DENVER – Considerable variation exists in emergency department use of computed tomography or ultrasound for children with abdominal pain and appendicitis, results from a large national study demonstrated.
"Despite the greater diagnostic accuracy of CT, use of CT is decreasing for these conditions, while ultrasound use has been increasing," Michael C. Monuteaux, Sc.D., said at the annual meeting of the Pediatric Academic Societies.
Increasing use of either imaging modality was associated with negative appendectomy rates, said Dr. Monuteaux, a senior biostatistician at Children’s Hospital Boston. "As the hospital-level imaging increased, the hospital-level negative appendectomy [rate] decreased."
The findings come from an analysis of the Pediatric Health Information System, a database maintained by 40 U.S. pediatric hospitals. The researchers studied 8,959,155 visits that patients under the age of 19 years made to emergency departments between 2005 and 2009 with a primary diagnosis of appendicitis, abdominal pain, or common, nontraumatic, acute disease mimickers of appendicitis.
Of these patients, 564,595 (6%) had abdominal pain and 55,238 (0.6%) had appendicitis.
The use of CT in patients with a diagnosis of appendicitis ranged from 21% to 49%, for a median of 34%, while the use of CT for other diagnoses ranged from 5% to 9%, for a median of 6%, Dr. Monuteaux reported.
Use of ultrasound in patients with a diagnosis of appendicitis ranged from 2% to 26%, for a median of 7%, while use of ultrasound for other diagnoses ranged from 2% to 8%, for a median of 6%.
Among patients diagnosed with appendicitis, CT rates decreased from a peak of 35% in 2007 to 29% in 2009, while ultrasound rates increased from 17% in 2005 to 25% in 2009.
Among patients with other diagnoses, CT rates decreased from a peak of 35% in 2007 to 29% in 2009, while ultrasound rates increased from 17% in 2005 to 25% in 2009.
The researchers observed no correlations between rates of either imaging modality and rates of perforated appendicitis. Increasing use of either CT or ultrasound was associated with decreasing negative appendectomy rates. In fact, for every 10% decrease in imaging, there was a 6.4% decrease in negative appendectomy rates.
Dr. Monuteaux acknowledged certain limitations of the study, including the fact that the cohort was drawn from an administrative database, "so it’s difficult to infer clinical management and outcome. We [also] could not adjust for any imaging that may have been done outside of the hospital prior to transfer. We also could not control or account for external factors such as [emergency department] crowding, the surrounding primary care network, or access to care that could possibly influence imaging."
He also noted that the association between type of imaging and patient-level perforation may be related to institutional clinical practice when perforation is suspected.
Dr. Monuteaux said that he had no relevant financial conflicts to disclose.
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