Patient--not physician--factors key to ED imaging variation

While many studies have shown that imaging utilization varies across and within emergency departments, very little of it can be laid at the feet of physician experience, training or gender, according to new research published online in the journal Radiology.

In the study, Christopher Sistrom, M.D., Ph.D., from the departments of radiology at Massachusetts General Hospital and the University of Florida, examined at 88,851 visits to the emergency department in 2011 at Massachusetts General Hospital using an analytical tool called hierarchical logistical regression. Sistrom was able to identify multiple predictors of the probability that low- or high-cost imaging would be ordered during a given visit.

The overall rate of imaging utilization at the Massachusetts General emergency department was 45.4 percent in 2011, compared to the national average of 47.2 percent; according to the study, analysis of the data showed that factors associated with physicians, like gender, experience and training, didn't correlate with imaging used.

"The key finding in our study is that doctors don't make much difference in imaging utilization," Sistrom said in an announcement. "Our data showed that doctors are responsible for about 1 percent of the variability in probability of having an imaging exam during an ED visit."

However, the researchers did find that patient and visit-level factors--such as the how busy the ED department was, prior ED visits, referral source to the ED and ED arrival mode--statistically were significant predictors of imaging use. For example, a less busy emergency department increased the odds of low-cost imaging being used, while a busier ED usually led to more high-cost imaging.

Consequently, Sistrom said, any efforts to reduce emergency department imaging by focusing on training or educating physicians probably won't work. "To reduce imaging utilization, a lot of people in quality improvement and medical management might try to identify high outliers and punish the," he said. "In settings like the one we studied, that strategy won't get you anything by angry doctors."

To learn more:
- see the study in Radiology
- read the announcement