support the observations of earlier studies, which found a high percentage of hospitalized patients of advanced age with preexisting conditions, hypertension being the most common. 6,8,9,18 COVID-19 rapidly spread throughout the state of Michigan and has disproportionately affected the African American population, who have high rates of comorbid conditions and mean BMI of 30. 19,20 As of May 14, 2020, African American patients accounted for 32% of cases and 41% of deaths despite composing only 14% of the state's population. 12,21 This is in line with what has been described in other states. 22 For example, in Louisiana, African American residents make up 32% of the state population, but accounted for more than 56% of COVID-19 deaths as of May 14, 2020. 23 Factors such as lower wage positions and employment in critical infrastructure jobs, higher rates of poverty, lack of access to a personal vehicle and reliance on public transportation, and unstable or crowded housing conditions make preventive strategies such as social distancing and self-isolation or quarantine difficult to maintain. 24 In Michigan, 27% of African American residents lived in poverty compared with 11% of white residents in 2019. 25 These social determinants of health result in lack of health insurance and access to care, which may put patients at a disproportionately greater risk of acquiring infection and higher rates of complications from COVID-19.
Interestingly, more than one-half of cases and hospitalizations occurred among women, in contrast to previous reports. 6,8,9,18 Women represent 51% and 53% of the Michigan and Detroit populations, respectively. 21,26 In addition, they have a lower labor force participation rate (55%) and higher poverty rate (15% vs 12%) compared with their male counterparts (70%), according to the most recent data. 25 Poverty can negatively affect family structure and increase health risks, all of which may have contributed to the higher infection rates in women.
The spectrum of disease described in our study is similar to those from the Centers for Disease

Control and Prevention's COVID-19-Associated Hospitalization Surveillance Network, the New York
City area, and China. 5,7,9,27 In the initial reports from Wuhan, China, during the early stages of the pandemic, 24  and up to 20% in reports from China. 6,9,11,24 In the multivariable analysis, race was not associated with ICU admission or the need for IMV; however, male sex, severe obesity, and CKD were associated  with need for ICU level care and IMV. A notable characteristic in our cohort was the prevalence of obesity; the mean BMI of hospitalized patients was 33.6, with 26% of severely obese patients requiring ICU. Severe obesity was independently associated with the need for mechanical ventilation (OR, 3.2; 95% CI, 1.7-6.0; P < .001). The association between obesity and need for IMV has been previously reported in patients with COVID-19. 25 In a retrospective analysis 28 of 124 patients in the ICU, almost one-half had BMI greater than 30, including 15% with BMI greater than or equal to 40.
The mean BMI was 31 (range, 27.3-37.5) in patients requiring IMV compared with 27 (range, 25.3-30.8) in those who did not (P < .001). 28 Moreover, in that study, BMI greater than 35 was independently associated with the need for IMV (OR, 7.36; 95% CI, 1.63-33.14; P = .02). 28 The rate of complications, including acute kidney injury, hypoxic respiratory failure, and need for IMV, was higher and the length of stay was longer in our patient population than what was recently reported in New York City 6 ; however, the rate of readmission was less than 10% in both cohorts. Overall mortality was in line with what has been reported in the US. 6,8,10 Similarly, ICU mortality was higher than GPU mortality. 10 Male sex and age older than 60 years were significantly associated with mortality but race was not.

Limitations
This study has a few limitations. It was conducted a single large health system in Southeast Michigan.
In addition, this case series has no control group, and the findings may not be generalizable to other populations.

Conclusions
In this study of patients infected with SARS-CoV-2 in the metropolitan Detroit area, 76.7% of the patients who were infected were hospitalized and most of these patients were African American. The high prevalence of comorbidities and severe obesity in the population likely contributed to the disparities in morbidity associated with COVID-19.