Why is COVID-19 especially impacting the African American population?

Underlying chronic medical conditions in African American population

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the ongoing coronavirus disease 2019 (COVID-19) pandemic, penetrates human cells through direct binding with its natural host receptor angiotensin-converting enzyme 2 (ACE2) at cell surface. An unbalanced activation of renin–angiotensin–aldosterone pathway has been found in patients with severe COVID-19 illness, which is also commonplace in patients with hypertension (HTN), type 2 diabetes mellitus (T2DM) and in the obese population with insulin-resistant states [1].

Obesity has been consolidated as an important risk factor for unfavourable progression in patients with SARS-CoV-2 infection, acting through multiple potential mechanisms [2–4]. In a first report, Qingxian et al. [5] pointed out that obesity increases the risk of developing severe pneumonia in COVID-19 patients. Price-Haywood et al. [6] retrospectively analysed the data of 3481 patients (31% African Americans –AA– and 65% white non-Hispanic) from Ochsner Health who tested positive for SARS-CoV-2 in Louisiana between 1 March 2020 and 11 April 2020. Importantly, the authors found that AA patients showed higher rates of obesity, T2DM, HTN and chronic kidney disease than white patients, and a total of 76.9% of hospitalized patients were AA. Additionally, AA were associated with obesity with increased probability of hospital admission, while 70.6% of COVID-19 patients who died were also AA. Nevertheless, AA race was not an independent predictor of worse outcomes. Shah et al. [7] analysed the data from 522 COVID-19 patients hospitalized in rural Georgia between 2 March 2020 and 6 May 2020 (87% of them were AA). These authors concluded that HTN and morbid obesity, as well as an age of 65 years or older and immunosuppression, were independent predictors of death.

A high body mass index (BMI) increases the risk of heart failure (HF) and/or cardiac dysfunction [8–10]. Chen et al. [11] showed that myocardial ACE2 expression is significantly increased in patients with HF, thus unravelling that HF patients may be more vulnerable to SARS-CoV-2 myocardial infection, and are also more prone to develop cardiac injury and to progress to critical illness and worse prognosis. Since SARS-CoV-2 penetration into the host cells is largely ACE2-dependent, the frequent observation of worse disease in patients with pre-exiting cardiovascular disease (CVD) may be explained by the increased ACE2 expression which accompanies this condition [12, 13].

AAs are disproportionately dying from COVID-19 compared to other ethnic populations [14]. More than 70% of COVID-19-related deaths in Louisiana and Alabama have involved AAs so far. Similarly, 70% of COVID-19 deaths in Chicago and 80% in Milwaukee County were AAs. A very similar exaggerated impact of COVID-19 on AAs has been reported in Philadelphia, Detroit and other cities.

The US Centers for Disease Control and Prevention (CDC) has recognized, based on currently available information and clinical expertise, that HTN, T2DM and severe obesity (BMI of 40 or higher) shall be considered common clinical risk factors for COVID-19 infection, and their presence has also been associated with worse prognosis and higher risk of death [15].

A higher prevalence of comorbid diseases, such as T2DM or obesity, increased baseline blood pressure levels and enhanced levels of physical inactivity, have been frequently reported in AAs [16], who are especially susceptible to HTN and its associated organ damage, thus ultimately fostering adverse CVD, cerebrovascular and renal outcomes. The prevalence of HTN in AAs in the US is among the highest worldwide, and seems to be continuously increasing. Moreover, lower HTN control rates are commonplace in AA populations compared with white people. On the other hand, patients with T2DM and metabolic syndrome might have up to 10-fold higher risk of death after developing COVID-19. Among non-Hispanic blacks aged 20 and older, 63% of men and 77% of women are overweight or obese, respectively.

Social determinants of health among African American population: racial disparity in the COVID-19 pandemic

Socioeconomic determinants, such as crowded housing (>1 person per room and lower social distancing scores) and insecurity, working in essential services (jobs requiring travel and public interaction, which do not permit working from home), and poor and/or inequitable access to health care, may all lead to certain comorbidities and even boost the spread of SARS-CoV-2. Likewise, there are more AA people in urban centres, being more likely to be affected in the first COVID-19 wave [17]. Importantly, AAs are also under significant psychological stress as consequence of income inequality, discrimination, violence and racism, which can also impair immunity and make them more vulnerable to SARS-CoV-2 infection. In effect, higher rates of COVID-19 cases and deaths have been reported in counties with higher number of AA residents, as well as higher prevalence of comorbidities, higher proportions of individuals aged 65 years or older, uninsured individuals, unemployed persons and higher air pollution [17]. In effect, this is not a novelty since other conditions, such as HIV [18] or cancer [19], show similar patterns.

Concluding remarks

The physiopathological susceptibility to severe COVID-19 infection in the AA population can hence be summarized as a multifactorial, “triple curse” process, involving the possible coexistence of HTN, obesity and/or overweight, and T2DM, although AA status itself may not be an independent reason for worse outcomes. The combination of these three co-morbidities would likely increase the vulnerability to COVID-19, potentially resulting in a “perfect storm,” ending up with dramatic consequences. Likewise, socioeconomic racial disparities also make AAs more vulnerable to SARS-CoV-2 infection. The AA population appears globally more vulnerable to severity of SARS-CoV-2 infection, thus displaying an enhanced risk of severe complications and needing specific precautions and reinforced preventing measures. We herein recommend that high-risk members of AA population with multiple comorbidities should strongly consider social distancing during the outbreak, managing to avoid exposure to suspected or confirmed COVID-19 cases, following their national guidance for vulnerable people living with chronic diseases. Strengthened education on the most frequent symptoms of SARS-CoV-2 infection shall also be pursued, so that an earlier diagnosis and a more aggressive treatment could be established to safeguard these especially vulnerable part of the population.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Fabian Sanchis-Gomar is supported by a postdoctoral contract granted by “Subprograma Atracció de Talent – Contractes Postdoctorals de la Universitat de València.”