Physician bias does not affect hypertension treatment for minority patients, study suggests

The new research, led by Irene Blair, an associate professor in CU-Boulder's Department of Psychology and Neuroscience, is published in the Journal of General Internal Medicine.

"We know that minorities have to face bias and discrimination in many different settings, and this can happen just as easily in health care," Blair said. "So it's really good news to find no evidence of bias in hypertension treatment. It helps us figure out best practices for building trust and partnership in medicine."

The study is part of a larger research project examining physician bias that involves doctors and patients at Kaiser Permanente and Denver Health.

"As a nonprofit health care organization, Kaiser Permanente is committed to improving the health of our members and the communities we serve," said John Steiner, M.D., M.P.H., study co-author and senior director of the Kaiser Permanente Institute for Health Research. "This research aligns with our mission and is absolutely critical to our body of work focused on understanding and eliminating health care disparities."

In earlier phases of the study -- published in the American Journal of Public Health and the Annals of Family Medicine -- the research team found that about two-thirds of the participating doctors had varying levels of "implicit," or unconscious, bias against African Americans or Latinos. The result mirrors the biases found generally in the Denver metro area.

The researchers then asked nearly 3,000 patients who were treated regularly for high blood pressure to rate their doctors on interpersonal treatment, communication, trust and contextual knowledge about the patient. The greater a doctor's implicit bias in favor of whites over African Americans, the lower the ratings given by the doctor's African-American patients. The researchers did not find a similar effect for Latino patients.

"The results for African-American patients are consistent with other studies that show doctors' implicit biases are not entirely hidden from patients, and more needs to be done to ensure that minority patients feel respected and welcome in health care settings," Blair said.

In the new, final phase of the study, the researchers looked at pharmacy records of nearly 5,000 patients to see if the doctors' implicit biases were reflected in patterns of prescriptions for their minority patients' high blood pressures. The researchers calculated the proportion of time that a patient's current medication was increased or a new medication was started in response to an elevated high blood pressure reading during an office visit.

The results were clear. African American and Latino patients of doctors with "high bias" received exactly the same intensification of treatment in response to high blood pressure -- upping the dose or adding a new medication -- as patients of a doctor with "low bias."

Similarly, when the research team looked at whether the patients continued to take their medications as prescribed and whether the patients' blood pressures were appropriately controlled across three years, they again found no relation between these outcomes and the doctors' implicit biases.

The researchers suggest that ethnic or racial bias may affect outcomes in other health care settings. For example, biased outcomes are more likely when doctors and patients don't have an established relationship, the medical guidelines are ambiguous or decisions must be made under more extreme time pressures.