Researchers examine racial, ethnic differences in ED imaging utilization

Are there racial and ethnic disparities in the use of diagnostic imaging in the emergency department (ED)?

Researchers explored this question and discussed the implications of their findings in a recent study published in the Journal of the American College of Radiology.

“Sociodemographic disparities have been noted in the use of medical imaging in the ED in certain circumstances; however, to our knowledge, no studies of nationally representative data have explored racial and ethnic differences in ED medical imaging while accounting for patient-level factors and facility-level differences in imaging use,” wrote Justin Schrager, MD, MPH, with Emory University School of Medicine’s Department of Emergency Medicine in Atlanta, and colleagues.

The team performed a multilevel stratified regression analysis of a nationally representative database of hospital-based ED visits performed between 2005 and 2014. They examined multiple races, including white, black, Asian, American Indian, Alaska native, Native Hawaiian or other Pacific Islander and ethnicity (Hispanic or non-Hispanic) as the prime exposures for the outcomes of ED imaging use. Other patient-level and facility-level determinants were controlled for.

About 48.8% of the 225,037 adult visits included imaging. Broken down by modality, 36.1% underwent x-ray, 16.4% CT, 4.1% ultrasound and 0.8% MRI.

Results revealed “large racial differences” in imaging utilization. After multivariate adjustment, black patients had 14% lower odds of receiving imaging during an ED visit and 20% lower odds of receiving a CT scan compared with white patients. This difference was not seen in x-ray or ultrasound, however.

Additional notable results included the following:

  • White patients received imaging during 51.3% of visits, compared to 43.6% for black patients, 50.8% for Asians and 46% for other races.
  • Hispanic and Asian patients received ultrasound in the ED in 36% of visits, compared to 25% for non-Hispanic white patients.
  • Women and men had similar rates of imaging in the ED, but that varied greatly by modality. For example, men received more x-rays than women, but 3.4% fewer ultrasounds.

Possible explanations

There is likely no single factor that can explain the differences in ED utilization, the authors noted. For one, a lack of provider-level clinical decision-making information does not allow the researchers to conclude whether the difference between black and white patients is due to underutilization in that race or overutilization in other groups.

“The findings of several large observational studies of racial and ethnic disparities in ED care suggest that the underuse of key clinical resources by race and ethnicity in the ED is probably more likely,” the researchers wrote.

Schrager and colleagues dedicated a lengthy portion of their study to limitations, including the fact that their dataset does not include patient preference information. Additionally, the nationally representative dataset included hospitals that may have been sampled more than once, which could have resulted in overrepresentation.

“Therefore, due to limitations in the data source, we cannot specifically call these findings a true health care disparity, because they are suggestive of but do not prove that the differences in imaging utilization by race and ethnicity are the result of differences in health needs, clinical appropriateness, patient choice, or provider preference,” the team concluded. “However, despite this, the differences in ED imaging use by race and ethnicity as demonstrated in this multiyear, nationally representative data source warrant further investigation.”