Imaging utilization wrinkle: Patients who get CT scans for headaches return to the ED less often

In a retrospective analysis of an urban emergency department that sees more than 85,000 annual visits, atraumatic headache patients who received CT scans in the ED and had negative findings were much less likely than patients who were not scanned to come back to the ED for any reason within 30 days.

It’s unclear whether the effect owed to patient reassurance, physician confidence or a combination of factors. In any case, the study’s authors note that, if future studies bear out the relationship between CT headache scans and decreased ED revisits, then determining the appropriateness of such imaging—which is regularly named a frequent “low-value” offender—“may need to be reevaluated in a context that includes effect on downstream resource use in addition to safety and quality.”

The American Journal of Roentgenology has posted the study online.

Brian Patterson, MD, MPH, of the University of Wisconsin and colleagues analyzed the cases of all adult patients who came into the ED with a chief complaint of headache and were discharged after ED evaluation during calendar year 2010.

The team excluded cases involving ED deaths, transfers and head trauma. To control for potential confounding variables, they used a propensity score–matched logistic regression model to determine whether the use of brain CT was associated with the primary outcome of ED revisitation within 30 days.

Looking at 922 ED discharges with a chief complaint of headache, Patterson and colleagues found that a total of 139 patients (15.1 percent) revisited within 30 days.

Among patients who underwent CT at their initial visit, the revisit rate was cut nearly in half versus those who did not receive CT—11.2 percent and 21.1 percent, respectively.

Further, in the study team’s adjusted analysis, which controlled for age, race, sex, insurance status, triage vital signs, laboratory values and triage pain level, the odds ratio for revisitation after CT exam was 0.49.

In their discussion, Patterson et al. note that the causes for the association they found are likely multifactorial, and they emphasize that their study does not support the conclusion that increasing CT use would directly improve revisit rates.

Rather, they write, their findings raise the consideration that future appropriate-use quality metrics reflecting ED imaging may need to incorporate data on downstream diagnostics and treatments.  

And that goes not only for atraumatic headache care.

“In an environment seeking to improve the efficiency of acute care delivery and lower healthcare costs, a relationship between these two high-cost events (imaging and ED revisits) could affect how performance measures are structured going forward across a wide variety of clinical conditions, including headache, chest pain and minor traumatic injuries as well,” they write.

“Rather than develop performance measures for emergency medicine focused on a single ED encounter,” the authors conclude, “consideration of the broader acute care episode may be needed to more accurately assess appropriate or inappropriate ED interventions and healthcare use.”