Study finds doubling of imaging studies in managed care
Use of radiology imaging tests has soared in the past decade with a significant increase in newer technologies, according to a new study that is the first to track imaging patterns in a managed care setting over a substantial time period. Study results are reported in the November/December 2008 issue of the journal Health Affairs.

A team of researchers from the University of California, San Francisco and the Group Health Center for Health Studies in Seattle conducted the study using data from 377,000 patients enrolled in the Group Health Cooperative in Washington State between 1997 and 2006. The study population underwent 5 million radiology tests during this 10-year period.

Analysis showed an increase in all types of imaging technologies, with the majority of the tests being x-ray procedures. The average total imaging cost per patient, per year doubled during the study period—from $229 to $443.

The most striking finding was the increase in the number of newer and pricier tests such as CT and MRI scans, according to the research team. In 1997, 13.5 percent of the study group had undergone a CT, MRI, or both, and in 2006 it was 21 percent. Study results showed the per-patient number of CT scans doubled over the 10 years, and the number of MRI scans tripled.

This increase in CT and MRI imaging appeared across the board, with no single patient group or disease group dominating, according to lead author Rebecca Smith-Bindman, MD, an associate professor of radiology and biomedical imaging, epidemiology and biostatistics, and obstetrics, gynecology, and reproductive sciences at University of California-San Francisco (UCSF).

The goal with newer imaging tests is to use them in the most efficient and effective way possible and as a replacement for older, less accurate tests, emphasized Smith-Bindman. “But we found the newer tests, such as CT and MRI, are being added on top of the old tests, such as x-rays, rather than replacing them—and this increases costs.

“Using these tests wisely can detect treatable diseases and save lives,” she said.  “Excess imaging may be too much of a good thing. The benefit of testing needs to be balanced against the risk.”

The study findings also highlighted concern about a correlation between the type of healthcare practice and rates of imaging, Smith-Bindman noted.

“Unlike managed-care systems such as Group Health that receive a fixed amount to care for each patient, fee-for-service practices get financial rewards for doing extra testing, including recouping investments in office-based scanning equipment,” she said. “It is likely those rates of testing are higher in fee-for-service practice, and this habit of doing more imaging may be spreading into managed care.”

The study did not address the appropriateness of imaging and whether the increase was associated with improvements in patient care. This is an area that needs further study, the research team noted.