Computed tomography utilization in the North Carolina Medicaid population with a focus on "high exposure" patients,...

We examined trends in utilization of computed tomography (CT) among Medicaid enrollees in North Carolina, the clinical setting in which those CT scans were performed, and the number of enrollees known to have undergone 10 or more scans in a given year.

North Carolina Medicaid claims were analyzed to determine the number of CT studies performed between January 1, 2007, and December 31, 2012. We assessed the number of "high exposure" patients--those who received 10 or more CT scans in a given calendar year--and divided this group into patients with a diagnosis of cancer and patients without a diagnosis of cancer. We also determined the type of site at which each CT scan was performed.

Over the 6-year period 2007-2012, the percentage of all enrollees who underwent any CT study ranged from 8.0% to 9.6% (126,082-177,425 enrollees). The number of CT scans performed annually increased from 2007 to 2009 and then plateaued. The number of high-exposure patients increased gradually, from 2,171 in 2007 to 4,017 in 2012. The majority of CT scans of high--exposure patients--150,241 of 251,052 (59.8%)--were performed in non office outpatient settings, such as emergency departments or urgent care centers.

Although the number of CT scans performed annually in the North Carolina Medicaid population stabilized in the late 2000s (as did CT use nationally), the percentage of high-exposure patients has continued to rise. Physicians and patients need to be further educated in order to promote radiation safety and to decrease unnecessary radiation exposure.