Race is most important predictor of SARS-CoV-2 infection, says study

Race or ethnicity strongly predicts the risk of infection with SARS-CoV-2, the causative agent of COVID-19, according to a recent study. Following infection, race correlates with an increased hospitalization risk but not mortality.

“Race/ethnicity was the most important factor in a patient's likelihood of becoming infected with SARS-CoV-2,” the researchers said. “Compared with White persons, the other racial groups had increased incidence of SARS-CoV-2 infection that persisted after controlling for age, sex, neighbourhood deprivation index (NDI), and pre-existing comorbidity burden.”

A retrospective cohort study was conducted from 1 February 2020 to 31 May 2020, including 3,481,716 adult health plan members in an integrated healthcare delivery system in Northern California, US. Among eligible members, 42.0 percent were White, 6.4 percent African American, 19.9 percent Hispanic, and 18.6 percent Asian, while 13.0 percent were of other or unknown race.

A total of 91,212 members (2.6 percent) were screened for SARS-CoV-2 infections, of whom 3,686 turned out positive (overall incidence, 105.9 per 100,000 persons; by racial group: White, 55.1; African American, 123.1; Hispanic, 219.6; Asian, 111.7; other/unknown, 79.3). [Ann Intern Med 2021;doi:10.7326/M20-6979]

African Americans showed the highest unadjusted testing and mortality rates, while White persons had the lowest testing rates; those with other or unknown race had the lowest mortality rates.

Adjusted testing rates among non-White persons were slightly higher than those among White persons, but infections rates were also significantly greater (African Americans: adjusted odds ratio [aOR], 2.01 (95 percent confidence interval [CI], 1.75–2.31; Hispanics: aOR, 3.93, 95 percent CI, 3.59–4.30; Asians: aOR, 2.19, 95 percent CI, 1.98–2.42; other race: aOR, 1.57, 95 percent CI, 1.38–1.78). In geographic analyses, infections were found to cluster in areas with higher proportions of non-White persons.

Adjusted hospitalization rates in comparison to White persons were as follows: African Americans (1.47, 95 percent CI, 1.03–2.09); Hispanics (1.42, 95 percent CI, 1.11–1.82); Asians (1.47, 95 percent CI, 1.13–1.92); other race (1.03, 95 percent CI, 0.72–1.46). In adjusted analyses, no racial differences were noted in inpatient or total mortality during the study period.

In terms of testing, comorbid conditions had the “greatest relative contribution to model explanatory power” (77.9 percent), while race only accounted for 8.1 percent. Race was most predictive of SARS-CoV-2 infection (80.3 percent). For other outcomes, age was most important, while race only contributed 4.5 percent for hospitalization, 12.8 percent for admission illness severity, 2.3 percent for in-hospital death, and 0.4 percent for any death.

“In our cohort, non-White persons tended to be younger than White persons. However, non-White persons had elevated rates for other risk factors for infection (comorbid conditions and neighbourhood deprivation),” the researchers said.

“Many factors may contribute to comorbidity and intrinsic risk, including the totality of ways in which societies foster racial discrimination, through mutually reinforcing inequitable systems (structural racism),” they added. [Health Aff (Millwood) 2020;39:1624-1632; J Gerontol B Psychol Sci Soc Sci 2005;60:27-33; Lancet 2017;389:1453-1463; N Engl J Med 2016;375:2113-2115]

Current findings supported the notion that one of the key proximate mediating mechanisms for variation in outcomes among non-White persons was the presence of excess comorbidity. [J Racial Ethn Health Disparities 2017;4:623-631; Healthcare (Basel) 2018;doi:10.3390/healthcare6010002]

The present study was limited by the involvement of an insured population in a highly integrated health system, according to the researchers.