(Reuters) – A study of coronovirus patients in Atlanta has found that black patients are more likely to be hospitalized than white patients, highlighting racial disparities in the U.S. healthcare system, researchers from the Centers for Disease Control and Prevention (CDC) said on Wednesday.

About 79% of black patients were hospitalized for COVID-19, the disease caused by the novel coronavirus, against 13% of white patients, according to the study here across six metropolitan hospitals and outpatient clinics in Atlanta, Georgia, between March and April 2020.

The researchers found there was an association between being black and the rate of hospitalization in Atlanta, even when they controlled for underlying conditions such as diabetes.

This suggested that other factors like healthcare access or the possibility of bias might explain higher rates of hospitalization for black Americans.

Hospitalized patients tended to be older, male, black, and have underlying conditions, said the researchers. They added that black Americans were more likely to be frontline industry or essential workers, raising their risks for coronavirus infection.

Apart from age, race and underlying conditions, lack of insurance, smoking and obesity were independently associated with the likelihood of hospitalization for the 531 Atlanta patients studied, researchers said.

“The COVID-19 pandemic has highlighted persistent health disparities in the United States,” said the authors, including those from CDC’s COVID-19 Emergency Response Team and Epidemic Intelligence Service.