Baseline Demographics and Clinical Characteristics Among 3471 US Patients Hospitalized with COVID-19 and Pulmonary Involvement: A Retrospective Study

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The global coronavirus disease 2019 (COVID-19) pandemic began in Wuhan, China, and quickly spread internationally [1]. As of July 28, 2020, there were over 4.3 million confirmed cases of COVID-19 in the US and over 148,000 deaths [2]. COVID-19 can present as a range of symptoms, from mild to critical; lower pulmonary involvement, including severe pneumonia, dyspnea, or blood oxygen saturation ≤ 93%, among other potential symptoms, is often associated with severe and critical cases [3].

Understanding the baseline characteristics of patients hospitalized with COVID-19 illness is essential for effectively targeting clinical care and allocating resources. Two large studies of patients hospitalized with COVID-19 illness in New York observed that the majority of patients were male and the most common comorbidities were hypertension, obesity, and diabetes [4, 5]. In comparison, a study of patients hospitalized with COVID-19 in Louisiana reported that the majority of patients were female and 70% were Black non-Hispanic; in that study, increased odds of hospital admission were associated with Black race, increasing age, higher Charlson Comorbidity Index (CCI), public insurance, residence in a low-income area, and obesity [6]. These studies demonstrate that patients from one state may not be representative of patients throughout the US and that studies across a variety of geographic regions are needed to specifically tailor clinical responses to COVID-19.

The objective of this study was to examine baseline demographics and clinical characteristics of US patients hospitalized with COVID-19 and pulmonary involvement. This study utilized the IBM Explorys^® US electronic health records (EHR) database, which includes a racially diverse group of patients primarily from the South and Midwest. Patients in the database with COVID-19 and pulmonary involvement from December 1, 2019, to May 20, 2020, were included; patients were examined overall and stratified by sex, age, race, and geographic region.

This study examined baseline demographics and clinical characteristics among US patients primarily from the South and Midwest—regions with limited data on patients with COVID-19—who were hospitalized with COVID-19 illness and pulmonary involvement. Overall, 81.6% of patients were from the South and 16.8% from the Midwest. Two highly represented groups were female (51.2%) and African American (55.0%) patients. The mean (SD) age was 63.5 (16.3) years. Hypertension, diabetes, hyperlipidemia, and obesity were the most common comorbidities. Preadmission pulmonary symptoms were also examined, and the most common were cough and dyspnea.

The most prevalent comorbidities observed were the same as those reported after analysis of EHR data of 5700 patients hospitalized with COVID-19 from the New York City area, with the addition of hyperlipidemia, although they were present in a lower proportion of patients in this study vs. the New York study (hypertension, 27.7% vs. 56.6%; diabetes, 17.3% vs. 33.8%; obesity, 9.7% vs. 41.7%, respectively) [4]. A retrospective cohort study of patients diagnosed with COVID-19 in Louisiana, including nonhospitalized and hospitalized patients, reported similar rates of hypertension and diabetes but a higher rate of obesity than the present study [6]. Diagnoses for obesity, defined by the US Centers for Disease Control and Prevention as BMI ≥ 30, may be underreported in the EHR database used in this study, as both the mean and median BMI were > 30 for the overall population [9].

Analyses by region demonstrated that, when compared with patients from the South (primarily from Louisiana, Maryland, and the District of Columbia), patients from the Midwest (primarily from Ohio) had higher mean CCI and increased prevalence of hypertension, diabetes, hyperlipidemia, and obesity. In comparison, according to a 2019 report on obesity in the US, Ohio has higher rates of obesity, hypertension, and diabetes than Maryland and the District of Columbia but lower rates than Louisiana [10]. There were differences in insurance plan type between regions; however, no conclusions can be drawn because these data were missing for the majority of patients.

Although data on the role of race in COVID-19 illness and outcomes are limited and complex, several studies have demonstrated that there may be increased risk of infection and worse clinical outcomes among Black patients. The potential underlying reasons for these findings are important to consider and may include socioeconomic and health inequalities, resource deprivation, and pathophysiologic differences in response to infection, but further research is needed [6, 11‐14].

In this study, 55.0% of patients hospitalized with COVID-19 were African American. African American patients are not overrepresented in the Explorys database overall: patients in the South are 16.0% African American and 43.0% White, and patients in the Midwest are 10.9% and 62.9%, respectively. This reflects the US population, which according to the latest Census data is 13.4% Black or African American and 60.4% White (not Hispanic or Latinx) [15].

In the present study, among patients from the South, 60.8% were African American and 27.2% were White, and in the Midwest, 31.0% were African American and 59.5% were White. Increased rates of infection observed in the African American population in this study might be due to the tendency of the COVID-19 epidemic to be more severe in certain geographic areas—in this case, in areas with a high prevalence of African Americans. It also may be due to the disease attacking poorer Americans who have essential jobs and cannot isolate or socially distance. In this study, African American patients were younger and a higher proportion were female compared with White patients; these findings are similar to those of a study of 3626 patients in Louisiana, the majority of whom self-identified as Black non-Hispanic [6]. The mean CCI was higher in African American patients than White patients, although the difference was not statistically significant. In the Louisiana study, a higher mean CCI was also observed in Black patients than White patients hospitalized with COVID-19, and racial differences in CCI have been reported among the general US population [6, 16]. The present study also observed that the proportions of African American patients with diabetes and obesity were higher than those of White patients, which is a finding similar to that in the Louisiana cohort, although that was regardless of hospitalization status. Differences in insurance plan type were observed when patients were stratified by race; however, no conclusions can be drawn because, for the majority of patients, these data were missing.

The implications of the differences in baseline characteristics between Black patients and White patients hospitalized with COVID-19 and pulmonary involvement are not yet clear. However, it appears that obesity and diabetes are risk factors for complications in COVID-19 across all races [4‐6]. Several large studies have found the prevalence of obesity and diabetes in US patients with COVID-19 to be higher than that of the general US adult population, in which 39.5% of adults are obese and 10.2% have diagnosed diabetes [4‐6, 10, 17]. The prevalence of these health conditions varies among demographic groups, and there are many complex factors underlying these differences, including historical, socioeconomic, and policy inequities that exert systemic effects on daily life that play many roles in health [10, 17]. In a study of > 10,000 COVID-19-related deaths in England, a multivariable model that adjusted for underlying health conditions found that greater deprivation—a socioeconomic measure including income, employment, education, health, crime, and living environment—was associated with increased risk of death and suggests that societal factors likely play a key role in COVID-19 outcomes [14]. Importantly, further studies are needed on the underlying reasons for racial disparities in COVID-19 and other health emergencies to more robustly explain these patterns, mitigate any potential misinterpretations of analyses based on race, and improve outcomes for patients [12‐14].

This study has several limitations related to retrospective analysis of EHR data. Medications that patients were taking but that were not prescribed in the baseline period or were prescribed by a healthcare provider outside of the systems that contribute to Explorys were not captured. Patients were also presumed to have filled and taken medications as prescribed, but this cannot be confirmed. Diagnoses that were made by providers outside of the systems that contribute to Explorys were not captured, and conditions for which patients did not seek care were not included. Results may not be generalizable to the US population as a whole, as a majority of the patients were from the South and Midwest. Selection for those populations was not intended, as the selection criteria included nationally used ICD codes; these trends reflect the geographic distribution of the Explorys database and may reflect the nature of the COVID-19 outbreak. These large cohorts of Southern and Midwestern patients are also a strength of this study, because currently the data on baseline characteristics of patients with COVID-19 in these regions are limited. Descriptive statistics were used, and additional analyses are needed to adjust for potential confounding factors. Despite these limitations, this study provides important information from a large real-world population of US patients hospitalized with COVID-19 and pulmonary symptoms.

Among US patients hospitalized with COVID-19 and pulmonary involvement primarily from the South and Midwest, the most common comorbidities were hypertension, diabetes, hyperlipidemia, and obesity. The higher represented demographic groups included patients from the South, African American patients, and female patients. Compared with White patients, African American patients were younger, with higher mean BMI, higher prevalence of concurrent diabetes, and lower prevalence of COPD and smoking/tobacco use. Although this study confirms trends observed elsewhere, it is important to view these data in the context of the complex underlying reasons for racial disparities in COVID-19; further research is needed to understand the implications of these observations.