Patients - Not Doctors - Affect ED Imaging Rates

June 25, 2013

Radiology tests in emergency departments are most often requested by the patients, not the ordering physicians.

The amount of radiologic imaging ordered in the emergency department is driven largely by patients’ wishes - not the physicians’ - say the results of a study published online in the journal Radiology.

Imaging rates in emergency departments are quite variable, suggesting that physicians’ experience and training may play a role in how often these tests are ordered. To address this issue, researchers from Massachusetts General in Boston and the University of Florida in Gainesville undertook a study that analyzed ED visits to determine predictors for ordering a radiologic exam.

“A lot of literature on imaging variability can lead to a false assumption that doctors are primarily responsible,” lead author Christopher L. Sistrom, MD, MPH, PhD, said in a release. “The problem is that it is difficult to fully describe and quantify variability at the different levels it can occur.”

The researchers looked at 88,851 ED visits that occurred during 2011 at Massachusetts General Hospital. Using hierarchical logistic regression to identify multiple predictors of probability that imaging was ordered during a given visit, the researchers found that patient and visit factors were the predominant predictors that an imaging test would be performed.

“The key finding in our study is that doctors don’t make a difference in imaging utilization,” Sistrom said. He noted that doctors were responsible for only about a 1 percent variability in the probability of the patient undergoing an imaging exam.

The researchers also found that how busy an ED was played a role in the number of imaging tests ordered. In a quieter ED, the odds of low-cost imaging were 11 percent higher than the reference standard. A busier ED often ordered more higher-cost imaging.