An aggregate-level review of claims for CT scans in a health plan showed no striking anomalies in associations of patient and referring physician characteristics with higher utilization, according to a study published in the January 2014 issue of the Journal of the American College of Radiology.

Use of CT scanning in the U.S. has raised concerns about appropriateness and overutilization for health care providers, payers, and consumers. “Many factors explain high or ‘uncritical’ use of CT scans in the United States, including technological advances that have expanded indications for its use, increased availability of CT scanners, patient pressure on physicians, physician concern about liability risk, and favorable financial reimbursement for imaging procedures,” wrote the study’s lead author, James W. Begun, PhD, of the University of Minnesota in Minneapolis, and colleagues.

The researchers explored characteristics that distinguish higher and lower CT use by patients and referring physicians in a population of members from a large, Midwestern health insurance plan. Begun and colleagues analyzed 310,467 CT scan claims from 2009 and 2010, with CT scan utilization investigated as a function of patient, disease, physician, and physician organization characteristics.

The health plan patients and physicians who ordered scans were separately aggregated into utilization groups in order to establish profiles of higher utilizing patients and physicians. Those who were lower utilizers were compared with those who were higher for a variety of characteristics. Once the analysis was complete, four physicians reviewed the findings for evidence of potential overutilization.

Results revealed higher patient utilization among males, with 41.1 percent of low utilizers and 49.2 percent of high utilizers being men. Older patients were more likely to be in the higher utilization categories. Patient utilization wasn’t significantly associated with the education level of a patient’s residence zip code. The median family income in the patient’s zip code declined significantly between low and moderate utilization. High and moderate utilizing patients were more likely than their lower counterparts to have government insurance.

Higher utilizing patients were more likely to see more providers; the average number of providers seen by low utilizers was 14.1, 24.1 for moderate utilizers, and 29.7 for high utilizers. As utilization increased, patients using CT scans were more likely to be classified as frail.

Referring physicians in the higher utilization categories were more likely to be in group practice and have board-certification. The higher referral categories were comprised of a higher proportion of male physicians. Specialty was associated with CT scan referral. Of these specialties, 34.7 percent of oncologists were found in the higher categories, followed by general surgeons, neurosurgeons, urologists, and internists. Physicians in groups with higher utilization rates were more likely to be in a single-specialty practice and were smaller in practice size. Smaller groups averaged at 4.3 scans per provider whereas larger groups averaged at 1.04 scans per provider.

The external review conducted by the four physicians indicated that the findings generally matched their expectations based on their professional experience. They believed that the empirical relationships had plausible explanations based on reasonable medical decision-making.

Importantly, aggregate insurance claims analysis may have been too gross to showcase patterns of overutilization, the authors wrote. “Claims research that examines particular conditions and patients with high utilization rates and physicians with high referral rates would advance the evidence base for quality improvement,” they concluded.