A team of American researchers has found that markers of poor visit communication and poor ratings of care appear to be associated with clinician implicit attitudes about race as well as race and compliance stereotyping. General racial bias was associated with:

More clinician verbal dominance.
Lower patient positive affect.
Poorer ratings of interpersonal care among African-American patients.

Bias among Caucasian patients was associated with more verbal dominance and better ratings of interpersonal care.

Abstract: American Journal of Public Health, May 2012.