title: Exploratory analysis of high CT scan utilization in claims data.
abstract: OBJECTIVE
  This study explores characteristics that distinguish higher and lower CT use by patients and referring physicians in a population of members of a large health insurance plan.
  
  
  METHODS
  We analyzed 310,467 CT scan claims from 2009-10 in a health plan serving approximately 1.5 million members. Patients who used CT scans and their referring physicians were classified into utilization categories. Characteristics distinguishing higher from lower utilization categories were identified.
  
  
  RESULTS
  Among patients receiving CT scans, patient characteristics that distinguished higher from lower utilization of scans were: male, older, seeing more total providers, using more prescription and total resources, classified as frail, having higher treatment group severity, and having government insurance. Among physicians ordering scans, physician characteristics that distinguished higher from lower referrals for CT scans were: male, board-certified, in group practice, and in particular specialties. Ownership interest was associated with higher claim volumes in a curvilinear manner but was not associated with claims per physician. Higher total referral counts were related to single-specialty practice type and larger group size. External reviewers (4 physicians) observed that the empirical relationships had plausible explanations based on reasonable medical decision-making.
  
  
  CONCLUSIONS
  Aggregate-level review of claims for CT scans in a health plan revealed no striking anomalies in associations of patient and referring physician characteristics with higher utilization. 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.
authors.affiliation: Division of Health Policy and Management, School of Public Health, University of Minnesota, Minneapolis, Minnesota. Electronic address: begun001@umn.edu.
authors.forename: James W
authors.initials: JW
authors.lastname: Begun
authors.affiliation: School for the Science of Health Care Delivery, College of Health Solutions, Arizona State University, Tempe, Arizona.
authors.forename: William J
authors.initials: WJ
authors.lastname: Riley
authors.affiliation: Division on Biostatistics School of Public Health, University of Minnesota, Minneapolis, Minnesota.
authors.forename: James S
authors.initials: JS
authors.lastname: Hodges
mesh_terms: D017677:Age Distribution; D017048:Health Care Costs / Q000706:statistics & numerical data*; D007349:Insurance, Health, Reimbursement / Q000191:economics* / Q000706:statistics & numerical data*; D012017:Referral and Consultation / Q000191:economics* / Q000706:statistics & numerical data*; D017678:Sex Distribution; D014057:Tomography, X-Ray Computed / Q000191:economics* / Q000706:statistics & numerical data*; D014481:United States; D014600:Utilization Review
keywords: CT scans; overutilization; quality improvement; technology