African Americans Are Less Likely to Receive Care by a Cardiologist During an Intensive Care Unit Admission for Heart Failure

Using the Premier healthcare database, the authors analyzed the data of over 100,000 adult patients admitted to an ICU in the U.S. with a primary diagnosis of heart failure from 2010-2014.  Hierarchical logistic regression models revealed that the likelihood of care by a cardiologist was 42% higher for white as opposed to black patients with heart failure.  Cox regression showed that care by a cardiologist was associated with a 20% higher likelihood of survival.
Question:  Is this healthcare disparity a true disparity based on race, or are other confounding and unaccounted for variables responsible?