The geographic availability and associated utilization of dual-energy X-ray absorptiometry (DXA) testing among older persons in the United States

Abstract

Using national Medicare data from 1999-2006, we evaluated the relationship between travel distance and receipt of dual-energy X-ray absorptiometry (DXA). After adjusting for potentially confounding factors, travel distance was strongly associated with DXA testing. Rural residents were most strongly dependent on the availability of DXAs performed in physician offices.

Introduction: Medicare reimbursement for DXAs performed in non-facility settings (e.g., physician offices) decreased in 2007. With declining reimbursement, some DXA providers may cease providing this service, which would increase travel distance for some people. The impact of travel distance on access to DXA is unclear.

Methods: Using national Medicare data, we identified claims for DXA to evaluate trends in the number and locations of DXAs performed. Travel distance was the distance from beneficiaries' residence and the nearest DXA provider. Binomial regression evaluated the relationship between travel distance and receipt of DXA.

Results: In 2006, 2.9 million DXAs were performed, a 103% increase since 1999. In 2005-2006, 8.0% of persons were tested at non-facility sites versus 4.2% at facility sites. The remainder (88%) had no DXA. Persons traveling 5-9, 10-24, 25-39, and 40-54, and > or = 55 miles were less likely to receive DXA (adjusted risk ratios = 0.92, 0.79, 0.43, 0.32, and 0.26, respectively, < 5 miles referent). Rural residents were more dependent than urban residents on the availability of DXA from non-facility providers.

Conclusion: Approximately two-thirds of DXAs in 2005-2006 were performed in non-facility settings (e.g., physician offices). Rural residents would have preferentially reduced access to DXA if there were fewer non-facility sites.

Figure 1

Change in Number of Central DXAs performed at Non-Facility* and Facility Sites, 1999–2006 * Non-facility sites are those outside of a hospital (e.g. a physician office)

Figure 2

Figure 2a. Geographic Distribution of All Sites Performing Central DXAs in 2006 Figure 2b. Geographic Distribution of Facility Sites Performing Central DXAs in 2006, After Excluding Non-Facility Sites

Figure 2

Figure 2a. Geographic Distribution of All Sites Performing Central DXAs in 2006 Figure 2b. Geographic Distribution of Facility Sites Performing Central DXAs in 2006, After Excluding Non-Facility Sites