Utilization of radiologic services in different payment systems and patient populations

PURPOSE: To report population-based utilization rates and their variability across and within populations, geographic areas, and different payment systems for diagnostic radiology and radiation oncology procedures. MATERIALS AND METHODS: Aggregated claims data were obtained from four sources for up to nine radiologic modalities. The data cover Medicare, health maintenance organizations (HMOs), and conventional insurance. For some sources, the data were separated into four age groups. All radiologic services, including those provided by nonradiologists, were included. RESULTS: Average annual ambulatory diagnostic radiology utilization rates ranged from 570 procedures per 1,000 nonelderly persons in an HMO setting to 1,970 per 1,000 for Medicare enrollees. Radiation oncology utilization rate added 11 procedures per 1,000 to the HMO population rate and 260 per 1,000 to the Medicare population rate. In the Medicare data, the diagnostic radiology utilization rate in the 25th percentile state was 78% of the rate in the 75th percentile state. In a small sample of HMOs, the 25th percentile HMO rate was 45% of the 75th percentile HMO rate. CONCLUSION: Much variability exists in utilization rates. National or regional averages are not a good guide to the utilization rates in a specific patient population and should not be taken as norms. Only actual data from a patient population are likely to provide radiologists with fairly accurate predictions of their future utilization rates.