The use of diagnostic imaging has more than doubled since 1996, as has the mean per-capita radiation dose, raising concerns about patients' lifetime cancer risk, according to a study published this week in the Journal of the American Medical Association.
The review of six large integrated healthcare systems found imaging used at levels similar to that of Medicare patients, for whom previous research had attributed the increases in part to fee-for-service payment models that reward doctors for ordering the costly tests. The new study, out of the University of California, San Francisco, however, finds a similar pattern in HMOs, where doctors receive little or no financial incentive.
The study looked at the records of between 1 million and 2 million patients each year from 1996 to 2010, a total of 30.9 million imaging exams. That averages out to 1.18 tests per person per year, 35 percent involving advanced imaging such as CT, MRI or nuclear medicine.
Lead author Dr. Rebecca Smith-Bindman told Reuters that the factors driving the increase could be a lack of uniform imaging guidelines, fear of malpractice lawsuits and the belief that imaging is a panacea. At current rates, according to the study, 2 percent of future cancers could be attributed to imaging.
The study found that imaging use rose with patient age and that patterns varied wildly from system to system, with some types of imaging performed five to 10 times more often in one system compared with the others. Teleradiologist Richard Abramson wrote in the May issue of Radiology about his concerns about the wide variability in practice.
Contacted by Reuters, the Medical Imaging & Technology Alliance, which represents imaging equipment makers such as General Electric and Siemens, pointed to declining rates of imaging, a trend borne out in market research from vendor IMV's Medical Information Division.
Smith-Bindman, however, maintains that imaging rates still are too high, exposing patients to more radiation than necessary.
"The increase in use of advanced diagnostic imaging has almost certainly contributed to both improved patient care processes and outcomes, but there are remarkably few data to quantify the benefits of imaging," the study's authors wrote. "Given the high costs of imaging--estimated at $100 billion annually--and the potential risks of cancer and other harms, these benefits should be quantified and evidence-based guidelines for using imaging should be developed that clearly balance benefits against financial costs and health risk."